Brown bear
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. The brown bear is thought to have evolved from the Etruscan bear 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. 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 they may have contributed to the extinction of cave bears. 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 between 92,000 and 83,000 BP upon the opening of the ice-free corridor. After a local extinction in Beringia around 33,000 BP, two new but closely related lineages repopulated Alaska and northern Canada from Eurasia after the Last Glacial Maximum.
Brown bears generally weigh between 140 and 635 kilograms, with males outweighing females. They have a head-and-body length of 1.5 to 2.8 meters and a shoulder height of 0.8 to 1.5 meters. The tail is relatively short, ranging from 6 to 22 centimeters in length. The smallest brown bears can weigh as little as 100 kilograms, roughly matching the body mass of males of the sun bear. Brown bears of the interior are generally smaller, being around the same weight as an average lion at an average of 180 kilograms in males and 120 kilograms in females. Adults of coastal populations weigh about twice as much. Brown bears have large, curved claws, with the front ones being larger than the back. They may reach 10 centimeters long and measure 15 centimeters along the curve. Compared with the American black bear, the brown bear has longer and stronger claws with a blunt curve. The species has large paws; the rear feet measure 30 to 40 centimeters 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. Adult brown bears have massive, heavily built, concave skulls, which are large in proportion to the body. Skull lengths of Russian brown bears tend to be 30 to 36 centimeters for males and 27 to 32 centimeters for females. Brown bears have strong jaws: the incisors and canine teeth are large, with the lower canines being strongly curved.
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 Europe, in 2010, there were 14,000 brown bears in ten fragmented populations, from Spain in the west to Russia in the east. There are an estimated 20 to 25 animals in the Pyrenees in 2010, in a range shared between Spain, France, and Andorra. Some 210 animals exist in Asturias, Cantabria, Galicia, and León in the Picos de Europa and adjacent areas in 2013. Romania holds 5,000 to 6,000 bears, Bulgaria has 900 to 1,200, Slovakia contains about 600 to 800 animals, Slovenia has 500 to 700 animals, and Greece has around 900 animals. 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 of Turkey which has 5,432 brown bears. 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 to 3,000 animals. The Marsican brown bear in central Italy is believed to have a population of just 50 bears. One of the smallest-bodied subspecies, the Himalayan brown bear, occupies only 2% of its former range.
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. 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. In Alaska, bears along the beaches of estuaries regularly dig through the sand for clams. In the Kamchatka peninsula and several parts of coastal Alaska, brown bears feed mostly on spawning salmon. 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. While they may eat almost all the parts of the fish, bears at the peak of salmon spawning may eat only the most nutrious parts of the salmon and then indifferently leave the rest of the carcass to scavengers. 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. Brown bears may also kill Asian black bears, though the latter species probably largely avoids conflicts with the brown bear.
The mating season occurs from mid-May to early July, shifting to later in the year the farther north the bears are found. 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. 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. Litters consist of as many as six cubs, though litters of one to three are more typical. At birth, cubs are blind, toothless and hairless and may weigh 300 to 450 grams. 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. Wild females have been observed reproducing at 28 years, which is the oldest known age for reproduction of any ursid in the wild. 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 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. However, the California grizzly bear, Ungava brown bear, Atlas bear, and Mexican grizzly bear were hunted to extinction in the 19th and early 20th centuries. One of the smallest-bodied subspecies, the Himalayan brown bear, 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. 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. 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. 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. A study conducted in 2019 found that 664 bear attacks were reported during a 15-year period from 2000 to 2015 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.
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. Brown bears have been popular attractions at circuses and other acts since ancient times. 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. 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. According to a 2009 analysis, the brown bear was the second most exploited circus animal after the tiger. The earliest cave paintings of bears occurred in the Paleolithic, with over 100 recorded paintings. 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. 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. The Russian bear is a common national personification for Russia, despite the country having no officially-designated national animal. The brown bear is Finland's national animal. The grizzly bear is the state animal of Montana. The California golden bear is the state animal of California, despite being extinct.
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Common questions
When did Carl Linnaeus scientifically describe the brown bear species?
Carl Linnaeus scientifically described the brown bear under the name Ursus arctos in the 1758 edition of Systema Naturae. This classification established the scientific foundation for all subsequent taxonomic studies of the species.
How many subspecies of brown bear have been proposed by authorities?
As many as 90 subspecies have been proposed, though few authorities list the same set of subspecies. A 2008 DNA analysis identified as few as five main clades while a 2017 phylogenetic study revealed nine clades including one representing polar bears.
What is the total population count of brown bears remaining in the world today?
There are approximately 200,000 brown bears left in the world with the largest populations located in Russia and North America. The species remains listed as a least-concern status by the IUCN despite facing local extinctions in certain regions.
Where do brown bears first migrate to during the Pleistocene period?
Brown bears first emigrated to North America from Eurasia via Beringia during the Illinoian Glaciation. They entered Europe 250,000 years ago and North Africa shortly after entering the continent.
What percentage of dietary food energy do most brown bears derive from vegetable matter?
Most brown bears derive up to 90% of their dietary food energy from vegetable matter rather than meat. They often feed on berries grasses flowers acorns pine cones and fungi such as mushrooms throughout their habitat.