Ursus arctos

Brown Bear


  • Kingdom: Animalia
  • Phylum: Chordata
  • Class: Mammalia
  • Order: Carnivora
  • Family: Ursidae
  • Genus: Ursus
  • Species: arctos

Scientific Name: Ursus arctos

IUCN Red List Status and Population

Least Concern (McLellan et al. 2017)

Population Trend: Stable <200,000 individuals

Asia and Russia-100,000, US (Alaska)- 33,000, Canada-25,000, Europe (excluding Russia)-15,400 (McLellan et al. 2017). Northern populations are relatively abundant, with southern populations highly fragmented containing very small subpopulations. Yellowstone National Park contains approximately 700 brown bears, the Cabinet Mountains of Montana with 25 individuals, and less than 10 bears in British Columbia (McLellan et al. 2017). In the lower 48 states, there are approximately 1,800 brown bears in five small isolated subpopulations (“Basic Facts about Grizzly Bears”).

22 European Countries with 10 subpopulations, as well as small subpopulations scattered throughout Asia (McLellan et al. 2017).

For more information on population distribution: visit iucnredlist.org

Species Information

Weight: average ~ 700 pounds, range from 400-1200 pounds (“Brown Bear” 2017), (“Brown Bear” Bearlife.org).

Males: 300-850 pounds, Females 200-450 pounds (“Basic Facts about Grizzly Bears”).

Length: 5-8 feet

Height: 3.5 feet

Lifespan: 25 years in the wild.

About: A group of brown bears is called a sloth or a sleuth, although they are typically solitary animals, they can be seen peacefully together when food is abundant. Although territorial, their home ranges can overlap (“Brown Bear Fact Sheet” 2012). Bears communicate with sounds, smell, and movement. National Geographic notes that they mark their territory by rubbing their bodies against trees, stomping urine into the ground, as well as scraping trees and defecating. They have extremely wide ranges of territory and can roam up to a thousand square miles in the search for food (“Brown Bear” 2017).

A sloth of brown bears occurs in prime salmon spawning areas with an abundance of food in the summer. They have an extreme sense of smell, being 2,100 times greater than a human. They use it to forage for food and to find potential mates within their home range, with males roaming much further distances than females. The largest of the brown bears are found in coastal British Columbia, Alaska, and the Kodiak islands, these bears are called the Kodiak Bear (Ursus arctos middendorffi) (“Brown Bear” 2017). Brown bears are sexually dimorphic, with males weighing close to two times that of a female.

Despite their large size, brown bears can run up to 30 miles an hour and are very dangerous to humans, especially when snuck up on or a mother with cubs. They also do not have to be brown in color to be called a brown bear, with colors ranging from dark brown to cream. They are distinguished from a black bear by their larger size and a distinct hump between their shoulders. This bulky muscle mass aids in powerful forearms for digging. Their claws are also longer and blunter for digging and have a stronger build than black bears. Their claws can be the length of an average human finger. Brown bears are excellent swimmers, but only climb trees when they are cubs (“Brown Bear Fact Sheet” 2012).

Diet: Brown bears can eat 90 pounds of food per day during the fall, packing on as much weight as possible for their winter torpor, weighing double what they will once they awake in the Spring. They can lose 150 pounds over the winter (“Brown Bear” 2017).

Brown bears exploit a wide variety of diet and is dependent on available food sources. Brown bears are omnivorous, their diet is based on both plant materials and protein. Being an apex predator, they have no natural predators and are at the top of the food chain (“Brown Bear Fact Sheet” 2012). More carnivorous bears are found where ungulate breeding, as well as salmon, are abundant, mainly in North America (McLellan et al. 2017). The density of brown bears depends on habitat and prey abundance. High prey densities also correspond with high reproductive rates of brown bears.

In both Europe and Asia, brown bears tend to forage more on a variety of plant materials such as grasses, roots, berries, fruits, and protein sources if available (McLellan 2017). The lowest density of brown bears is where food is scarce, such as in the dry desert areas, or areas where human population growth has caused low habitat availability (McLellan et al. 2017). Although classified under Carnivora, brown bears are omnivores and consume much more plant materials than protein in most areas.

Reproduction: Brown bears breed between April to July, with delayed implantation until Autumn. They are one of the slowest reproducing land mammals (“Basic Facts about Grizzly Bears”). Cubs are born in litters from 1-3, and are born in January or February when the mother is undergoing winter torpor or a deep sleep (McLellan et al. 2017). Cubs are born completely furless and blind, finding their mother’s nipple to attach to until Spring (“Brown Bear”, Bearlife.org).

Mothers (sows) become sexually mature between 5-8 years of age and reproduce every 3-4 years, although reproduction varies depending on the region (McLellan et al. 2017). Sows teach their cubs survival skills such as foraging for food and exploring their territory.


Not True Hibernators: During this winter sleep or period of torpor, brown bears do not wake up to defecate, drink water, or eat food. This is an important distinction between true hibernators, who wake up about once a week to excrete waste, as well as refuel with food they have cached for the winter months. These animals include rodent species, frogs, snakes, some marsupial species, as true hibernators. Their body temperatures and heart rate decrease exponentially, while a bear’s body temperature and heart rate only decrease slightly. True hibernators are also not easily woken up from their hibernating, while bears are able to wake up immediately while disturbed to defend themselves and their dens. Brown bears dig large dens for their winter sleeping period on the side of hills or in a suitable area.

In areas where food is abundant and the weather is tolerable during winter months, bears will not undergo torpor and will remain awake to feed. Winter sleep occurs approximately from October/December to March/May depending on the harshness of the winter, according to the World Wildlife Fund (“Brown Bear”). Bears will continue to reuse the same den areas if available the next year.


Habitat Types: Variety of habitats, from dry Asian steppes to Arctic shrub lands to temperate forests, from sea level to 5,000m (McLellan et al. 2017). They inhabit more variable habitats than any other bear species.

Historic Home Ranges: Western North America, Northern Mexico, Ungaca Peninsula, Europe, Asia, Middle East, and North Africa (McLellan et al. 2017).

Prolonged exploitation in Europe resulted in extirpation of brown bears from many countries. In North Africa, it was thought the brown bear was extirpated in the 1500s in Sinai of Egypt, and the 1800s in Algeria and Morocco (McLellan et al. 2017). Brown bears (known as grizzly bears in these regions) in Mexico were purposely extirpated in the 1960s, as well as in the southwestern United States and Canadian prairies. They were thought to not exist within the Middle East, however recent sightings have found bears in Western Syria, near the Lebanon border (McLellan et al. 2017). In the early 1990s, it was estimated by the WWF that the United States had 100,000 brown bears (“Facts”).

Current Home Ranges: Brown bears are the most widely distributed bear throughout the world, occupying 5 million square kilometers of the northwest portion of North America, 1.2 million square kilometers of Europe (excluding Russia), as well as much of Northern Asia (McLellan et al. 2017). The largest number of brown bears are found in Russia, the U.S. (Alaska), and Canada. Other populations are small and isolated in other parts of the world. In Iraq and Nepal, there are extremely small existing populations, and few individuals have been seen roaming Switzerland to Northern Italy (McLellan et al. 2017). Their sightings have not been frequent enough to consider a true home range in these countries. Although widely distributed, they still only inhabit 2% of their natural home range due to human development (“Brown Bear” WWF).

Two subspecies are found in North America: Ursus arctos middendorffi the Kodiak bear, and Ursus arctos horribilis the Grizzly bear (“Brown Bear Fact Sheet” 2012).

Image: “Basic Facts about Grizzly Bears”, Defenders of Wildlife


Brown bear populations are frequently hunted in areas that have large populations, for either sport or population control. The IUCN Red List of Threatened Species states that sometimes the killing rates are unsustainable, although exploitation rates are difficult to monitor due to research expenses within large contiguous brown bear ranges (McLellan et al. 2017). Many countries do not have the adequate management or resources in order to properly sustain brown bear populations.

Illegal killing and trade of brown bears are predicted to exceed the number of legal killings, according to the IUCN (McLellan et al. 2017). This occurs mainly in Far East Russia and China, where the bears are poached for the illegal commercial trade for their gall bladders and paws (McLellan et al. 2017). There is no evidence that brown bear body parts and gallbladder provide any medicinal or medical value.

In the United States, brown bear populations are reduced in Alaska to encourage greater populations of Moose and Caribou for the benefit of hunters (McLellan et al. 2017).

Small isolated populations are threatened by their low numbers as well as continuous contact with humans (McLellan et al. 2017). Habitat fragmentation has caused the isolation of these populations due to human development, and leave wildlife vulnerable to inbreeding and prevent them from roaming to find food resources. Bears are extremely food motivated and tend to cause human-wildlife conflict due to their aggressive nature and willingness to inhabit developed areas for food sources.

Acting as “mortality sinks,” many of these bears are killed due to their threat to human populations, states the IUCN (McLellan et al. 2017). Removing bears from small populations has an extreme effect, decreasing diversity and hindering population growth. Human-caused mortality is the number one cause of brown bear population decline (“Brown Bear Fact Sheet” 2012).

Bear habitats are under threat due to population growth and human development for highways, agriculture, wind power, and urban development. This causes fragmented populations and habitats, seriously threatening brown bears and their native homes (McLellan et al. 2017).

Four out of ten brown bear subpopulations in Europe are critically endangered but have secured short-term survival due to public interest and awareness (McLellan et al. 2017). To guarantee long-term survival, the IUCN suggests that present and future threats to brown bear populations must be kept in check (McLellan et al. 2017). Key threats include habitat loss, disturbance, low brown bear acceptance, poor management, and persecution – all are expected to increase in the future (McLellan et al. 2017).

Why Brown Bears Matter

Brown bears are majestic symbols of wildlife, and their beauty is represented in cultures all over the world. They live in a variety of habitat types acting as an umbrella species. Being an umbrella species means that by protecting brown bears we are protecting the entire ecosystem surrounding them. They also help their ecosystem by dispersing seeds through their scat, and regulate ungulate populations, according to Defenders of Wildlife (“Facts about Grizzly Bears”).

Brown bears depend on large natural areas for survival, and are a high priority in management due to their indication of ecosystem health, as indicated by the World Wildlife Fund (“Facts”). Managing brown bears helps to protect the natural world, and ensures the survival of many other species of wildlife.

Conservation Actions

Conservation varies depending on the region or nation in which brown bears reside. Many areas with large populations manage the species as a legally hunted game animal; including Russia, Japan, Canada, Alaska, Eastern Europe, and Northern Europe (McLellan et al. 2017). Hunts are typically regulated to ensure sustainable harvest, including a season length and a limited number of hunts per year.

Brown bears are listed under  Convention on International Trade in Endangered Species (CITES) Appendix II for populations in Bhutan, China, and Mongolia. Species are listed under Appendix I under the subspecies Ursus arctos isabellinus in North India, Pakistan, Afghanistan, Gobi Desert, and Kazakhstan (McLellan et al. 2017).

The European Union (EU) restricts international trade in bear products from certain countries, and the bear populations are protected by the Habitat Directive, which limits the number of brown bears that can legally be hunted, as well as helps clarify a management plan for the species (McLellan et al. 2017). There is a focus on minimizing human-bear conflict by working with the government to protect wild bear effectively with management tactics in place through the WWF (“Facts”).

The United States has increased brown bear protection under the Endangered Species Act 1973.  Reintroduction and connectivity management have benefitted populations within the US, southern Canada, and western Europe (McLellan et al. 2017).

The World Wildlife Fund (WWF) in the United States and Canada has established a conservation effort to protect Rocky Mountain grizzlies, cougars, and wolves by protecting ecosystem hotspots encompassing vast biodiversity (“Creative Partnership Aims to protect Rocky Mountain Grizzlies, Wolves and Cougars” 2004). WWF also works to conserve bear populations and vital habitats by forging partnerships with businesses to ensure adequate management is in place (“Facts”).

Brown bears are referred to as “grizzly” bears due to the white/gray tips on their coat. Their scientific subspecies name, horribilis, was influenced by an interaction that Lewis and Clark have with a grizzly bear (“Brown Bear Fact Sheet” 2012).

Polar bears are thought to have evolved from brown bears 150,000 years ago (“Brown Bear Fact Sheet” 2012).



  1. “Basic Facts About Grizzly Bears”. Defenders of Wildlife n.d. https://defenders.org/grizzly-bear/basic-facts
  2. “Brown Bear”. National Geographic Society 2017. https://www.nationalgeographic.com/animals/mammals/b/brown-bear/
  3. “Brown Bear”. Bearlife.org. n.d. http://www.bearlife.org/brown-bear.html
  4. “Brown Bear”. World Wildlife Fund for Nature: WWF. N.d http://wwf.panda.org/about_our_earth/species/profiles/mammals/brown_bear2/
  5. “Brown Bear Fact Sheet”. Nature; PBS Thirteen 9 July 2012. http://www.pbs.org/wnet/nature/bears-of-the-last-frontier-brown-bear-fact-sheet/6522/
  6. “Creative Partnership Aims to Protect Rocky Mountain Grizzlies, Wolves, and Cougars”. World Wildlife Fund (WWF) 22 July 2004. http://www.wwf.ca/newsroom/?1237
  7. Derych, John. “Brown/ Grizzly Bear Facts” 2001. North American Bear Centerhttps://www.bear.org/website/bear-pages/brown-or-grizzly-bear/68-brown-grizzly-bear-facts.html
  8. “Facts”. World Wildlife Fund 2017. https://www.worldwildlife.org/species/brown-bear
  9. McLellan, B.N., Proctor, M.F., Huber, D. & Michel, S. 2017. “Ursus arctos”. (amended version published in 2017) The IUCN Red List of Threatened Species 2017: e.T41688A121229971. http://dx.doi.org/10.2305/IUCN.UK.2017-3.RLTS.T41688A121229971.en.