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Various Native American groups have historically hunted beavers for food, they preferred its meat more than other red meats because of its higher calorie and fat content, and the animals remained plump in winter when they were most hunted. The bones were used to make tools. In medieval Europe, the Catholic Church considered the beaver to be part mammal and part fish, and allowed followers to eat the scaly, fishlike tail on meatless Fridays during Lent. Beaver tails were thus highly prized in Europe; they were described by French naturalist Pierre Belon as tasting like a "nicely dressed eel". Beaver pelts were used to make hats; felters would remove the guard hairs. The number of pelts needed depended on the type of hat, with Cavalier and Puritan hats requiring more fur than top hats. In the late 16th century, Europeans began to deal in North American furs due to the lack of taxes or tariffs on the continent and the decline of fur-bearers at home. Beaver pelts caused or contributed to the Beaver Wars, King William's War, and the French and Indian War; the trade made John Jacob Astor and the owners of the North West Company very wealthy. For Europeans in North America, the fur trade was a driver of the exploration and westward exploration on the continent and contact with native peoples, who traded with them. The fur trade peaked between 1860 and 1870, when over 150,000 beaver pelts were purchased annually by the Hudson's Bay Company and fur companies in the United States. The contemporary global fur trade is not as profitable due to conservation, anti-fur and animal rights campaigns.
In culture. The beaver has been used to represent productivity, trade, tradition, masculinity, and respectability. References to the beaver's skills are reflected in everyday language. The English verb "to beaver" means working with great effort and being "as busy as a beaver"; a "beaver intellect" refers to a way of thinking that is slow and honest. Though it typically has a wholesome image, the beaver's name has been used as a sexual term for the human vulva. Native American myths emphasize the beaver's skill and industriousness. In the mythology of the Haida, beavers are descended from the Beaver-Woman, who built a dam on a stream next to their cabin while her husband was out hunting and gave birth to the first beavers. In a Cree story, the Great Beaver and its dam caused a world flood. Other tales involve beavers using their tree chewing skills against an enemy. Beavers have been featured as companions in some stories, including a Lakota tale where a young woman flees from her evil husband with the aid of her pet beaver.
Europeans have traditionally thought of beavers as fantastical animals due to their amphibious nature. They depicted them with exaggerated tusk-like teeth, dog- or pig-like bodies, fish tails, and visible testicles. French cartographer Nicolas de Fer illustrated beavers building a dam at Niagara Falls, fantastically depicting them like human builders. Beavers have also appeared in literature such as Dante Alighieri's "Divine Comedy" and the writings of Athanasius Kircher, who wrote that on Noah's Ark the beavers were housed near a water-filled tub that was also used by mermaids and otters. The beaver has long been associated with Canada, appearing on the first pictorial postage stamp issued in the Canadian colonies in 1851 as the so-called "Three-Penny Beaver". It was declared the national animal in 1975. The five-cent coin, the coat of arms of the Hudson's Bay Company, and the logos for Parks Canada and Roots Canada use its image. Frank and Gordon are two fictional beavers that appeared in Bell Canada's advertisements between 2005 and 2008. However, the beaver's status as a rodent has made it controversial, and it was not chosen to be on the Arms of Canada in 1921. The beaver has commonly been used to represent Canada in political cartoons, typically to signify it as a friendly but relatively weak nation. In the United States, the beaver is the state animal of New York and Oregon. It is also featured on the coat of arms of the London School of Economics.
Bear Bears are carnivoran mammals of the family Ursidae (). They are classified as caniforms, or doglike carnivorans. Although only eight species of bears are extant, they are widespread, appearing in a wide variety of habitats throughout most of the Northern Hemisphere and partially in the Southern Hemisphere. Bears are found on the continents of North America, South America, and Eurasia. Common characteristics of modern bears include large bodies with stocky legs, long snouts, small rounded ears, shaggy hair, plantigrade paws with five nonretractile claws, and short tails. While the polar bear is mostly carnivorous, and the giant panda is mostly herbivorous, the remaining six species are omnivorous with varying diets. With the exception of courting individuals and mothers with their young, bears are typically solitary animals. They may be diurnal or nocturnal and have an excellent sense of smell. Despite their heavy build and awkward gait, they are adept runners, climbers, and swimmers. Bears use shelters, such as caves and logs, as their dens; most species occupy their dens during the winter for a long period of hibernation, up to 100 days.
Bears have been hunted since prehistoric times for their meat and fur; they have also been used for bear-baiting and other forms of entertainment, such as being made to dance. With their powerful physical presence, they play a prominent role in the arts, mythology, and other cultural aspects of various human societies. In modern times, bears have come under pressure through encroachment on their habitats and illegal trade in bear parts, including the Asian bile bear market. The IUCN lists six bear species as vulnerable or endangered, and even least concern species, such as the brown bear, are at risk of extirpation in certain countries. The poaching and international trade of these most threatened populations are prohibited, but still ongoing. Etymology. The English word "bear" comes from Old English ' and belongs to a family of names for the bear in Germanic languages, such as Swedish ', also used as a first name. This form is conventionally said to be related to a Proto-Indo-European word for "brown", so that "bear" would mean "the brown one". However, Ringe notes that while this etymology is semantically plausible, a word meaning "brown" of this form cannot be found in Proto-Indo-European. He suggests instead that "bear" is from the Proto-Indo-European word "*ǵʰwḗr- ~ *ǵʰwér" "wild animal". This terminology for the animal originated as a taboo avoidance term: proto-Germanic tribes replaced their original word for bear—"arkto"—with this euphemistic expression out of fear that speaking the animal's true name might cause it to appear. According to author Ralph Keyes, this is the oldest known euphemism.
Bear taxon names such as Arctoidea and "Helarctos" come from the ancient Greek ἄρκτος ("arktos"), meaning bear, as do the names "arctic" and "antarctic", via the name of the constellation Ursa Major, the "Great Bear", prominent in the northern sky. Bear taxon names such as Ursidae and "Ursus" come from Latin "Ursus/Ursa", he-bear/she-bear. The female first name "Ursula", originally derived from a Christian saint's name, means "little she-bear" (diminutive of Latin "ursa"). In Switzerland, the male first name "Urs" is especially popular, while the name of the canton and city of Bern is by legend derived from "Bär", German for bear. The Germanic name Bernard (including Bernhardt and similar forms) means "bear-brave", "bear-hardy", or "bold bear". The Old English name Beowulf is a kenning, "bee-wolf", for bear, in turn meaning a brave warrior. Taxonomy. The family Ursidae is one of nine families in the suborder Caniformia, or "doglike" carnivorans, within the order Carnivora. Bears' closest living relatives are the pinnipeds, canids, and musteloids. (Some scholars formerly argued that bears are directly derived from canids and should not be classified as a separate family.) Modern bears comprise eight species in three subfamilies: Ailuropodinae (monotypic with the giant panda), Tremarctinae (monotypic with the spectacled bear), and Ursinae (containing six species divided into one to three genera, depending on the authority). Nuclear chromosome analysis show that the karyotype of the six ursine bears is nearly identical, each having 74 chromosomes ("see" Ursid hybrid), whereas the giant panda has 42 chromosomes and the spectacled bear 52. These smaller numbers can be explained by the fusing of some chromosomes, and the banding patterns on these match those of the ursine species, but differ from those of procyonids, which supports the inclusion of these two species in Ursidae rather than in Procyonidae, where they had been placed by some earlier authorities.
Evolution. The earliest members of Ursidae belong to the extinct subfamily Amphicynodontinae, including "Parictis" (late Eocene to early middle Miocene, 38–18 Mya) and the slightly younger "Allocyon" (early Oligocene, 34–30 Mya), both from North America. These animals looked very different from today's bears, being small and raccoon-like in overall appearance, with diets perhaps more similar to that of a badger. "Parictis" does not appear in Eurasia and Africa until the Miocene. It is unclear whether late-Eocene ursids were also present in Eurasia, although faunal exchange across the Bering land bridge may have been possible during a major sea level low stand as early as the late Eocene (about 37 Mya) and continuing into the early Oligocene. European genera morphologically very similar to "Allocyon", and to the much younger American "Kolponomos" (about 18 Mya), are known from the Oligocene, including "Amphicticeps" and "Amphicynodon". There has been various morphological evidence linking amphicynodontines with pinnipeds, as both groups were semi-aquatic, otter-like mammals. In addition to the support of the pinniped–amphicynodontine clade, other morphological and some molecular evidence supports bears being the closest living relatives to pinnipeds.
The raccoon-sized, dog-like "Cephalogale" is the oldest-known member of the subfamily Hemicyoninae, which first appeared during the middle Oligocene in Eurasia about 30 Mya. The subfamily includes the younger genera "Phoberocyon" (20–15 Mya), and "Plithocyon" (15–7 Mya). A "Cephalogale"-like species gave rise to the genus "Ursavus" during the early Oligocene (30–28 Mya); this genus proliferated into many species in Asia and is ancestral to all living bears. Species of "Ursavus" subsequently entered North America, together with "Amphicynodon" and "Cephalogale", during the early Miocene (21–18 Mya). Members of the living lineages of bears diverged from "Ursavus" between 15 and 20 Mya, likely via the species "Ursavus elmensis". Based on genetic and morphological data, the Ailuropodinae (pandas) were the first to diverge from other living bears about 19 Mya, although no fossils of this group have been found before about 11 Mya. The New World short-faced bears (Tremarctinae) differentiated from Ursinae following a dispersal event into North America during the mid-Miocene (about 13 Mya). They invaded South America (≈2.5 or 1.2 Ma) following formation of the Isthmus of Panama. Their earliest fossil representative is "Plionarctos" in North America (c. 10–2 Ma). This genus is probably the direct ancestor to the North American short-faced bears (genus "Arctodus"), the South American short-faced bears ("Arctotherium"), and the spectacled bears, "Tremarctos", represented by both an extinct North American species ("T. floridanus"), and the lone surviving representative of the Tremarctinae, the South American spectacled bear ("T. ornatus").
The subfamily Ursinae experienced a dramatic proliferation of taxa about 5.3–4.5 Mya, coincident with major environmental changes; the first members of the genus "Ursus" appeared around this time. The sloth bear is a modern survivor of one of the earliest lineages to diverge during this radiation event (5.3 Mya); it took on its peculiar morphology, related to its diet of termites and ants, no later than by the early Pleistocene. By 3–4 Mya, the species "Ursus minimus" appears in the fossil record of Europe; apart from its size, it was nearly identical to today's Asian black bear. It is likely ancestral to all bears within Ursinae, perhaps aside from the sloth bear. Two lineages evolved from "U. minimus": the black bears (including the sun bear, the Asian black bear, and the American black bear); and the brown bears (which includes the polar bear). Modern brown bears evolved from "U. minimus" via "Ursus etruscus", which itself is ancestral to the extinct Pleistocene cave bear. Species of Ursinae have migrated repeatedly into North America from Eurasia as early as 4 Mya during the early Pliocene. The polar bear is the most recently evolved species and descended from a population of brown bears that became isolated in northern latitudes by glaciation 400,000 years ago.
Phylogeny. The relationship of the bear family with other carnivorans is shown in the following phylogenetic tree, which is based on the molecular phylogenetic analysis of six genes in Flynn (2005) with the musteloids updated following the multigene analysis of Law et al. (2018). Note that although they are called "bears" in some languages, red pandas and raccoons and their close relatives are not bears, but rather musteloids. There are two phylogenetic hypotheses on the relationships among extant and fossil bear species. One is all species of bears are classified in seven subfamilies as adopted here and related articles: Amphicynodontinae, Hemicyoninae, Ursavinae, Agriotheriinae, Ailuropodinae, Tremarctinae, and Ursinae. Below is a cladogram of the subfamilies of bears after McLellan and Reiner (1992) and Qiu "et al.". (2014): The second alternative phylogenetic hypothesis was implemented by McKenna et al. (1997) to classify all the bear species into the superfamily Ursoidea, with Hemicyoninae and Agriotheriinae being classified in the family "Hemicyonidae". Amphicynodontinae under this classification were classified as stem-pinnipeds in the superfamily Phocoidea. In the McKenna and Bell classification, both bears and pinnipeds are in a parvorder of carnivoran mammals known as Ursida, along with the extinct bear dogs of the family Amphicyonidae. Below is the cladogram based on McKenna and Bell (1997) classification:
Physical characteristics. Size. The bear family includes the most massive extant terrestrial members of the order Carnivora. The polar bear is considered to be the largest extant species, with adult males weighing and measuring in total length. The smallest species is the sun bear, which ranges in weight and in length. Prehistoric North and South American short-faced bears were the largest species known to have lived. The latter estimated to have weighed and stood tall. Body weight varies throughout the year in bears of temperate and arctic climates, as they build up fat reserves in the summer and autumn and lose weight during the winter. Morphology. Bears are generally bulky and robust animals with short tails. They are sexually dimorphic with regard to size, with males typically being larger. Larger species tend to show increased levels of sexual dimorphism in comparison to smaller species. Relying as they do on strength rather than speed, bears have relatively short limbs with thick bones to support their bulk. The shoulder blades and the pelvis are correspondingly massive. The limbs are much straighter than those of the big cats as there is no need for them to flex in the same way due to the differences in their gait. The strong forelimbs are used to catch prey, excavate dens, dig out burrowing animals, turn over rocks and logs to locate prey, and club large creatures.
Unlike most other land carnivorans, bears are plantigrade. They distribute their weight toward the hind feet, which makes them look lumbering when they walk. They are capable of bursts of speed but soon tire, and as a result mostly rely on ambush rather than the chase. Bears can stand on their hind feet and sit up straight with remarkable balance. Their front paws are flexible enough to grasp fruit and leaves. Bears' non-retractable claws are used for digging, climbing, tearing, and catching prey. The claws on the front feet are larger than those on the back and may be a hindrance when climbing trees; black bears are the most arboreal of the bears, and have the shortest claws. Pandas are unique in having a bony extension on the wrist of the front feet which acts as a thumb, and is used for gripping bamboo shoots as the animals feed. Most mammals have agouti hair, with each individual hair shaft having bands of color corresponding to two different types of melanin pigment. Bears however have a single type of melanin and the hairs have a single color throughout their length, apart from the tip which is sometimes a different shade. The coat consists of long guard hairs, which form a protective shaggy covering, and short dense hairs which form an insulating layer trapping air close to the skin. The shaggy coat helps maintain body heat during winter hibernation and is shed in the spring leaving a shorter summer coat. Polar bears have hollow, translucent guard hairs which gain heat from the sun and conduct it to the dark-colored skin below. They have a thick layer of blubber for extra insulation, and the soles of their feet have a dense pad of fur. While bears tend to be uniform in color, some species may have markings on the chest or face and the giant panda has a bold black-and-white pelage.
Bears have small rounded ears so as to minimize heat loss, but neither their hearing or sight are particularly acute. Unlike many other carnivorans they have color vision, perhaps to help them distinguish ripe nuts and fruits. They are unique among carnivorans in not having touch-sensitive whiskers on the muzzle; however, they have an excellent sense of smell, better than that of the dog, or possibly any other mammal. They use smell for signalling to each other (either to warn off rivals or detect mates) and for finding food. Smell is the principal sense used by bears to locate most of their food, and they have excellent memories which helps them to relocate places where they have found food before. The skulls of bears are massive, providing anchorage for the powerful masseter and temporal jaw muscles. The canine teeth are large but mostly used for display, and the molar teeth flat and crushing. Unlike most other members of the Carnivora, bears have relatively undeveloped carnassial teeth, and their teeth are adapted for a diet that includes a significant amount of vegetable matter. Considerable variation occurs in dental formula even within a given species. This may indicate bears are still in the process of evolving from a mainly meat-eating diet to a predominantly herbivorous one. Polar bears appear to have secondarily re-evolved carnassial-like cheek teeth, as their diets have switched back towards carnivory. Sloth bears lack lower central incisors and use their protrusible lips for sucking up the termites on which they feed. The general dental formula for living bears is: . The structure of the larynx of bears appears to be the most basal of the caniforms. They possess air pouches connected to the pharynx which may amplify their vocalizations.
Bears have a fairly simple digestive system typical for carnivorans, with a single stomach, short undifferentiated intestines and no cecum. Even the herbivorous giant panda still has the digestive system of a carnivore, as well as carnivore-specific genes. Its ability to digest cellulose is ascribed to the microbes in its gut. Bears must spend much of their time feeding in order to gain enough nutrition from foliage. The panda, in particular, spends 12–15 hours a day feeding. Distribution and habitat. Extant bears are found in sixty countries primarily in the Northern Hemisphere and are concentrated in Asia, North America, and Europe. An exception is the spectacled bear; native to South America, it inhabits the Andean region. The sun bear's range extends below the equator in Southeast Asia. The Atlas bear, a subspecies of the brown bear was distributed in North Africa from Morocco to Libya, but it became extinct around the 1870s. The most widespread species is the brown bear, which occurs from Western Europe eastwards through Asia to the western areas of North America. The American black bear is restricted to North America, and the polar bear is restricted to the Arctic Ocean. All the remaining species of bear are Asian. They occur in a range of habitats which include tropical lowland rainforest, both coniferous and broadleaf forests, prairies, steppes, montane grassland, alpine scree slopes, Arctic tundra and in the case of the polar bear, ice floes. Bears may dig their dens in hillsides or use caves, hollow logs and dense vegetation for shelter.
Behavior and ecology. Brown and American black bears are generally diurnal, meaning that they are active for the most part during the day, though they may forage substantially by night. Other species may be nocturnal, active at night, though female sloth bears with cubs may feed more at daytime to avoid competition from conspecifics and nocturnal predators. Bears are overwhelmingly solitary and are considered to be the most asocial of all the Carnivora. The only times bears are encountered in groups are mothers with young or occasional seasonal bounties of rich food (such as salmon runs). Fights between males can occur and older individuals may have extensive scarring, which suggests that maintaining dominance can be intense. With their acute sense of smell, bears can locate carcasses from several kilometres away. They use olfaction to locate other foods, encounter mates, avoid rivals and recognize their cubs. Feeding. Most bears are opportunistic omnivores and consume more plant than animal matter, and appear to have evolved from an ancestor which was a low-protein macronutrient omnivore. They eat anything from leaves, roots, and berries to insects, carrion, fresh meat, and fish, and have digestive systems and teeth adapted to such a diet. At the extremes are the almost entirely herbivorous giant panda and the mostly carnivorous polar bear. However, all bears feed on any food source that becomes seasonally available. For example, Asiatic black bears in Taiwan consume large numbers of acorns when these are most common, and switch to ungulates at other times of the year.
When foraging for plants, bears choose to eat them at the stage when they are at their most nutritious and digestible, typically avoiding older grasses, sedges and leaves. Hence, in more northern temperate areas, browsing and grazing is more common early in spring and later becomes more restricted. Knowing when plants are ripe for eating is a learned behavior. Berries may be foraged in bushes or at the tops of trees, and bears try to maximize the number of berries consumed versus foliage. In autumn, some bear species forage large amounts of naturally fermented fruits, which affects their behavior. Smaller bears climb trees to obtain mast (edible reproductive parts, such as acorns). Such masts can be very important to the diets of these species, and mast failures may result in long-range movements by bears looking for alternative food sources. Brown bears, with their powerful digging abilities, commonly eat roots. The panda's diet is over 99% bamboo, of 30 different species. Its strong jaws are adapted for crushing the tough stems of these plants, though they prefer to eat the more nutritious leaves. Bromeliads can make up to 50% of the diet of the spectacled bear, which also has strong jaws to bite them open.
The sloth bear is not as specialized as polar bears and the panda, has lost several front teeth usually seen in bears, and developed a long, suctioning tongue to feed on the ants, termites, and other burrowing insects. At certain times of the year, these insects can make up 90% of their diets. Some individuals become addicted to sweets in garbage inside towns where tourism-related waste is generated throughout the year. Some species may raid the nests of wasps and bees for the honey and immature insects, in spite of stinging from the adults. Sun bears use their long tongues to lick up both insects and honey. Fish are an important source of food for some species, and brown bears in particular gather in large numbers at salmon runs. Typically, a bear plunges into the water and seizes a fish with its jaws or front paws. The preferred parts to eat are the brain and eggs. Small burrowing mammals like rodents may be dug out and eaten. The brown bear and both species of black bears sometimes take large ungulates, such as deer and bovids, mostly the young and weak. These animals may be taken by a short rush and ambush, though hiding young may be sniffed out and pounced on. The polar bear mainly preys on seals, stalking them from the ice or breaking into their dens. They primarily eat the highly digestible blubber. Large mammalian prey is typically killed with raw strength, including bites and paw swipes, and bears do not display the specialized killing methods of felids and canids. Predatory behavior in bears is typically taught to the young by the mother.
Bears are prolific scavengers and kleptoparasites, stealing food caches from rodents, and carcasses from other predators. For hibernating species, weight gain is important as it provides nourishment during winter dormancy. A brown bear can eat of food and gain of fat a day prior to entering its den. Communication. Bears produce a number of vocal and non-vocal sounds. Tongue-clicking, grunting or chuffing many be made in cordial situations, such as between mothers and cubs or courting couples, while moaning, huffing, snorting or blowing air is made when an individual is stressed. Barking is produced during times of alarm, excitement or to give away the animal's position. Warning sounds include jaw-clicking and lip-popping, while teeth-chatters, bellows, growls, roars and pulsing sounds are made in aggressive encounters. Cubs may squeal, bawl, bleat or scream when in distress and make motor-like humming when comfortable or nursing. Bears sometimes communicate with visual displays such as standing upright, which exaggerates the individual's size. The chest markings of some species may add to this intimidating display. Staring is an aggressive act and the facial markings of spectacled bears and giant pandas may help draw attention to the eyes during agonistic encounters. Individuals may approach each other by stiff-legged walking with the head lowered. Dominance between bears is asserted by making a frontal orientation, showing the canine teeth, muzzle twisting and neck stretching. A subordinate may respond with a lateral orientation, by turning away and dropping the head and by sitting or lying down.
Bears also communicate with their scent by urinating on or rubbing against trees and other objects. This is usually accompanied by clawing and biting the object. Bark may be spread around to draw attention to the marking post. Pandas establish territories by marking objects with urine and a waxy substance from their anal glands. Polar bears leave behind their scent in their tracks which allow individuals to keep track of one another in the vast Arctic wilderness. Reproduction and development. The mating system of bears has variously been described as a form of polygyny, promiscuity and serial monogamy. During the breeding season, males take notice of females in their vicinity and females become more tolerant of males. A male bear may visit a female continuously over a period of several days or weeks, depending on the species, to test her reproductive state. During this time period, males try to prevent rivals from interacting with their mate. Courtship may be brief, although in some Asian species, courting pairs may engage in wrestling, hugging, mock fighting and vocalizing. Ovulation is induced by mating, which can last up to 30 minutes depending on the species.
Gestation typically lasts six to nine months, including delayed implantation, and litter size numbers up to four cubs. Giant pandas may give birth to twins but they can only suckle one young and the other is left to die. In northern living species, birth takes place during winter dormancy. Cubs are born blind and helpless with at most a thin layer of hair, relying on their mother for warmth. The milk of the female bear is rich in fat and antibodies and cubs may suckle for up to a year after they are born. By two to three months, cubs can follow their mother outside the den. They usually follow her on foot, but sloth bear cubs may ride on their mother's back. Male bears play no role in raising young. Infanticide, where an adult male kills the cubs of another, has been recorded in polar bears, brown bears and American black bears but not in other species. Males kill young to bring the female into estrus. Cubs may flee and the mother defends them even at the cost of her life. In some species, offspring may become independent around the next spring, though some may stay until the female successfully mates again. Bears reach sexual maturity shortly after they disperse; at around three to six years depending on the species. Male Alaskan brown bears and polar bears may continue to grow until they are 11 years old. Lifespan may also vary between species. The brown bear can live an average of 25 years.
Hibernation. Bears of northern regions, including the American black bear and the grizzly bear, hibernate in the winter. During hibernation, the bear's metabolism slows down, its body temperature decreases slightly, and its heart rate slows from a normal value of 55 to just 9 beats per minute. In order for their heart rate to slow down to this level during hibernation, a protein found in striated muscle, like the heart, called myosin must enter a super-relaxed state. In the super-relaxed state, the consumption of ATP is kept very low, allowing the bear to make it through the winter without losing all of its energy due to the basic functions such as pumping blood through the body. Bears normally do not wake during their hibernation, and can go the entire period without eating, drinking, urinating, or defecating. A fecal plug is formed in the colon, and is expelled when the bear wakes in the spring. If they have stored enough body fat, their muscles remain in good condition, and their protein maintenance requirements are met from recycling waste urea. While larger bears have a larger supply of body fat to keep them alive through hibernation, researchers found that smaller bears were able to hibernate longer than their larger counterparts due to them being able to sustain a lower body temperature, which translates to less energy being spent on keeping their bodies warm.Female bears give birth during the hibernation period, and are roused when doing so.
Mortality. Bears do not have many predators. The most important are humans, and as they started cultivating crops, they increasingly came in conflict with the bears that raided them. Since the invention of firearms, people have been able to kill bears with greater ease. Felids like the tiger may also prey on bears, particularly cubs, which may also be threatened by canids. Bears are parasitized by eighty species of parasites, including single-celled protozoans and gastro-intestinal worms, and nematodes and flukes in their heart, liver, lungs and bloodstream. Externally, they have ticks, fleas and lice. A study of American black bears found seventeen species of endoparasite including the protozoan "Sarcocystis", the parasitic worm "Diphyllobothrium mansonoides", and the nematodes "Dirofilaria immitis", "Capillaria aerophila", "Physaloptera" sp., "Strongyloides" sp. and others. Of these, "D. mansonoides" and adult "C. aerophila" were causing pathological symptoms. By contrast, polar bears have few parasites; many parasitic species need a secondary, usually terrestrial, host, and the polar bear's life style is such that few alternative hosts exist in their environment. The protozoan "Toxoplasma gondii" has been found in polar bears, and the nematode "Trichinella nativa" can cause a serious infection and decline in older polar bears. Bears in North America are sometimes infected by a "Morbillivirus" similar to the canine distemper virus. They are susceptible to infectious canine hepatitis (CAV-1), with free-living black bears dying rapidly of encephalitis and hepatitis.
Relationship with humans. Conservation. In modern times, bears have come under pressure through encroachment on their habitats and illegal trade in bear parts, including the Asian bile bear market, though hunting is now banned, largely replaced by farming. The IUCN lists six bear species as vulnerable; even the two least concern species, the brown bear and the American black bear, are at risk of extirpation in certain areas. In general, these two species inhabit remote areas with little interaction with humans, and the main non-natural causes of mortality are hunting, trapping, road-kill and depredation. Laws have been passed in many areas of the world to protect bears from habitat destruction. Public perception of bears is often positive, as people identify with bears due to their omnivorous diets, their ability to stand on two legs, and their symbolic importance. Support for bear protection is widespread, at least in more affluent societies. The giant panda has become a worldwide symbol of conservation. The Sichuan Giant Panda Sanctuaries, which are home to around 30% of the wild panda population, gained a UNESCO World Heritage Site designation in 2006. Where bears raid crops or attack livestock, they may come into conflict with humans. In poorer rural regions, attitudes may be more shaped by the dangers posed by bears, and the economic costs they cause to farmers and ranchers.
Attacks. Several bear species are dangerous to humans, especially in areas where they have become used to people; elsewhere, they generally avoid humans. Injuries caused by bears are rare, but are widely reported. Bears may attack humans in response to being startled, in defense of young or food, or even for predatory reasons. Entertainment, hunting, food and folk medicine. Bears in captivity have for centuries been used for entertainment. They have been trained to dance, and were kept for baiting in Europe from at least the 16th century. There were five bear-baiting gardens in Southwark, London, at that time; archaeological remains of three of these have survived. Across Europe, nomadic Romani bear handlers called Ursari lived by busking with their bears from the 12th century. Bears have been hunted for sport, food, and folk medicine. Their meat is dark and stringy, like a tough cut of beef. In Cantonese cuisine, bear paws are considered a delicacy. Bear meat should be cooked thoroughly, as it can be infected with the parasite "Trichinella spiralis".
The peoples of eastern Asia use bears' body parts and secretions (notably their gallbladders and bile) as part of traditional Chinese medicine. More than 12,000 bears are thought to be kept on farms in China, Vietnam, and South Korea for the production of bile. Trade in bear products is prohibited under CITES, but bear bile has been detected in shampoos, wine and herbal medicines sold in Canada, the United States and Australia. Cultural depictions. Bears have been popular subjects in art, literature, folklore and mythology. The image of the mother bear was prevalent throughout societies in North America and Eurasia, based on the female's devotion and protection of her cubs. In many Native American cultures, the bear is a symbol of rebirth because of its hibernation and re-emergence. A widespread belief among cultures of North America and northern Asia associated bears with shaman; this may be based on the solitary nature of both. Bears have thus been thought to predict the future and shaman were believed to have been capable of transforming into bears.
There is evidence of prehistoric bear worship, though this is disputed by archaeologists. It is possible that bear worship existed in early Chinese and Ainu cultures. The prehistoric Finns, Siberian peoples and more recently Koreans considered the bear as the spirit of their forefathers. Artio ("Dea Artio" in the Gallo-Roman religion) was a Celtic bear goddess. Evidence of her worship has notably been found at Bern, itself named for the bear. Her name is derived from the Celtic word for "bear", "artos". In ancient Greece, the archaic cult of Artemis in bear form survived into Classical times at Brauron, where young Athenian girls passed an initiation rite as "arktoi" "she bears". The constellations of Ursa Major and Ursa Minor, the great and little bears, are named for their supposed resemblance to bears, from the time of Ptolemy. The nearby star Arcturus means "guardian of the bear", as if it were watching the two constellations. Ursa Major has been associated with a bear for as much as 13,000 years since Paleolithic times, in the widespread Cosmic Hunt myths. These are found on both sides of the Bering land bridge, which was lost to the sea some 11,000 years ago.
Bears are popular in children's stories, including Winnie the Pooh, Paddington Bear, Gentle Ben and "The Brown Bear of Norway". An early version of "Goldilocks and the Three Bears", was published as "The Three Bears" in 1837 by Robert Southey, many times retold, and illustrated in 1918 by Arthur Rackham. The Hanna-Barbera character Yogi Bear has appeared in numerous comic books, animated television shows and films. The Care Bears began as greeting cards in 1982, and were featured as toys, on clothing and in film. Around the world, many children—and some adults—have teddy bears, stuffed toys in the form of bears, named after the American statesman Theodore Roosevelt when in 1902 he had refused to shoot an American black bear tied to a tree. Bears, like other animals, may symbolize nations. The Russian Bear has been a common national personification for Russia from the 16th century onward. Smokey Bear has become a part of American culture since his introduction in 1944, with his message "Only you can prevent forest fires".
Organizations. The International Association for Bear Research & Management, also known as the International Bear Association, and the Bear Specialist Group of the Species Survival Commission, a part of the International Union for Conservation of Nature focus on the natural history, management, and conservation of bears. Bear Trust International works for wild bears and other wildlife through four core program initiatives, namely Conservation Education, Wild Bear Research, Wild Bear Management, and Habitat Conservation. Specialty organizations for each of the eight species of bears worldwide include:
Bald eagle The bald eagle (Haliaeetus leucocephalus) is a bird of prey found in North America. A sea eagle, it has two known subspecies and forms a species pair with the white-tailed eagle ("Haliaeetus albicilla"), which occupies the same niche as the bald eagle in the Palearctic. Its range includes most of Canada and Alaska, all of the contiguous United States, and northern Mexico. It is found near large bodies of open water with an abundant food supply and old-growth trees for nesting. The bald eagle is an opportunistic feeder which subsists mainly on fish, which it swoops down upon and snatches from the water with its talons. It builds the largest nest of any North American bird and the largest tree nests ever recorded for any animal species, up to deep, wide, and in weight. Sexual maturity is attained at the age of four to five years. Bald eagles are not bald; the name derives from an older meaning of the word, "white-headed". The adult is mainly brown with a white head and tail. The sexes are identical in plumage, but females are about 25 percent larger than males. The yellow beak is large and hooked. The plumage of the immature is brown.
The bald eagle is the national symbol of the United States and appears on its seal. In the late 20th century it was on the brink of extirpation in the contiguous United States, but measures such as banning the practice of hunting bald eagles and banning the use of the harmful pesticide DDT slowed the decline of their population. Populations have since recovered, and the species' status was upgraded from "endangered" to "threatened" in 1995 and removed from the list altogether in 2007. In 2024, the bald eagle was officially made the national bird of the United States. Taxonomy. The bald eagle is placed in the genus "Haliaeetus" (sea eagles), and gets both its common and specific scientific names from the distinctive appearance of the adult's head. "Bald" in the English name is from an older usage meaning "having white on the face or head" rather than "hairless", referring to the white head feathers contrasting with the darker body. The genus name is Neo-Latin: "Haliaeetus" (from the ), and the specific name, "leucocephalus", is Latinized () and ().
The bald eagle was one of the many species originally described by Carl Linnaeus in his 18th-century work "Systema Naturae", under the name "Falco leucocephalus". The bald eagle forms a species pair with the white-tailed eagle of Eurasia. This species pair consists of a white-headed and a tan-headed species of roughly equal size; the white-tailed eagle also has overall somewhat paler brown body plumage. The two species fill the same ecological niche in their respective ranges. The pair diverged from other sea eagles at the beginning of the Early Miocene (c. 10 Ma BP) at the latest, but possibly as early as the Early/Middle Oligocene, 28 Ma BP, if the most ancient fossil record is correctly assigned to this genus. Subspecies. There are two recognized subspecies of bald eagle: Description. The plumage of an adult bald eagle is evenly dark brown with a white head and tail. The tail is moderately long and slightly wedge-shaped. Males and females are identical in plumage coloration, but sexual dimorphism is evident in the species, in that females are 25% larger than males. The beak, feet and irises are bright yellow. The legs are feather-free, and the toes are short and powerful with large talons. The highly developed talon of the hind toe is used to pierce the vital areas of prey while it is held immobile by the front toes. The beak is large and hooked, with a yellow cere. The adult bald eagle is unmistakable in its native range. The closely related African fish eagle ("Haliaeetus vocifer") (from far outside the bald eagle's range) also has a brown body (albeit of somewhat more rufous hue), white head and tail, but differs from the bald eagle in having a white chest and black tip to the bill.
The plumage of the immature is a dark brown overlaid with messy white streaking until the fifth (rarely fourth, very rarely third) year, when it reaches sexual maturity. Immature bald eagles are distinguishable from the golden eagle ("Aquila chrysaetos"), the only other very large, non-vulturine raptorial bird in North America, in that the former has a larger, more protruding head with a larger beak, straighter edged wings which are held flat (not slightly raised) and with a stiffer wing beat and feathers which do not completely cover the legs. When seen well, the golden eagle is distinctive in plumage with a more solid warm brown color than an immature bald eagle, with a reddish-golden patch to its nape and (in immature birds) a highly contrasting set of white squares on the wing. The bald eagle has sometimes been considered the largest true raptor (accipitrid) in North America. The only larger species of raptor-like bird is the California condor ("Gymnogyps californianus"), a New World vulture which today is not generally considered a taxonomic ally of true accipitrids. However, the golden eagle, averaging and in wing chord length in its American race ("Aquila chrysaetos canadensis"), is merely lighter in mean body mass and exceeds the bald eagle in mean wing chord length by around . Additionally, the bald eagle's close cousins, the relatively longer-winged but shorter-tailed white-tailed eagle and the overall larger Steller's sea eagle ("Haliaeetus pelagicus"), may, rarely, wander to coastal Alaska from Asia.
The bald eagle has a body length of . Typical wingspan is between and mass is normally between . Females are about 25% larger than males, averaging as much as , and against the males' average weight of . The size of the bird varies by location and generally corresponds with Bergmann's rule: the species increases in size further away from the equator and the tropics. For example, eagles from South Carolina average in mass and in wingspan, smaller than their northern counterparts. One field guide in Florida listed similarly small sizes for bald eagles there, at about . Of intermediate size, 117 migrant bald eagles in Glacier National Park were found to average but this was mostly (possibly post-dispersal) juvenile eagles, with 6 adults here averaging . Wintering eagles in Arizona (winter weights are usually the highest of the year since, like many raptors, they spend the highest percentage of time foraging during winter) were found to average . The largest eagles are from Alaska, where large females may weigh more than and span across the wings. A survey of adult weights in Alaska showed that females there weighed on average , respectively, and males weighed against immatures which averaged and in the two sexes. An Alaskan adult female eagle that was considered outsized weighed some . R.S. Palmer listed a record from 1876 in Wyoming County, New York of an enormous adult bald eagle that was shot and reportedly scaled . Among standard linear measurements, the wing chord is , the tail is long, and the tarsus is . The culmen reportedly ranges from , while the measurement from the gape to the tip of the bill is . The bill size is unusually variable: Alaskan eagles can have up to twice the bill length of birds from the southern United States (Georgia, Louisiana, Florida), with means including both sexes of and in culmen length, respectively, from these two areas.
The call consists of weak staccato, chirping whistles, "kleek kik ik ik ik", somewhat similar in cadence to a gull's call. The calls of young birds tend to be more harsh and shrill than those of adults. Range. The bald eagle's natural range covers most of North America, including most of Canada, all of the continental United States, and northern Mexico. It is the only sea eagle endemic to North America. Occupying varied habitats from the bayous of Louisiana to the Sonoran Desert and the eastern deciduous forests of Quebec and New England, northern birds are migratory, while southern birds are resident, remaining on their breeding territory all year. At minimum population, in the 1950s, it was largely restricted to Alaska, the Aleutian Islands, northern and eastern Canada, and Florida. From 1966 to 2015 bald eagle numbers increased substantially throughout its winter and breeding ranges, and as of 2018 the species nests in every continental state and province in the United States and Canada. The majority of bald eagles in Canada are found along the British Columbia coast while large populations are found in the forests of Alberta, Saskatchewan, Manitoba and Ontario. Bald eagles also congregate in certain locations in winter. From November until February, one to two thousand birds winter in Squamish, British Columbia, about halfway between Vancouver and Whistler. In March 2024, bald eagles were found nesting in Toronto for the first time. The birds primarily gather along the Squamish and Cheakamus Rivers, attracted by the salmon spawning in the area. Similar congregations of wintering bald eagles at open lakes and rivers, wherein fish are readily available for hunting or scavenging, are observed in the northern United States.
It has occurred as a vagrant twice in Ireland; a juvenile was shot illegally in Fermanagh on January 11, 1973 (misidentified at first as a white-tailed eagle), and an exhausted juvenile was captured near Castleisland, County Kerry on November 15, 1987. There is also a record of it from Llyn Coron, Anglesey, in the United Kingdom, from October 17, 1978; the provenance of this individual eagle has remained in dispute. Habitat. The bald eagle occurs during its breeding season in virtually any kind of American wetland habitat such as seacoasts, rivers, large lakes or marshes or other large bodies of open water with an abundance of fish. Studies have shown a preference for bodies of water with a circumference greater than , and lakes with an area greater than are optimal for breeding bald eagles. The bald eagle typically requires old-growth and mature stands of coniferous or hardwood trees for perching, roosting, and nesting. Tree species reportedly is less important to the eagle pair than the tree's height, composition and location. Perhaps of paramount importance for this species is an abundance of comparatively large trees surrounding the body of water. Selected trees must have good visibility, be over tall, an open structure, and proximity to prey. If nesting trees are in standing water such as in a mangrove swamp, the nest can be located fairly low, at as low as above the ground. In a more typical tree standing on dry ground, nests may be located from in height. In Chesapeake Bay, nesting trees averaged in diameter and in total height, while in Florida, the average nesting tree stands high and is in diameter. Trees used for nesting in the Greater Yellowstone area average high. Trees or forest used for nesting should have a canopy cover of no more than 60%, and no less than 20%, and be in close proximity to water. Most nests have been found within of open water. The greatest distance from open water recorded for a bald eagle nest was over , in Florida.
Bald eagle nests are often very large in order to compensate for size of the birds. The largest recorded nest was found in Florida in 1963, and was measured at wide and deep. In Florida, nesting habitats often consist of mangrove swamps, the shorelines of lakes and rivers, pinelands, seasonally flooded flatwoods, hardwood swamps, and open prairies and pastureland with scattered tall trees. Favored nesting trees in Florida are slash pines ("Pinus elliottii"), longleaf pines ("P. palustris"), loblolly pines ("P. taeda") and cypress trees, but for the southern coastal areas where mangroves are usually used. In Wyoming, groves of mature cottonwoods or tall pines found along streams and rivers are typical bald eagle nesting habitats. Wyoming eagles may inhabit habitat types ranging from large, old-growth stands of ponderosa pines ("Pinus ponderosa") to narrow strips of riparian trees surrounded by rangeland. In Southeast Alaska, Sitka spruce ("Picea sitchensis") provided 78% of the nesting trees used by eagles, followed by hemlocks ("Tsuga") at 20%. Increasingly, eagles nest in human-made reservoirs stocked with fish.
The bald eagle is usually quite sensitive to human activity while nesting, and is found most commonly in areas with minimal human disturbance. It chooses sites more than from low-density human disturbance and more than from medium- to high-density human disturbance. However, bald eagles will occasionally nest in large estuaries or secluded groves within major cities, such as Hardtack Island on the Willamette River in Portland, Oregon or John Heinz National Wildlife Refuge at Tinicum in Philadelphia, Pennsylvania, which are surrounded by a great quantity of human activity. Even more contrary to the usual sensitivity to disturbance, a family of bald eagles moved to the Harlem neighborhood in New York City in 2010. While wintering, bald eagles tend to be less habitat and disturbance sensitive. They will commonly congregate at spots with plentiful perches and waters with plentiful prey and (in northern climes) partially unfrozen waters. Alternately, non-breeding or wintering bald eagles, particularly in areas with a lack of human disturbance, spend their time in various upland, terrestrial habitats sometimes quite far away from waterways. In the northern half of North America (especially the interior portion), this terrestrial inhabitance by bald eagles tends to be especially prevalent because unfrozen water may not be accessible. Upland wintering habitats often consist of open habitats with concentrations of medium-sized mammals, such as prairies, meadows or tundra, or open forests with regular carrion access.
Behavior. The bald eagle is a powerful flier, and soars on thermal convection currents. It reaches speeds of when gliding and flapping, and about while carrying fish. Its dive speed is between , though it seldom dives vertically. Regarding their flying abilities, despite being morphologically less well adapted to faster flight than golden eagles (especially during dives), the bald eagle is considered surprisingly maneuverable in flight. Bald eagles have also been recorded catching up to and then swooping under geese in flight, turning over and thrusting their talons into the other bird's breast. It is partially migratory, depending on location. If its territory has access to open water, it remains there year-round, but if the body of water freezes during the winter, making it impossible to obtain food, it migrates to the south or to the coast. A number of populations are subject to post-breeding dispersal, mainly in juveniles; Florida eagles, for example, will disperse northwards in the summer. The bald eagle selects migration routes which take advantage of thermals, updrafts, and food resources. During migration, it may ascend in a thermal and then glide down, or may ascend in updrafts created by the wind against a cliff or other terrain. Migration generally takes place during the daytime, usually between the local hours of 8:00 a.m. and 6:00 p.m., when thermals are produced by the sun.
Diet and feeding. The bald eagle is an opportunistic carnivore with the capacity to consume a great variety of prey. Fish often comprise most of the eagle's diet throughout their range. In 20 food habit studies across the species' range, fish comprised 56% of the diet of nesting eagles, birds 28%, mammals 14% and other prey 2%. More than 400 species are known to be included in the bald eagle's prey spectrum, far more than its ecological equivalent in the Old World, the white-tailed eagle, is known to take. Despite its considerably lower population, the bald eagle may come in second amongst all North American accipitrids, slightly behind only the red-tailed hawk, in number of prey species recorded. Behavior.
They obtain much of their food as carrion or via a practice known as kleptoparasitism, by which they steal prey away from other predators. Due to their dietary habits, bald eagles are frequently viewed in a negative light by humans. Thanks to their superior foraging ability and experience, adults are generally more likely to hunt live prey than immature eagles, which often obtain their food from scavenging. They are not very selective about the condition or origin, whether provided by humans, other animals, auto accidents or natural causes, of a carcass's presence, but will avoid eating carrion where disturbances from humans are a regular occurrence. They will scavenge carcasses up to the size of whales, though carcasses of ungulates and large fish are seemingly preferred. Congregated wintering waterfowl are frequently exploited for carcasses to scavenge by immature eagles in harsh winter weather. Bald eagles also may sometimes feed on material scavenged or stolen from campsites and picnics, as well as garbage dumps (dump usage is habitual mainly in Alaska) and fish-processing plants.
Fish. In Southeast Alaska, fish comprise approximately 66% of the year-round diet of bald eagles and 78% of the prey brought to the nest by the parents. Eagles living in the Columbia River Estuary in Oregon were found to rely on fish for 90% of their dietary intake. At least 100 species of fish have been recorded in the bald eagle's diet. From observation in the Columbia River, 58% of the fish were caught alive by the eagle, 24% were scavenged as carcasses and 18% were pirated away from other animals. In the Pacific Northwest, spawning trout and salmon provide most of the bald eagles' diet from late summer throughout fall. Though bald eagles occasionally catch live salmon, they usually scavenge spawned salmon carcass. Southeast Alaskan eagles largely prey on pink salmon ("Oncorhynchus gorbuscha"), coho salmon ("O. kisutch") and, more locally, sockeye salmon ("O. nerka"), with Chinook salmon ("O. tshawytscha"). Due to the Chinook salmon's large size ( average adult size) probably being taken only as carrion and a single carcass can attract several eagles.
tshawytscha"). Due to the Chinook salmon's large size ( average adult size) probably being taken only as carrion and a single carcass can attract several eagles. Also important in the estuaries and shallow coastlines of southern Alaska are Pacific herring ("Clupea pallasii"), Pacific sand lance ("Ammodytes hexapterus") and eulachon ("Thaleichthys pacificus"). In Oregon's Columbia River Estuary, the most significant prey species were largescale suckers ("Catostomus macrocheilus") (17.3% of the prey selected there), American shad ("Alosa sapidissima"; 13%) and common carp ("Cyprinus carpio"; 10.8%). Eagles living in the Chesapeake Bay in Maryland were found to subsist largely on American gizzard shad ("Dorosoma cepedianum"), threadfin shad ("Dorosoma petenense") and white bass ("Morone chrysops"). Floridian eagles have been reported to prey on catfish, most prevalently the brown bullhead ("Ameiurus nebulosus") and any species in the genus "Ictalurus" as well as mullet, trout, needlefish, and eels. Chain pickerels ("Esox niger") and white suckers ("Catostomus commersonii") are frequently taken in interior Maine.
Chain pickerels ("Esox niger") and white suckers ("Catostomus commersonii") are frequently taken in interior Maine. Wintering eagles on the Platte River in Nebraska preyed mainly on American gizzard shads and common carp. Bald eagles are also known to eat the following fish species: rainbow trout ("Oncorhynchus mykiss"), white catfish ("Ameiurus catus"), rock greenling ("Hexagrammos lagocephalus"), Pacific cod ("Gadus macrocephalus"), Atka mackerel ("Pleurogrammus monopterygius"), largemouth bass ("Micropterus salmoides"), northern pike ("Esox lucius"), striped bass ("Morone saxatilis"), dogfish shark ("Squalidae.sp") and Blue walleye ("Sander vitreus"). Fish taken by bald eagles varies in size, but bald eagles take larger fish than other piscivorous birds in North America, typically range from and prefer fish. When experimenters offered fish of different sizes in the breeding season around Lake Britton in California, fish measuring were taken 71.8% of the time by parent eagles while fish measuring were chosen only 25% of the time. At nests around Lake Superior, the remains of fish (mostly suckers) were found to average in total length. In the Columbia River estuary, most preyed on by eagles were estimated to measure less than , but larger fish between or even exceeding in length also taken especially during the non-breeding seasons. They can take fish up to at least twice their own weight, such as large mature salmons, carps, or even muskellunge ("Esox masquinongy"), by dragging its catch with talons and pull toward ashore. Much larger marine fish such as Pacific halibut ("Hippoglossus stenolepis") and lemon sharks ("Negaprion brevirostris") have been recorded among bald eagle prey though probably are only taken as young, as small, newly mature fish, or as carrion.
Benthic fishes such as catfish are usually consumed after they die and float to the surface, though while temporarily swimming in the open may be more vulnerable to predation than most fish since their eyes focus downwards. Bald eagles also regularly exploit water turbines which produce battered, stunned or dead fish easily consumed. Predators who leave behind scraps of dead fish that they kill, such as brown bears ("Ursus arctos"), gray wolves ("Canis lupus") and red foxes ("Vulpes vulpes"), may be habitually followed in order to scavenge the kills secondarily. Once North Pacific salmon die off after spawning, usually local bald eagles eat salmon carcasses almost exclusively. Eagles in Washington need to consume of fish each day for survival, with adults generally consuming more than juveniles and thus reducing potential energy deficiency and increasing survival during winter. Birds. Behind fish, the next most significant prey base for bald eagles are other waterbirds. The contribution of such birds to the eagle's diet is variable, depending on the quantity and availability of fish near the water's surface. Waterbirds can seasonally comprise from 7% to 80% of the prey selection for eagles in certain localities. Overall, birds are the most diverse group in the bald eagle's prey spectrum, with 200 prey species recorded.
Bird species most preferred as prey by eagles tend to be medium-sized, such as western grebes ("Aechmophorus occidentalis"), mallards ("Anas platyrhynchos"), and American coots ("Fulica americana") as such prey is relatively easy for the much larger eagles to catch and fly with. American herring gull ("Larus smithsonianus") are the favored avian prey species for eagles living around Lake Superior. Black ducks ("Anas rubripes"), common eiders ("Somateria mollissima"), and double-crested cormorants ("Phalacrocorax auritus") are also frequently taken in coastal Maine and velvet scoter ("Melanitta fusca") was dominant prey in San Miguel Island. Due to easy accessibility and lack of formidable nest defense against eagles by such species, bald eagles are capable of preying on such seabirds at all ages, from eggs to mature adults, and they can effectively cull large portions of a colony. Along some portions of the North Pacific coastline, bald eagles which had historically preyed mainly kelp-dwelling fish and supplementally sea otter ("Enhydra lutris") pups are now preying mainly on seabird colonies since both the fish (possibly due to overfishing) and otters (cause unknown) have had steep population declines, causing concern for seabird conservation. Because of this more extensive predation, some biologist has expressed concern that murres are heading for a "conservation collision" due to heavy eagle predation. Eagles have been confirmed to attack nocturnally active, burrow-nesting seabird species such as storm petrels and shearwaters by digging out their burrows and feeding on all animals they find inside. If a bald eagle flies close by, waterbirds will often fly away en masse, though they may seemingly ignore a perched eagle in other cases. when the birds fly away from a colony, this exposes their unprotected eggs and nestlings to scavengers such as gulls.
While they usually target small to medium-sized seabirds, larger seabirds such as great black-backed gulls ("Larus marinus") and northern gannets ("Morus bassanus") and brown pelicans ("Pelecanus occidentalis") of all ages can successfully be taken by bald eagles. Similarly, large waterbirds are occasionally killed. Geese such as wintering emperor geese ("Chen canagica") and snow geese ("C. caerulescens"), which gather in large groups, sometimes becoming regular prey. Smaller Ross's geese ("Anser rossii") are also taken, as well as large-sized Canada geese ("Branta canadensis"). Predation on the largest subspecies ("Branta canadensis maxima") has been reported. Other large waterbird prey include common loons ("Gavia immer") of all ages. Large wading birds can also fall prey to bald eagles. For the great blue herons ("Ardea herodias"), bald eagles are their only serious enemies of all ages. Slightly larger Sandhill cranes ("Grus canadensis") can be taken as well. While adult whooping cranes ("Grus americana") are too large and formidable, their chicks can fall prey to bald eagles. They even occasionally prey on adult tundra swans ("Cygnus columbianus"). Young trumpeter swans ("Cygnus buccinator") are also taken, and an unsuccessful attack on an adult swan has been photographed.
Bald eagles have been occasionally recorded as killing other raptors. In some cases, these may be attacks of competition or kleptoparasitism on rival species but end with the consumption of the dead victims. Nine species of other accipitrids and owls are known to have been preyed upon by bald eagles. Owl prey species have ranged in size from western screech-owls ("Megascops kennicotti") to snowy owls ("Bubo scandiacus"). Larger diurnal raptors known to have fallen victim to bald eagles have included red-tailed hawks ("Buteo jamaicensis"), peregrine falcons ("Falco peregrinus"), northern goshawks ("Accipiter gentilis"), ospreys ("Pandion haliaetus") and black ("Coragyps atratus") and turkey vultures ("Cathartes aura"). Mammals. Mammalian preys are generally less frequently taken than fish or avian prey. However, in some regions, such as landlocked areas of North America, wintering bald eagles may become habitual predators of medium-sized mammals that occur in colonies or local concentrations, such as prairie dogs ("Cynomys" sp.) and jackrabbits ("Lepus" sp.). Bald eagles in Seedskadee National Wildlife Refuge often hunt in pair to catch cottontails, jackrabbits and prairie dogs. They can attack and prey on rabbits and hares of nearly any size, from marsh rabbits ("Sylvilagus palustris") to black and white-tailed jackrabbits ("Lepus californicus" & "L. townsendii"), and Arctic hares ("Lepus arcticus"). In San Luis Valley, white-tailed jackrabbits can be important prey. Additionally, rodents such as montane voles ("Microtus montanus"), brown rats ("Rattus norvegicus"), and various squirrels are taken as supplementary prey. Larger rodents such as muskrats ("Ondatra zibethicus"), young or small adult nutrias ("Myocastor coypus") and groundhogs ("Marmota monax") are also preyed upon. Even American porcupines ("Erethizon dorsatum") are reportedly attacked and killed.
Where available, seal colonies can provide a lot of food. On Protection Island, Washington, they commonly feed on harbor seal ("Phoca vitulina") afterbirths, still-borns and sickly seal pups. Similarly, bald eagles in Alaska readily prey on sea otter ("Enhydra lutris") pups. Small to medium-sized terrestrial mammalian carnivores can be taken infrequently. Mustelid including American martens ("Martes pennanti"), American minks ("Neogale vison"), and larger fisher cats ("Pekania pennanti") are known to be hunted. Foxes are also taken, including Island foxes (" Urocyon littoralis "), Arctic foxes ("Vulpes lagopus"), and grey foxes ("Urocyon cinereoargenteus"). Although fox farmers claimed that bald eagle heavily prey on young and adult free-range Arctic fox, the predation events are sporadic. In one instance, two bald Eagles fed upon a red fox ("Vulpes vulpes") that had tried to cross a frozen Delaware Lake. Other medium-sized carnivorans such as striped skunks ("Mephitis mephitis"), American hog-nosed skunks ("Conepatus leuconotus"), and common raccoons ("Procyon lotor") are taken, as well as domestic cats ("Felis catus") and dogs ("canis familiaris").
Other wild mammalian prey include fawns of deer such as white-tailed deer ("Odocoileus virginianus") and Sitka deer ("Odocoileus hemionus sitkensis"), which weigh around can be taken alive by bald eagles. In one instance, a bald eagle was observed carrying mule deer ("Odocoileus hemionus") fawn. Additionally, Virginia opossums ("Didelphis virginiana") can be preyed upon. Still, predation events are rare due to their nocturnal habits. Together with the golden eagle, bald eagles are occasionally accused of preying on livestock, especially sheep ("Ovis aries"). There are a handful of proven cases of lamb predation, some specimens weighing up to , by bald eagles. Still, they are much less likely to attack a healthy lamb than a golden eagle. Both species prefer native, wild prey and are unlikely to cause any extensive detriment to human livelihoods. There is one case of a bald eagle killing and feeding on an adult, pregnant ewe (then joined in eating the kill by at least 3 other eagles), which, weighing on average over , is much larger than any other known prey taken by this species.
Reptiles and other prey. Supplemental prey is readily taken given the opportunity. In some areas, reptiles may become regular prey, especially in warm areas such as Florida where reptile diversity is high. Turtles are perhaps the most regularly hunted type of reptile. In coastal New Jersey, 14 of 20 studied eagle nests included remains of turtles. The main species found were common musk turtles ("Sternotherus odoratus"), diamondback terrapin ("Malaclemys terrapin") and juvenile common snapping turtles ("Chelydra serpentina"). In these New Jersey nests, mainly subadult and small adults were taken, ranging in carapace length from . Similarly, many turtles were recorded in the diet in the Chesapeake Bay. In Texas, softshell turtles are the most frequently taken prey, and a large number of Barbour's map turtles are taken in Torreya State Park. Other reptilian and amphibian prey includes southern alligator lizards ("Elgaria multicarinata"), snakes such as garter snakes and rattlesnakes, and Greater siren ("Siren lacertina").
Invertebrates are occasionally taken. In Alaska, eagles feed on sea urchins ("Strongylocentrotus" sp.), chitons, mussels, and crabs. Other various mollusks such as land snails, abalones, bivalves, periwinkles, blue mussels, squids, and starfishes are taken as well. Interspecific predatory relationships. When competing for food, eagles will usually dominate other fish-eaters and scavengers, aggressively displacing mammals such as coyotes ("Canis latrans") and foxes, and birds such as corvids, gulls, vultures and other raptors. Occasionally, coyotes, bobcats ("Lynx rufus") and domestic dogs ("Canis familiaris") can displace eagles from carrion, usually less confident immature birds, as has been recorded in Maine. Bald eagles are less active, bold predators than golden eagles and get relatively more of their food as carrion and from kleptoparasitism (although it is now generally thought that golden eagles eat more carrion than was previously assumed). However, the two species are roughly equal in size, aggressiveness and physical strength and so competitions can go either way. Neither species is known to be dominant, and the outcome depends on the size and disposition of the individual eagles involved. Wintering bald and golden eagles in Utah both sometimes won conflicts, though in one recorded instance a single bald eagle successfully displaced two consecutive golden eagles from a kill.
Though bald eagles face few natural threats, an unusual attacker comes in the form of the common loon ("G. immer"), which is also taken by eagles as prey. While common loons normally avoid conflict, they are highly territorial and will attack predators and competitors by stabbing at them with their knife-like bill; as the range of the bald eagle has increased following conservation efforts, these interactions have been observed on several occasions, including a fatality of a bald eagle in Maine that is presumed to have come about as a result of it attacking a nest, then having a fatal puncture wound inflicted by one or both loon parents. The bald eagle is thought to be much more numerous in North America than the golden eagle, with the bald species estimated to number at least 150,000 individuals, about twice as many as there are golden eagles estimated to live in North America. Due to this, bald eagles often outnumber golden eagles at attractive food sources. Despite the potential for contention between these animals, in New Jersey during winter, a golden eagle and numerous bald eagles were observed to hunt snow geese alongside each other without conflict.
Despite the potential for contention between these animals, in New Jersey during winter, a golden eagle and numerous bald eagles were observed to hunt snow geese alongside each other without conflict. Similarly, both eagle species have been recorded, via video-monitoring, to feed on gut piles and carcasses of white-tailed deer ("Odocoileus virginianus") in remote forest clearings in the eastern Appalachian Mountains without apparent conflict. Bald eagles are frequently mobbed by smaller raptors, due to their infrequent but unpredictable tendency to hunt other birds of prey. Many bald eagles are habitual kleptoparasites, especially in winters when fish are harder to come by. They have been recorded stealing fish from other predators such as ospreys, herons and even otters. They have also been recorded opportunistically pirating birds from peregrine falcons ("Falco peregrinus"), prairie dogs from ferruginous hawks ("Buteo regalis") and even jackrabbits from golden eagles. When they approach scavengers such as dogs, gulls or vultures at carrion sites, they often attack them in an attempt to force them to disgorge their food. When they approach scavengers such as dogs, gulls or vultures at carrion sites, they often attack them in an attempt to force them to disgorge their food. Healthy adult bald eagles are not preyed upon in the wild and are thus considered apex predators.
Reproduction. Bald eagles are sexually mature at four or five years of age. When they are old enough to breed, they often return to the area where they were born. Bald eagles have high mate fidelity and generally mate for life. However, if one pair member dies or disappears, the survivor will choose a new mate. A pair that has repeatedly failed in breeding attempts may split and look for new mates. Bald eagle courtship involves elaborate, spectacular calls and flight displays by the males. The flight includes swoops, chases, and cartwheels, in which they fly high, lock talons, and free-fall, separating just before hitting the ground. Usually, a territory defended by a mature pair will be of waterside habitat. Compared to most other raptors, which mostly nest in April or May, bald eagles are early breeders: nest building or reinforcing is often by mid-February, egg laying is often late February (sometimes during deep snow in the North), and incubation is usually mid-March and early May. Eggs hatch from mid-April to early May, and the young fledge from late June to early July. The nest is the largest of any bird in North America; it is used repeatedly over many years and with new material added each year may eventually be as large as deep, across and weigh . One nest in Florida was found to be deep, across, and to weigh . This nest is on record as the largest tree nest ever recorded for any animal. Usually nests are used for under five years, as they either collapse in storms or break the branches supporting them by their sheer weight. However, one nest in the Midwest was occupied continuously for at least 34 years. The nest is built of branches, usually in large trees found near water. When breeding where there are no trees, the bald eagle will nest on the ground, as has been recorded largely in areas largely isolated from terrestrial predators, such as Amchitka Island in Alaska.
In Sonora, Mexico, eagles have been observed nesting on top of hecho catcuses ("Pachycereus pectin-aboriginum"). Nests located on cliffs and rock pinnacles have been reported historically in California, Kansas, Nevada, New Mexico and Utah, but currently are only verified to occur only in Alaska and Arizona. The eggs average about long, ranging from , and have a breadth of , ranging from . Eggs in Alaska averaged in mass, while in Saskatchewan they averaged . As with their ultimate body size, egg size tends to increase with distance from the equator. Eagles produce between one and three eggs per year, two being typical. Rarely, four eggs have been found in nests, but these may be exceptional cases of polygyny. Eagles in captivity have been capable of producing up to seven eggs. It is rare for all three chicks to successfully reach the fledgling stage. The oldest chick often bears the advantage of a larger size and louder voice, which tends to draw the parents' attention towards it. Occasionally, as is recorded in many large raptorial birds, the oldest sibling sometimes attacks and kills its younger sibling(s), especially early in the nesting period when their sizes are most different. However, nearly half of the known bald eagles produce two fledglings (more rarely three), unlike in some other "eagle" species such as some in the genus "Aquila", in which a second fledgling is typically observed in less than 20% of nests, despite two eggs typically being laid. Both the male and female take turns incubating the eggs, but the female does most of the sitting. The parent not incubating will hunt for food or look for nesting material during this stage. For the first two to three weeks of the nestling period, at least one adult is at the nest almost 100% of the time. After five to six weeks, the attendance of parents usually drops off considerably (with the parents often perching in trees nearby).
A young eaglet can gain up to a day, the fastest growth rate of any North American bird. The young eaglets pick up and manipulate sticks, play tug of war with each other, practice holding things in their talons, and stretch and flap their wings. By eight weeks, the eaglets are strong enough to flap their wings, lift their feet off the nest platform, and rise in the air. The young fledge at anywhere from 8 to 14 weeks of age, though will remain close to the nest and be attended to by their parents for a further 6 weeks. Juvenile eagles first start dispersing away from their parents about 8 weeks after they fledge. Variability in departure date related to effects of sex and hatching order on growth and development. For the next four years, immature eagles wander widely in search of food until they attain adult plumage and are eligible to reproduce. Male eagles have been observed killing and cannibalizing their chicks. In 2024 at the National Conservation Training Center in West Virginia, the NCTC's Eagle Cam recorded two bald eagle chicks being attacked and devoured by their father as soon as the mother departed from the nest. The NCTC noted in its statement on the incident that such behavior "has been observed in other nests and is not uncommon in birds of prey."
On rare occasions, bald eagles have been recorded to adopt other raptor fledglings into their nests, as seen in 2017 by a pair of eagles in Shoal Harbor Migratory Bird Sanctuary near Sidney, British Columbia. The pair of eagles in question are believed to have carried a juvenile red-tailed hawk back to their nest, presumably as prey, whereupon the chick was accepted into the family by both the parents and the eagles' three nestlings. The hawk, nicknamed "Spunky" by biologists monitoring the nest, fledged successfully. Longevity and mortality. The average lifespan of bald eagles in the wild is around 20 years, with the oldest confirmed one having been 38 years of age. In captivity, they often live somewhat longer. In one instance, a captive individual in New York lived for nearly 50 years. As with size, the average lifespan of an eagle population appears to be influenced by its location and access to prey. As they are no longer heavily persecuted, adult mortality is quite low. In one study of Florida eagles, adult bald eagles reportedly had 100% annual survival rate.
As they are no longer heavily persecuted, adult mortality is quite low. In one study of Florida eagles, adult bald eagles reportedly had 100% annual survival rate. In Prince William Sound in Alaska, adults had an annual survival rate of 88% even after the Exxon Valdez oil spill adversely affected eagles in the area. Of 1,428 individuals from across the range necropsied by National Wildlife Health Center from 1963 to 1984, 329 (23%) eagles died from trauma, primarily impact with wires and vehicles; 309 (22%) died from gunshot; 158 (11%) died from poisoning; 130 (9%) died from electrocution; 68 (5%) died from trapping; 110 (8%) from emaciation; and 31 (2%) from disease; cause of death was undetermined in 293 (20%) of cases. In this study, 68% of mortality was human-caused. Today, eagle-shooting is believed to be considerably reduced due to the species' protected status. A U.S.
Most non-human-related mortality involves nestlings or eggs. Around 50% of eagles survive their first year. However, in the Chesapeake Bay area, 100% of 39 radio-tagged nestlings survived to their first year. Nestling or egg fatalities may be due to nest collapses, starvation, sibling aggression or inclement weather. Another significant cause of egg and nestling mortality is predation. Nest predators include large gulls, corvids (including ravens, crows and magpies), wolverines ("Gulo gulo"), fishers ("Pekania pennanti"), red-tailed hawks, owls, other eagles, bobcats, American black bears ("Ursus americanus") and raccoons. If food access is low, parental attendance at the nest may be lower because both parents may have to forage, thus resulting in less protection. Nestlings are usually exempt from predation by terrestrial carnivores that are poor tree-climbers, but Arctic foxes ("Vulpes lagopus") occasionally snatched nestlings from ground nests on Amchitka Island in Alaska before they were extirpated from the island. The bald eagle will defend its nest fiercely from all comers and has even repelled attacks from bears, having been recorded knocking a black bear out of a tree when the latter tried to climb a tree holding nestlings.
Relationship with humans. Population decline and recovery. Once a common sight in much of the continent, the bald eagle was severely affected in the mid-20th century by a variety of factors, among them the thinning of egg shells attributed to use of the pesticide DDT. Bald eagles, like many birds of prey, were especially affected by DDT due to biomagnification. DDT itself was not lethal to the adult bird, but it interfered with their calcium metabolism, making them either sterile or unable to lay healthy eggs; many of their eggs were too brittle to withstand the weight of a brooding adult, making it nearly impossible for them to hatch. It is estimated that in the early 18th century the bald eagle population was 300,000–500,000, but by the 1950s there were only 412 nesting pairs in the 48 contiguous states of the US. Other factors in bald eagle population reductions were a widespread loss of suitable habitat, as well as both legal and illegal shooting. In 1930 a New York City ornithologist wrote that in the territory of Alaska in the previous 12 years approximately 70,000 bald eagles had been shot. Many of the hunters killed the bald eagles under the long-held beliefs that bald eagles grabbed young lambs and even children with their talons, yet the birds were innocent of most of these alleged acts of predation (lamb predation is rare, human predation is thought to be non-existent). Illegal shooting was described as "the leading cause of direct mortality in both adult and immature bald eagles" by the U.S. Fish and Wildlife Service in 1978. Leading causes of death in bald eagles include lead pollution, poisoning, collision with motor vehicles, and power-line electrocution. A study published in 2022 in the journal Science found that more than half of adult eagles across 38 US states suffered from lead poisoning. The primary cause is when eagles scavenge carcasses of animals shot by hunters. These are often tainted with lead shotgun pellets, rifle rounds, or fishing tackle.
The species was first protected in the U.S. and Canada by the 1918 Migratory Bird Treaty, later extended to all of North America. The Bald and Golden Eagle Protection Act, approved by the U.S. Congress in 1940, protected the bald eagle and the golden eagle, prohibiting commercial trapping and killing of the birds as well as collecting their eggs. The bald eagle was declared an endangered species in the U.S. in 1967, and amendments to the 1940 act between 1962 and 1972 further restricted commercial uses and increased penalties for violators. Perhaps most significant in the species' recovery, in 1972, DDT was banned from usage in the United States due to the fact that it inhibited the reproduction of many birds. DDT was completely banned in Canada in 1989, though its use had been highly restricted since the late 1970s.
The bald eagle was officially removed from the U.S. federal government's list of endangered species on July 12, 1995, by the U.S. Fish & Wildlife Service, when it was reclassified from "endangered" to "threatened". On July 6, 1999, a proposal was initiated "To Remove the Bald Eagle in the Lower 48 States From the List of Endangered and Threatened Wildlife". It was de-listed on June 28, 2007. It has also been assigned a risk level of least concern category on the IUCN Red List. In the "Exxon Valdez" oil spill of 1989 an estimated 247 were killed in Prince William Sound, though the local population returned to its pre-spill level by 1995. In some areas, the increase in eagles has led to decreases in other bird populations and the eagles may be considered a pest. Killing permits. In December 2016, the U.S. Fish and Wildlife Service proposed extending the permits issued to wind generation companies to allow them to kill up to 4,200 bald eagles per year without facing a penalty, four times the previous number. The permits would last 30 years, six times the previous 5-year term.
In captivity. Permits are required to keep bald eagles in captivity in the United States. Permits are primarily issued to public educational institutions, and the eagles that they show are permanently injured individuals that cannot be released to the wild. The facilities where eagles are kept must be equipped with adequate caging, as well as workers experienced in the handling and care of eagles. The bald eagle can be long-lived in captivity if well cared for, but does not breed well even under the best conditions. In Canada and in England a license is required to keep bald eagles for falconry. Bald eagles cannot legally be kept for falconry in the United States, but a license may be issued in some jurisdictions to allow use of such eagles in birds-of-prey flight shows. Cultural significance. The bald eagle is important in various Native American cultures and, as the national symbol of the United States, is prominent in seals and logos, coinage, postage stamps, and other items relating to the U.S. federal government.
Role in Native American culture. The bald eagle is a sacred bird in some North American cultures, and its feathers, like those of the golden eagle, are central to many religious and spiritual customs among Native Americans. Eagles are considered spiritual messengers between gods and humans by some cultures. Many pow wow dancers use the eagle claw as part of their regalia as well. Eagle feathers are often used in traditional ceremonies, particularly in the construction of regalia worn and as a part of fans, bustles and head dresses. In the Navajo tradition an eagle feather is represented to be a protector, along with the feather Navajo medicine men use the leg and wing bones for ceremonial whistles. The Lakota, for instance, give an eagle feather as a symbol of honor to person who achieves a task. In modern times, it may be given on an event such as a graduation from college. The Pawnee consider eagles as symbols of fertility because their nests are built high off the ground and because they fiercely protect their young. The Choctaw consider the bald eagle, who has direct contact with the upper world of the sun, as a symbol of peace.
During the Sun Dance, which is practiced by many Plains Indian tribes, the eagle is represented in several ways. The eagle nest is represented by the fork of the lodge where the dance is held. A whistle made from the wing bone of an eagle is used during the course of the dance. Also during the dance, a medicine man may direct his fan, which is made of eagle feathers, to people who seek to be healed. The medicine man touches the fan to the center pole and then to the patient, in order to transmit power from the pole to the patient. The fan is then held up toward the sky, so that the eagle may carry the prayers for the sick to the Creator. Current eagle feather law stipulates that only individuals of certifiable Native American ancestry enrolled in a federally recognized tribe are legally authorized to obtain or possess bald or golden eagle feathers for religious or spiritual use. The constitutionality of these laws has been questioned by Native American groups on the basis that it violates the First Amendment by affecting ability to practice their religion freely.
The National Eagle Repository, a division of the FWS, exists as a means to receive, process, and store bald and golden eagles which are found dead and to distribute the eagles, their parts and feathers to federally recognized Native American tribes for use in religious ceremonies. National symbol of the United States. The bald eagle is the national symbol of the United States. It was adopted as a national emblem in 1782, but not designated the "national bird" until an act of Congress in December 2024. The founders of the United States were fond of comparing their new republic with the Roman Republic, in which eagle imagery (usually involving the golden eagle) was prominent. On June 20, 1782, the Continental Congress adopted the design for the Great Seal of the United States, depicting a bald eagle grasping 13 arrows and an olive branch with thirteen leaves with its talons. The bald eagle appears on most official seals of the U.S. government, including the presidential seal, the presidential flag, and in the logos of many U.S. federal agencies. Between 1916 and 1945, the presidential flag (but not the seal) showed an eagle facing to its left (the viewer's right), which gave rise to the urban legend that the flag is changed to have the eagle face towards the olive branch in peace, and towards the arrows in wartime.
Contrary to popular legend, there is no evidence that Benjamin Franklin ever publicly supported the wild turkey ("Meleagris gallopavo"), rather than the bald eagle, as a symbol of the United States. However, in a letter written to his daughter in 1784 from Paris, criticizing the Society of the Cincinnati, he stated his personal distaste for the bald eagle's behavior. In the letter Franklin states: Franklin opposed the creation of the Society because he viewed it, with its hereditary membership, as a noble order unwelcome in the newly independent Republic, contrary to the ideals of Lucius Quinctius Cincinnatus, for whom the Society was named. His reference to the two kinds of birds is interpreted as a satirical comparison between the Society of the Cincinnati and Cincinnatus. Popular culture. Largely because of its role as a symbol of the United States, but also because of its being a large predator, the bald eagle has many representations in popular culture. In film and television depictions the call of the red-tailed hawk, which is much louder and more powerful, is often substituted for bald eagles.
Brown bear The brown bear (Ursus arctos) is a large bear native to Eurasia and North America. Of the land carnivorans, it is rivaled in size only by its closest relative, the polar bear, which is much less variable in size and slightly bigger on average. The brown bear is a sexually dimorphic species, as adult males are larger and more compactly built than females. The fur ranges in color from cream to reddish to dark brown. It has evolved large hump muscles, unique among bears, and paws up to wide and long, to effectively dig through dirt. Its teeth are similar to those of other bears and reflect its dietary plasticity. Throughout the brown bear's range, it inhabits mainly forested habitats in elevations of up to . It is omnivorous, and consumes a variety of plant and animal species. Contrary to popular belief, the brown bear derives 90% of its diet from plants. When hunting, it will target animals as small as insects and rodents to those as large as moose or muskoxen. In parts of coastal Alaska, brown bears predominantly feed on spawning salmon that come near shore to lay their eggs. For most of the year, it is a usually solitary animal that associates only when mating or raising cubs. Females give birth to an average of one to three cubs that remain with their mother for 1.5 to 4.5 years. It is a long-lived animal, with an average lifespan of 25 years in the wild. Relative to its body size, the brown bear has an exceptionally large brain. This large brain allows for high cognitive abilities, such as tool use. Attacks on humans, though widely reported, are generally rare.
While the brown bear's range has shrunk, and it has faced local extinctions across its wide range, it remains listed as a least concern species by the International Union for Conservation of Nature (IUCN) with a total estimated population in 2017 of 110,000. Populations that were hunted to extinction in the 19th and 20th centuries are the Atlas bear of North Africa and the Californian, Ungavan and Mexican populations of the grizzly bear of North America. Many of the populations in the southern parts of Eurasia are highly endangered as well. One of the smaller-bodied forms, the Himalayan brown bear, is critically endangered: it occupies only 2% of its former range and is threatened by uncontrolled poaching for its body parts. The Marsican brown bear of central Italy is one of several currently isolated populations of the Eurasian brown bear and is believed to have a population of only about 50 bears. The brown bear is considered to be one of the most popular of the world's charismatic megafauna. It has been kept in zoos since ancient times, and has been tamed and trained to perform in circuses and other acts. For thousands of years, the brown bear has had a role in human culture, and is often featured in literature, art, folklore, and mythology.
Etymology. The brown bear is sometimes referred to as the , from Middle English. This name originated in the fable "History of Reynard the Fox", translated by William Caxton, from the Middle Dutch word or , meaning "brown". In the mid-19th-century United States, the brown bear was given the nicknames "Old Ephraim" and "Moccasin Joe". The scientific name of the brown bear, "Ursus arctos", comes from the Latin , meaning "bear", and the Greek /, also meaning "bear". Evolution and taxonomy. Taxonomy and subspecies. Carl Linnaeus scientifically described the species under the name "Ursus arctos" in the 1758 edition of "Systema Naturae". Brown bear taxonomy and subspecies classification has been described as "formidable and confusing", with few authorities listing the same set of subspecies. There are hundreds of obsolete brown-bear subspecies. As many as 90 subspecies have been proposed. A 2008 DNA analysis identified as few as five main clades, which comprise all extant brown bear species, while a 2017 phylogenetic study revealed nine clades, including one representing polar bears. , 15 extant, or recently extinct, subspecies were recognized by the general scientific community.
DNA analysis shows that, apart from recent, human-caused population fragmentation, brown bears in North America are generally part of a single interconnected population system, with the exception of the population (or subspecies) in the Kodiak Archipelago, which has probably been isolated since the end of the last Ice Age. These data demonstrate that "U. a. gyas", "U. a. horribilis", "U. a. sitkensis", and "U. a. stikeenensis" are not distinct or cohesive groups, and would more accurately be described as ecotypes. For example, brown bears in any particular region of the Alaska coast are more closely related to adjacent grizzly bears than to distant populations of brown bears. The history of the bears of the Alexander Archipelago is unusual in that these island populations carry polar bear DNA, presumably originating from a population of polar bears that was left behind at the end of the Pleistocene, but have since been connected with adjacent mainland populations through the movement of males, to the point where their nuclear genomes indicate more than 90% brown bear ancestry. MtDNA analysis revealed that brown bears are apparently divided into five different clades, some of which coexist or co-occur in different regions.
Evolution. The brown bear is one of eight extant species in the bear family Ursidae and of six extant species in the subfamily Ursinae. The brown bear is thought to have evolved from the Etruscan bear ("Ursus etruscus") in Asia during the early Pliocene. A genetic analysis indicated that the brown bear lineage diverged from the cave bear species-complex approximately 1.2–1.4 million years ago, but did not clarify if "U. savini" persisted as a paraspecies for the brown bear before perishing. The oldest brown bear fossils occur in Asia from about 500,000 to 300,000 years ago. They entered Europe 250,000 years ago and North Africa shortly after. Brown bear remains from the Pleistocene period are common in the British Isles, where, amongst other factors, they may have contributed to the extinction of cave bears ("Ursus spelaeus"). Brown bears first emigrated to North America from Eurasia via Beringia during the Illinoian Glaciation. Genetic evidence suggests that several brown bear populations migrated into North America, aligning with the glacial cycles of the Pleistocene. The founding population of most North American brown bears arrived first, with the genetic lineage developing around ~177,000 BP. Genetic divergences suggest that brown bears first migrated south during MIS-5 (~92,000–83,000 BP), upon the opening of the ice-free corridor, After a local extinction in Beringia ~33,000 BP, two new but closely related lineages repopulated Alaska and northern Canada from Eurasia after the Last Glacial Maximum (>25,000 BP).
Brown-bear fossils discovered in Ontario, Ohio, Kentucky, and Labrador show that the species occurred farther east than indicated in historic records. In North America, two types of the subspecies "Ursus arctos horribilis" are generally recognized—the coastal brown bear and the inland grizzly bear. Hybrids. A grizzly–polar bear hybrid is a rare ursid hybrid resulting from a crossbreeding of a brown bear with a polar bear. It has occurred both in captivity and in the wild. In 2006, the occurrence of this hybrid was confirmed by testing the DNA of a strange-looking bear that had been shot in the Canadian Arctic, and seven more hybrids have since been confirmed in the same region, all descended from a single female polar bear. Previously, the hybrid had been produced in zoos and was considered a "cryptid" (a hypothesized animal for which there is no scientific proof of existence in the wild). Analyses of the genomes of bears have shown that introgression between species was widespread during the evolution of the genus "Ursus", including the introgression of polar-bear DNA introduced to brown bears during the Pleistocene.
Description. Size. The brown bear is the most variable in size of modern bears. The typical size depends upon which population it is from, as most accepted subtypes vary widely in size. This is in part due to sexual dimorphism, as male brown bears average at least 30% larger than females in most subtypes. Individual bears vary in size seasonally, weighing the least in spring due to lack of foraging during hibernation, and the most in late fall, after a period of hyperphagia to put on additional weight to prepare for hibernation. Brown bears generally weigh , with males outweighing females. They have a head-and-body length of and a shoulder height of . The tail is relatively short, as in all bears, ranging from in length. The smallest brown bears, females during spring among barren-ground populations, can weigh so little as to roughly match the body mass of males of the smallest living bear species, the sun bear ("Helarctos malayanus"), while the largest coastal populations attain sizes broadly similar to those of the largest living bear species, the polar bear. Brown bears of the interior are generally smaller, being around the same weight as an average lion, at an average of in males and in females, whereas adults of the coastal populations weigh about twice as much. The average weight of adult male bears, from 19 populations, was found to be while adult females from 24 populations were found to average .
Coloration. Brown bears are often not fully brown. They have long, thick fur, with a moderately elongated mane at the back of the neck which varies somewhat across bear types. In India, brown bears can be reddish with silver-tipped hairs, while in China, brown bears are bicolored, with a yellowish-brown or whitish collar across the neck, chest, and shoulders. Even within well-defined subspecies, individuals may show highly variable hues of brown. North American grizzlies can be from dark brown (almost black) to cream (almost white) or yellowish-brown and often have darker-colored legs. The common name "grizzly" stems from their typical coloration, with the hairs on their back usually being brownish-black at the base and whitish-cream at the tips, giving them their distinctive "grizzled" color. Apart from the cinnamon subspecies of the American black bear ("U. americanus cinnamonum"), the brown bear is the only modern bear species to typically appear truly brown. The brown bear's winter fur is very thick and long, especially in northern subspecies, and can reach at the withers. The winter hairs are thin, yet rough to the touch. The summer fur is much shorter and sparser, with its length and density varying among geographic ranges.
Cranial morphology and size. Adults have massive, heavily built, concave skulls, which are large in proportion to the body. The projections of the skull are well developed. Skull lengths of Russian brown bears tend to be for males, and for females. Brown bears have the broadest skull of any extant ursine bear. The width of the zygomatic arches in males is , and in females. Brown bears have strong jaws: the incisors and canine teeth are large, with the lower canines being strongly curved. The first three molars of the upper jaw are underdeveloped and single-crowned with one root. The second upper molar is smaller than the others, and is usually absent in adults. It is usually lost at an early age, leaving no trace of its alveolus in the jaw. The first three molars of the lower jaw are very weak, and are often lost at an early age. The teeth of brown bears reflect their dietary plasticity and are broadly similar to those of other bears. They are reliably larger than teeth of American black bears, but average smaller in molar length than those of polar bears.
Claws and feet. Brown bears have large, curved claws, with the front ones being larger than the back. They may reach and measure along the curve. Compared with the American black bear ("Ursus americanus"), the brown bear has longer and stronger claws, with a blunt curve. Due to their claw structure, in addition to their excessive weight, adult brown bears are not able to climb trees as well as black bears. In rare cases adult female brown bears have been seen scaling trees. The claws of a polar bear are quite different, being notably shorter but broader with a strong curve and sharper point. The species has large paws; the rear feet measure long, while the forefeet tend to measure 40% less. Brown bears are the only extant bears with a hump at the top of their shoulder, which is made entirely of muscle. This feature developed presumably to impart more force in digging, which helps during foraging and facilitates den construction prior to hibernation. Distribution and habitat. Brown bears inhabit the broadest range of habitats of any living bear species. They seem to have no altitudinal preferences and have been recorded from sea level to an elevation of in the Himalayas. In most of their range, brown bears seem to prefer semi-open country, with a scattering of vegetation, that can allow them a resting spot during the day. However, they have been recorded as inhabiting every variety of northern temperate forest known to occur.
This species was once native to Europe, much of Asia, the Atlas Mountains of Africa, and North America, but are now extirpated in some areas, and their populations have greatly decreased in other areas. There are approximately 200,000 brown bears left in the world. The largest populations are in Russia with 130,000, the United States with 32,500, and Canada with around 25,000. Brown bears live in Alaska, east through the Yukon and Northwest Territories, south through British Columbia, and through the western half of Alberta. The Alaskan population is estimated at a healthy 30,000 individuals. In the lower 48 states, they are repopulating slowly, but steadily along the Rockies and the western Great Plains. In Europe, in 2010, there were 14,000 brown bears in ten fragmented populations, from Spain (estimated at only 20–25 animals in the Pyrenees in 2010, in a range shared between Spain, France, and Andorra, and some 210 animals in Asturias, Cantabria, Galicia, and León, in the Picos de Europa and adjacent areas in 2013) in the west, to Russia in the east, and from Sweden and Finland in the north to Romania (5,000–6,000), Bulgaria (900–1,200), Slovakia (with about 600–800 animals), Slovenia (500–700 animals), and Greece (with Karamanlidis et al. 2015 estimating >450 animals) in the south. In Asia, brown bears are found primarily throughout Russia, thence more spottily southwest to parts of the Middle East, including the Eastern Black Sea Region, Turkey which has 5,432 individuals of brown bear, to as far south as southwestern Iran, and to the southeast in Northeast China. Brown bears are also found in Western China, Kyrgyzstan, North Korea, Pakistan, Afghanistan, and India. A population of brown bears can be found on the Japanese island of Hokkaido, which holds the largest number of non-Russian brown bears in eastern Asia, with about 2,000–3,000 animals.
Conservation status. While the brown bear's range has shrunk and it has faced local extinctions, it remains listed as a least-concern species by the IUCN, with a total population of approximately 200,000. , the brown bear and the American black bear are the only bear species not classified as threatened by the IUCN. However, the California grizzly bear, Ungava brown bear, Atlas bear, and Mexican grizzly bear, as well as brown bear populations in the Pacific Northwest, were hunted to extinction in the 19th and early 20th centuries and many of the southern Asian subspecies are highly endangered. The Syrian brown bear ("U. a. syriacus") is very rare and it has been extirpated from more than half of its historic range. One of the smallest-bodied subspecies, the Himalayan brown bear ("U. a. isabellinus"), is critically endangered: it occupies only 2% of its former range and is threatened by uncontrolled poaching for its body parts. The Marsican brown bear in central Italy is believed to have a population of just 50 bears.
The smallest populations are most vulnerable to habitat loss and fragmentation, whereas the largest are primarily threatened by overhunting. The use of land for agriculture may negatively effect brown bears. Additionally, roads and railway tracks could pose a serious threat, as oncoming vehicles may collide with crossing animals. Poaching has been cited as another mortality factor. In one instance, a 3-year-long survey in the Russian Far East detected the illegal shipping of brown bear gallbladders to Southeast Asian countries. The purpose and motive behind the trade is unknown. An action plan in 2000 aimed to conserve brown bears in Europe by mitigating human–wildlife conflict, educating farm owners as to sustainable practices, and preserving and expanding remaining forests. Compensation was given to people who suffered losses of livestock, food supplies, or shelter. Growing bear populations were recorded in some countries, such as Sweden, where an increase of 1.5% per annum occurred between the 1940s and 1990s. Brown bears in Central Asia are primarily threatened by climate change. In response to this, conservationists plan on building wildlife corridors to promote easy access from one brown bear population to another. In Himalayan Nepal, farmers may kill brown bears in revenge for livestock predation.
Behavior and life history. A 2014 study revealed that brown bears peaked in activity around the morning and early evening hours. Although activity can happen day or night, bears that live in locations where they are apt to interact with humans are more likely to be fully nocturnal. In areas with little interaction, many adult bears are primarily crepuscular, while yearlings and newly independent bears appear to be most active throughout the day. From summer through autumn, a brown bear can double its weight from what it was in the spring, gaining up to of fat, on which it relies to make it through winter, when it becomes lethargic. Although they are not full hibernators and can be woken easily, both sexes prefer to den in a protected spot during the winter months. Hibernation dens may be located at any spot that provides cover from the elements and that can accommodate their bodies, such as a cave, crevice, cavernous tree roots, or hollow logs.
Communication. Several different facial expressions have been documented in brown bears. The "relaxed-face" is made during everyday activities, a face where the ears pointed to the sides and the mouth closed or slackly open. During social play, bears make "relaxed open-mouth face" in which the mouth is open, with a curled upper lip and hanging lower lip, and the ears alert and shifting. When looking at another animal at a distance, the bear makes an "alert face" as the ears are cocked and alert, the eyes wide open with the mouth is closed or only open slightly. The "tense closed mouth face" is made with the ears laid back and the mouth closed, and occurs when the bear feels threatened. When approached by another individual, the animal makes a "puckered-lip face" with a protruding upper lip and ears that go from cocked and alert when at a certain distance to laid back when closer or when retreating. The "jaw gape face" consists of an open mouth with visible lower canines and hanging lips while the "biting face" is similar to the "relaxed open-mouth face" except the ears are flattened and the eyes are wide enough to expose the sclera. Both the "jaw gape face" and the "biting face" are made when the bear is aggressive and can quickly switch between them.
Brown bears also produce various vocalizations. Huffing occurs when the animal is tense, while woofing is made when alarmed. Both sounds are produced by exhalations, though huffing is harsher and is made continuously (approximately twice per second). Growls and roars are made when aggressive. Growling is "harsh" and "guttural" and can range from a simple "grrr" to a rumble. A rumbling growl can escalate to a roar when the bear is charging. Roaring is described as "thunderous" and can travel . Mothers and cubs wanting physical contact will bawl, which is heard as "waugh!, waugh!". Home ranges. Brown bears usually inhabit vast home ranges; however, they are not highly territorial. Several adult bears roam freely over the same vicinity without contention, unless rights to a fertile female or food sources are being contested. Despite their lack of traditional territorial behavior, adult males seem to have a "personal zone" within which other bears are not tolerated if they are seen. Males always wander further than females, due to such behavior giving increasing access to both females and food sources. Females have the advantage of inhabiting smaller territories, which decreases the likelihood of encounters with male bears who may endanger their cubs.
In areas where food is abundant, such as coastal Alaska, home ranges for females and males are up to and , respectively. Similarly, in British Columbia, bears of the two sexes travel in relatively compact home ranges of . In Yellowstone National Park, home ranges for females are up to and up to for males. In Romania, the largest home range was recorded for adult males (). In the central Arctic of Canada, where food sources are quite scarce, home ranges range up to for females and for males. Reproduction. The mating season occurs from mid-May to early July, shifting to later in the year the farther north the bears are found. Brown bears are polygynandrous, remaining with the same mate for a couple of days to a couple of weeks and mating multiply during the mating season. Outside of this narrow time frame, adult male and female brown bears show no sexual interest in each other. Females mature sexually between the ages of four and eight. Males first mate about a year later, when they are large and strong enough to compete with other males for mating rights. Males will try to mate with as many females as they can; usually a successful male will mate with two females in a span of one to three weeks. Similarly, adult female brown bears can mate with up to four, sometimes even eight, males while in oestrus (heat), potentially mating with two in a single day. Females come into oestrus every three to four years, with an outside range of 2.4 to 5.7 years. The urine markings of a female in oestrus can attract several males via scent. Dominant males may try to sequester a female for her entire oestrus period of approximately two weeks, but usually are unable to retain her for the entire time. Copulation is prolonged and lasts for over 20 minutes.
Males take no part in raising cubs – parenting is left entirely to the females. Through the process of delayed implantation, a female's fertilized egg divides and floats freely in the uterus for six months. During winter dormancy, the fetus attaches to the uterine wall. The cubs are born eight weeks later, while the mother sleeps. If the mother does not gain enough weight to survive through the winter while gestating, the embryo does not implant and is reabsorbed into the body. Litters consist of as many as six cubs, though litters of one to three are more typical. The size of a litter depends on factors such as geographic location and food supply. At birth, cubs are blind, toothless and hairless and may weigh . There are records of females sometimes adopting stray cubs or even trading or kidnapping cubs when they emerge from hibernation (a larger female may claim cubs from a smaller one). Older and larger females within a population tend to give birth to larger litters. The cubs feed on their mother's milk until spring or early summer, depending on climate conditions. At this time, the cubs weigh and have developed enough to follow and forage for solid food with their mother over long distances.
The cubs are dependent on the mother and a close bond is formed. During the dependency stage, the cubs learn (rather than inherit as instincts from birth) survival techniques, such as which foods have the highest nutritional value and where to obtain them; how to hunt, fish, and defend themselves; and where to den. Increased brain size in large carnivores has been positively linked to whether a given species is solitary, as is the brown bear, or raises offspring communally. Thus, the relatively large, well-developed brain of a female brown bear is presumably key in teaching behavior. The cubs learn by following and imitating their mother's actions during the period they are with her. Cubs remain with their mother for an average of 2.5 years in North America, and gain independence from as early as 1.5 years of age to as late as 4.5 years. The stage at which independence is attained may generally be earlier in some parts of Eurasia, as the latest date which mother and cubs were together was 2.3 years. Most families separated in under two years in a study in Hokkaido, and in Sweden most yearlings were their own. Brown bears practice infanticide, as an adult male bear may kill the cubs of another. When an adult male brown bear kills a cub, it is usually because he is trying to bring the female into oestrus, as she will enter that state within two to four days after the death of her cubs. Cubs may flee up a tree when they see a strange male bear approaching. The mother often successfully defends them, even though the male may be twice as heavy as she. However, females have been known to die in such confrontations.
Dietary habits. The brown bear is one of the most omnivorous animals and has been recorded as consuming the greatest variety of foods of any bear. Despite their reputation, most brown bears are not highly carnivorous, as they derive up to 90% of their dietary food energy from vegetable matter. They often feed on a variety of plant life, including berries, grasses, flowers, acorns, and pine cones, as well as fungi such as mushrooms. Among all bears, brown bears are uniquely equipped to dig for tough foods such as roots, bulbs, and shoots. They use their long, strong claws to dig out earth to reach roots and their powerful jaws to bite through them. In spring, winter-provided carrion, grasses, shoots, sedges, moss, and forbs are the dietary mainstays for brown bears internationally. Fruits, including berries, become increasingly important during summer and early autumn. Roots and bulbs become critical in autumn for some inland bear populations if fruit crops are poor. They will also commonly consume animal matter, which in summer and autumn may regularly be in the form of insects, larvae, and grubs, including beehives. Bears in Yellowstone eat an enormous number of moths during the summer, sometimes as many as 40,000 army cutworm moths in a single day, and may derive up to half of their annual food energy from these insects. Brown bears living near coastal regions will regularly eat crabs and clams. In Alaska, bears along the beaches of estuaries regularly dig through the sand for clams. This species may eat birds and their eggs, including almost entirely ground- or rock-nesting species. The diet may be supplemented by rodents or similar small mammals, including marmots, ground squirrels, mice, rats, lemmings, and voles. With particular regularity, bears in Denali National Park will wait at burrows of Arctic ground squirrels, hoping to pick off a few of those rodents.
In the Kamchatka peninsula and several parts of coastal Alaska, brown bears feed mostly on spawning salmon, whose nutrition and abundance explain the enormous size of the bears in those areas. The fishing techniques of bears are well-documented. They often congregate around falls when the salmon are forced to breach the water, at which point the bears will try to catch the fish in mid-air (often with their mouths). They will also wade into shallow water, hoping to pin a slippery salmon with their claws. While they may eat almost all the parts of the fish, bears at the peak of salmon spawning, when there is usually a glut of fish to feed on, may eat only the most nutrious parts of the salmon (including the eggs and head) and then indifferently leave the rest of the carcass to scavengers, which can include red foxes, bald eagles, common ravens, and gulls. Despite their normally solitary habits, brown bears will gather closely in numbers at good spawning sites. The largest and most powerful males claim the most fruitful fishing spots and will sometimes fight over the rights to them.
Beyond the regular predation of salmon, most brown bears are not particularly active predators. While perhaps a majority of bears of the species will charge at large prey at one point in their lives, many predation attempts start with the bear clumsily and half-heartedly pursuing the prey and end with the prey escaping alive. On the other hand, some brown bears are quite self-assured predators who habitually pursue and catch large prey. Such bears are usually taught how to hunt by their mothers from an early age. Large mammals preyed on can include various ungulate species such as elk, moose, caribou, muskoxen, and wild boar. When brown bears attack these large animals, they usually target young or infirm ones, which are easier to catch. Typically when hunting (especially young prey), the bear pins its prey to the ground and then immediately tears at and eats it alive. It will also bite or swipe some prey to stun it enough to knock it over for consumption. In general, large mammalian prey is killed with raw strength and bears do not display the specialized killing methods of felids and canids. To pick out young or infirm individuals, bears will charge at herds so the more vulnerable, and thus slower-moving, individuals will become apparent. Brown bears may ambush young animals by finding them via scent.
When emerging from hibernation, brown bears, whose broad paws allow them to walk over most ice and snow, may pursue large prey such as moose, whose hooves cannot support them on encrusted snow. Similarly, predatory attacks on large prey sometimes occur at riverbeds, when it is more difficult for the prey specimen to run away due to muddy or slippery soil. On rare occasions, while confronting fully-grown, dangerous prey, bears kill them by hitting with their powerful forearms, which can break the necks and backs of large creatures such as adult moose and adult bison. They feed on carrion, and use their size to intimidate other predators – such as wolves, cougars, tigers, and American black bears – away from their kills. Carrion is especially important in the early spring (when the bears are emerging from hibernation), much of it comprising winter-killed big game. Cannibalism is not unheard of, though predation is not normally believed to be the primary motivation when brown bears attack each other. When forced to live in close proximity with humans and their domesticated animals, bears may potentially predate any type of domestic animal. Among these, domestic cattle are sometimes exploited as prey. Cattle are bitten on the neck, back, or head, and then the abdominal cavity is opened for eating. Plants and fruit farmed by humans are readily consumed as well, including corn, wheat, sorghum, melons, and any form of berries. They may feed on domestic bee yards, readily consuming both honey and the brood (grubs and pupae) of the honey bee colony. Human foods and trash are eaten when possible. When an open garbage dump was kept in Yellowstone, brown bears were one of the most voracious and regular scavengers. The dump was closed after both brown and American black bears came to associate humans with food and lost their natural fear of them.
Relations with other predators. Adult bears are generally immune to predatory attacks except from large Siberian (Amur) tigers and other bears. Following a decrease of ungulate populations from 1944 to 1959, 32 cases of Siberian tigers attacking both Ussuri brown bears ("Ursus arctos lasiotus") and Ussuri black bears ("U. thibetanus ussuricus") were recorded in the Russian Far East, and bear hairs were found in several tiger scat samples. Tigers attack black bears less often than brown bears, since the brown bears live in more open habitats and are not able to climb trees. In the same time period, four cases of brown bears killing female tigers and young cubs were reported, both in disputes over prey and in self-defense. In rare cases, when Amur tigers prey on brown bears, they usually target young and sub-adult bears, besides small female adults taken outside their dens, generally when lethargic from hibernation. Predation by tigers on denned brown bears was not detected during a study carried out between 1993 and 2002. Ussuri brown bears, along with the smaller black bears constitute 2.1% of the Siberian tiger's annual diet, of which 1.4% are brown bears.
Brown bears regularly intimidate wolves to drive them away from their kills. In Yellowstone National Park, bears pirate wolf kills so often, Yellowstone's Wolf Project director Doug Smith wrote, "It's not a matter of if the bears will come calling after a kill, but when." Despite the animosity between the two species, most confrontations at kill sites or large carcasses end without bloodshed on either side. Though conflict over carcasses is common, on rare occasions the two predators tolerate each other at the same kill. To date, there is a single recorded case of fully-grown wolves being killed by a grizzly bear. Given the opportunity, however, both species will prey on the other's cubs. In some areas, grizzly bears regularly displace cougars from their kills. Cougars kill small bear cubs on rare occasions, but there was only one report of a bear killing a cougar, of unknown age and condition, between 1993 and 1996.
Longevity and mortality. The brown bear has a naturally long life. Wild females have been observed reproducing at 28 years, which is the oldest known age for reproduction of any ursid in the wild. The peak reproductive age for females ranges from four to 20 years old. The lifespan of both sexes within minimally hunted populations is estimated at an average of 25 years. The oldest recorded wild individual was nearly 37 years old. In captivity, the oldest recorded female was around 40 years old, while males have been known to live up to 47 years. While male bears potentially live longer in captivity, female grizzly bears have a greater annual survival rate than males within wild populations, per a study done in the Greater Yellowstone Ecosystem. Annual mortality for bears of any age is estimated at 10% in most protected areas. Around 13% to 44% of cubs die within their first year. Beyond predation by large predators – including wolves, Siberian tigers, and other brown bears – starvation and accidents also claim the lives of cubs. Studies have indicated that the most prevalent cause of mortality for first-year cubs is malnutrition.
Brown bears are susceptible to parasites such as flukes, ticks, tapeworms, roundworms, and biting lice. It is thought that brown bears may catch canine distemper virus (CDV) from other caniforms such as stray dogs and wolves. A captive individual allegedly succumbed to Aujeszky's disease. Hibernation physiology. A study conducted by the Brown Bear Research Project did a proteomic analysis of the brown bear's blood, organs, and tissues to pinpoint proteins and peptides that either increased or decreased in expression in the winter and summer months. One major finding was that the presence of the plasma protein sex hormone-binding globulin (SHBG) increased by 45 times during the brown bear's hibernation period. Although scientists do not yet understand the role of SHBG in maintaining the brown bear's health, some believe these findings could potentially help in understanding and preventing human diseases that come from a sedentary lifestyle. Relations with humans. Attacks on humans. Brown bears usually avoid areas where extensive development or urbanization has occurred. They usually avoid people and rarely attack on sight. They are, however, unpredictable in temperament, and may attack if threatened or surprised. Mothers defending cubs are the most prone to attacking, being responsible for 70% of brown bear-caused human fatalities in North America. Attacks tend to result in serious injury and, in some cases, death. Due to the bears' enormous physical strength, a single bite or swipe can be deadly. Violent encounters with brown bears usually last a few minutes, though they can be prolonged if the victims fight back.
A study conducted in 2019 found that 664 bear attacks were reported during a 15-year period (20002015) throughout North America and Eurasia. There were 568 injuries and 95 fatalities. Around 10 people a year are killed by brown bears in Russia, more than all the other parts of the brown bear's range combined. In Japan, a large brown bear nicknamed "Kesagake" ("kesa-style slasher") caused the worst brown bear attack in Japanese history in Tomamae, Hokkaido, during numerous encounters during December 1915. It killed seven people and wounded three others before being gunned down during a large-scale beast-hunt. A study by U.S. and Canadian researchers has found bear spray to be more effective at stopping aggressive bear behavior than guns, working in 92% of studied incidents, versus 67% for guns. Bear hunting. Humans have been recorded hunting brown bears for over 10,300–9,300 years. Bears were hunted throughout their range in Europe, Asia and North America by both the Native Americans and Europeans. The former usually killed bears for survival needs, while the latter for sports or population control. In Europe, between the 17th and 18th centuries, humans sought to control brown bear numbers by awarding those who managed to kill one. This bounty scheme pushed the brown bear population to the brink of extinction before comprehensive protection was offered in the 1900s. Despite this, a 2018 study found hunting to be one of the contributing factors to the drop in brown bear numbers in northern Europe.
The earliest known case of a European killing a grizzly bear dates back to 1691. Their arrival in western United States led to the extirpation of local brown bear populations in the 19th and early 20th centuries. During the early years of European settlement in North America, bears were usually killed with a spear or lasso rope. The introduction of rifles in the mid-19th century largely facilitated bear hunts, which allowed for an increasing trend. Bears were also pitted into fights against male cattle, often ending with either animal grievously injured or dead. The last two decades of the 19th century saw an increase in bounties. Conflicts with farmers also contributed to its rapid decline. It wasn't until the 1920s that grizzly bears received some type of protection from the US government. Today, brown bears are legally hunted in some American states, such as Alaska. However, a hunting license is required and killings of nurturing females and cubs will result in a prison sentence. Brown bear meat is sometimes consumed and used in recipes such as dumplings, hams and stews. The Indigenous people of James Bay (Eastern) Cree use their flesh in traditional dishes. In Asia and Romania, the paws are consumed as exotic delectables; they have been a prevalent component of traditional Chinese food since 500 BC. The total weight of commercially sold brown bear meat is estimated at 17 tons annually.
In captivity. Bears have been recorded in captivity as early as 1,500 BC. As of 2017, there are more than 700 brown bears in zoos and wildlife parks worldwide. Captive bears are largely lethargic and spend a considerable amount of time doing nothing. When active, captive bears may engage in repetitive back and forth motion, known widely as pacing. This behavior is most prevalent in bears kept in small, cramped cages often with no natural setting. Pacing is a way of coping with stress that comes with being trapped in unnaturally small spaces. These stereotyped behaviors have decreased due to better and larger enclosures being built, and more sustainable management from zoo staff. Starting from infancy, brown bears may also be exploited as dancing bears. Cubs, for example, are positioned on hot metal plates, causing them to "dance" to the sound of violin music running in the background. The process is repeated, resulting in bears being trained to "dance" when a violin is played. Similarly, brown bears are displayed in tiny enclosures near a restaurant, mainly for the purpose of luring customers. Privately owned bears are also placed in insufficient environments and often suffer from malnutrition and obesity.
Brown bears have been popular attractions at circuses and other acts since ancient times. Due to their large size and imposing demeanor, the Romans used brown bears in the execution of criminals, and pitted bears in fights with other animals. Gladiators would also fight bears, in what was essentially a fight to the death. Such events occurred in amphitheaters housing thousands of spectators. In later times, street performances became popular in the Middle Ages; acts included "dancing" and "sleeping on command". These performances became increasingly widespread, and from the 1700s to 1800s, traveling circuses would perform in the streets of many European and Asian countries. Such circuses made use of bears that wore special clothing, and were usually run by musicians. A short while later, modern circuses began utilizing bears around the second half of the 18th century. Brown bears were said to be the easiest bear species to train due to their intelligence, unique personalities, and exceptional stability. According to a 2009 analysis, the brown bear was the second most exploited circus animal after the tiger.
Culture. Bears have been popular subjects in art, literature, folklore, and mythology. The image of the mother bear was prevalent throughout societies in North America and Eurasia, based on the female's devotion and protection of her cubs. The earliest cave paintings of bears occurred in the Paleolithic, with over 100 recorded paintings. Brown bears often figure in the literature of Europe and North America as "cute and cuddly", in particular that which is written for children. "The Brown Bear of Norway" is a Scottish fairy tale telling of the adventures of a girl who married a prince magically turned into a bear and who managed to get him back into a human form by the force of her love after many trials and tribulations. With "Goldilocks and the Three Bears", a story from England, the Three Bears are usually depicted as brown bears. In German-speaking countries, children are often told the fairytale of "Snow White and Rose Red"; the handsome prince in this tale has been transfigured into a brown bear. In the United States, parents often read their preschool age children the book "Brown Bear, Brown Bear, What Do You See?" to teach them their colors and how they are associated with different animals. Smokey Bear, the famous mascot of U.S. Forest Service, has since the 1940s been used to educate people on the dangers of human-caused wildfire.
Brown bears have been extensively featured in the culture of Native Americans, and are considered sacred. To stop a bear's spirit from escaping after it was killed, the Denaa people severed all 4 of its paws. They delayed consuming brown-bear flesh, owing to the belief that the bear's spirit was overwhelming in fresh kills. In addition, community members that wore bear claw necklaces were highly respected, as wearing one was seen as a sign of bravery and honor. The clattering caused by repeatedly shaking these necklaces were believed to bring forth therapeutic powers. In Haida culture, one legend has it that a marriage between a woman and a grizzly bear commenced the lineage of the native people. This is thought to have allowed the Haida to thrive in bear country. There is evidence of prehistoric bear worship, though this is disputed by archaeologists. It is possible that bear worship existed in early Chinese and Ainu cultures. The Romans built small carved figures of bears that were used during the burials of infants. In Ancient Greek mythology, bears were considered similar to humans, mainly due to their ability to stand upright. In many western stories and older fables the portrayed attributes of bears are sluggishness, foolishness, and gullibility, which contradicts the actual behavior of the species. For example, bears have been reported tricking hunters by backtracking in the snow.