The brown bear (Ursus arctos) is the most widely distributed bear on Earth, ranging across the forests, tundra, and mountains of the northern hemisphere. The grizzly bear of North America and the great brown bears of Eurasia all belong to this single species. Few large carnivores carry such cultural weight, and few illustrate so clearly the tension between a globally secure species and the fragile, isolated populations living at its southern edges.
Biology and Identification
The brown bear is a large-bodied omnivore distinguished by a prominent shoulder hump of muscle, a concave or "dished" facial profile, and long, curved foreclaws adapted for digging. Size varies enormously across the range: interior males commonly weigh around 200 kg while females average roughly 135 kg, but coastal populations with access to salmon grow substantially larger [Bear Biology 2024]. Coat color spans blond, cinnamon, and dark brown, and the silver-tipped guard hairs of many North American animals give the "grizzly" its name.
Brown bears are opportunistic feeders. Their diet shifts seasonally between roots, grasses, berries, nuts, insects, ungulate prey, and, where available, spawning salmon [Bear Biology 2024]. They enter a period of winter dormancy in dens, during which females give birth to small, altricial cubs. The species is long-lived, with wild individuals occasionally reaching their mid-thirties [Bear Biology 2024].
Habitat and Range
Ursus arctos occupies an exceptionally broad set of habitats, from Arctic tundra and boreal forest to temperate woodland, alpine meadow, and semi-arid steppe across North America, Europe, and Asia [McLellan et al. 2017]. In North America the species ranges over roughly five million square kilometers of the northwest, while the European range covers a far smaller area fragmented into many separate units [Bear Biology 2024]. The IUCN assessment recognizes 44 identified subpopulations worldwide, most concentrated in the southern portions of the species' circumpolar distribution [McLellan et al. 2017].
Brown bears are wide-ranging animals that depend on large, connected landscapes and the ability to move between seasonal food sources. Habitat fragmentation that severs these connections is among the most serious pressures the species faces [Chapron et al. 2014].
In accordance with NRWL sensitive-species policy, specific site locations, corridor routes, and seasonal movement details are not disclosed in this article.
Conservation Status
Globally, the brown bear is assessed by the IUCN Red List as Least Concern, under assessment ID e.T41688A121229971, published in 2017 [McLellan et al. 2017]. The global population is estimated at roughly 110,000 mature individuals and the overall population trend is considered stable [McLellan et al. 2017]. Europe alone holds on the order of 17,000 brown bears, making the species the continent's most numerous large carnivore [Chapron et al. 2014].
The brown bear is listed on the Appendices of CITES: populations of Bhutan, China, Mexico, and Mongolia are on Appendix I, while all other populations are on Appendix II [CITES 2024].
This globally secure status masks sharp regional contrasts. In the contiguous United States the grizzly bear (Ursus arctos horribilis) is protected as a threatened species under the U.S. Endangered Species Act, a listing first established in 1975; about 2,200 grizzlies remain across the lower 48 states, down from an estimated 50,000 before 1800 [USFWS 2025]. The Greater Yellowstone Ecosystem population, a recovery success, was estimated at roughly 1,030 bears in its core monitoring area in recent counts [IGBST 2024]. In Europe, several relict populations remain small and at high risk of local loss; the Cantabrian population of northwestern Spain had fallen below 100 animals in the early 1990s before beginning a genetic and demographic recovery [González et al. 2016].
Threats
Human-caused mortality is the leading driver of brown bear deaths, including conflict killings, poaching, and vehicle collisions, particularly where bears overlap with people and livestock [Bear Biology 2024]. Because bears reproduce slowly, even modest increases in adult mortality can push small populations toward decline.
Habitat loss and fragmentation isolate populations and cut off the movement corridors that bears need to find food and mates, leaving small units genetically and demographically exposed [Chapron et al. 2014].
Small-population effects compound these pressures. Isolated relict populations such as those in the Cantabrian Mountains and the Apennines suffer reduced genetic diversity and heightened risk of local extirpation even as the global species remains stable [González et al. 2016; McLellan et al. 2017].
What Is Being Done
Protective legislation and coexistence policy underpin the brown bear's broad recovery in Europe. Researchers attribute the persistence and expansion of large carnivores across human-dominated European landscapes to legal protection, supportive public opinion, and practical coexistence measures that allow bears to live outside strictly protected reserves [Chapron et al. 2014].
Reintroduction and reinforcement programs have rebuilt depleted populations. Under the EU-funded LIFE Ursus project, ten bears translocated from Slovenia to Italy's Adamello Brenta area between 1999 and 2002 had grown to roughly 47 animals by 2017 [Chapron et al. 2014].
Federal recovery under the U.S. Endangered Species Act, coordinated by the U.S. Fish and Wildlife Service and partner agencies, has driven the rebound of grizzly bears in the Greater Yellowstone and Northern Continental Divide ecosystems, supported by long-term monitoring from the Interagency Grizzly Bear Study Team [USFWS 2025; IGBST 2024].
Non-invasive genetic monitoring now allows managers to estimate population size and trend from hair and scat samples rather than invasive capture, improving the accuracy of counts that guide conservation decisions [Solberg et al. 2006].
How Readers Can Help
- Learn to recognize and respect bear country: store food securely, carry and know how to use bear spray, and keep a safe distance from wildlife.
- Support agencies and reputable organizations that fund habitat protection, corridor connectivity, and conflict-reduction programs.
- Reduce avoidable bear conflicts at home by securing garbage, livestock feed, and attractants in areas where bears occur.
- Follow and comment on public conservation processes, such as Endangered Species Act rulemakings, when you wish your views to be on the record.
- Share accurate, sourced information about brown bears rather than sensationalized claims.
References
[Bear Biology 2024] International Association for Bear Research and Management. Ursus arctos (Brown bear). The Eight Bear Species. https://www.bearbiology.org/the-eight-bear-species/ursus-arctos-brown-bear/
[Chapron et al. 2014] Chapron, G., Kaczensky, P., Linnell, J.D.C., et al. Recovery of large carnivores in Europe's modern human-dominated landscapes. Science, 346(6216), 1517–1519. https://doi.org/10.1126/science.1257553
[CITES 2024] Convention on International Trade in Endangered Species of Wild Fauna and Flora. Ursus arctos — Appendices. CITES Species Database. https://cites.org/eng/taxonomy/term/603
[González et al. 2016] González, E.G., Blanco, J.C., Ballesteros, F., Alcaraz, L., Palomero, G. & Doadrio, I. Genetic and demographic recovery of an isolated population of brown bear Ursus arctos L., 1758. PeerJ, 4, e1928. https://doi.org/10.7717/peerj.1928
[IGBST 2024] Interagency Grizzly Bear Study Team. Yellowstone Grizzly Bear Investigations 2024: Annual Report of the Interagency Grizzly Bear Study Team. U.S. Geological Survey. https://npshistory.com/publications/wildlife/igbst/ygbi-ann-rpt/2024.pdf
[McLellan et al. 2017] McLellan, B.N., Proctor, M.F., Huber, D. & Michel, S. Ursus arctos (amended version of 2017 assessment). The IUCN Red List of Threatened Species 2017: e.T41688A121229971. https://doi.org/10.2305/IUCN.UK.2017-3.RLTS.T41688A121229971.en
[Solberg et al. 2006] Solberg, K.H., Bellemain, E., Drageset, O.M., Taberlet, P. & Swenson, J.E. An evaluation of field and non-invasive genetic methods to estimate brown bear (Ursus arctos) population size. Biological Conservation, 128(2), 158–168. https://doi.org/10.1016/j.biocon.2005.09.025
[USFWS 2025] U.S. Fish & Wildlife Service. Endangered and Threatened Wildlife and Plants; Grizzly Bear Listing on the List of Endangered and Threatened Wildlife With a Revised Section 4(d) Rule. Federal Register, January 15, 2025. https://www.federalregister.gov/documents/2025/01/15/2025-00329/endangered-and-threatened-wildlife-and-plants-grizzly-bear-listing-on-the-list-of-endangered-and