Ursus arctos (Linnaeus, 1758)

Don E. Wilson & Russell A. Mittermeier, 2009, Ursidae, Handbook of the Mammals of the World – Volume 1 Carnivores, Barcelona: Lynx Edicions, pp. 448-497 : 495-496

7.

Brown Bear

Ursus arctos

French: Ours brun / German: Braunbär / Spanish: Oso pardo

Other common names: Grizzly Bear, Kodiak Bear

Taxonomy. Ursus arctos Linnaeus, 1758 ,

northern Sweden.

Genetic data corroborate the distinctiveness of some subspecies, such as isabellinus in Central Asia, but not others. Eight subspecies have been recognized in North America (seven of which are extant), but genetically these group into only three or four discrete clades, none of which match current subspecies designations. Conversely, whereas only one subspecies (artos) has been recognized for Europe, two geographically distinct lineages have been identified. California race californicus (Merriam, 1896) and north-western Africa race crowthert (Schinz, 1844) are extinct. Fourteen extant subspecies currently recognized.

Subspecies and Distribution.

U. a. arctos Linnaeus, 1758 — Europe and W Russia.

U. a. alascensis Merriam, 1896 — most of Alaska (excluding Alaska Peninsula, SE panhandle & Kodiak Island group).

U. a. beringianus Middendorff, 1853 — NE Russia (Kamchatka Peninsula & N Kuril Islands northward through the Koryak Autonomous District, and along W coast of the Sea of Okhotsk).

U. a. collaris Cuvier, 1824 — Russia (Siberia, from E of the Yenisey River to the Bering Sea, but excluding Kamchatka and more southern parts of the Russian Far East), N Mongolia.

U. a. dalli Merriam, 1896 — SE Alaska (N of Alexander Archipelago).

U. a. gyas Merriam, 1902 — Alaska peninsula.

U. a. horribilis Ord, 1815 —W Canada (Yukon, North-West Territories, British Columbia & Alberta), inland W USA (extirpated from S Wyoming to Mexico).

U. a. isabellinus Horsfield, 1826 — N India, Pakistan, Afghanistan, N to Kazakhstan and Mongolia (Gobi Desert).

U. a. lasiotus Gray, 1867 — Russia (Southern Kuril Islands, Sakhalin, Ussuri/ Amur river region of the Russian Far East), NE China, North Korea, and Japan (Hokkaido).

U. a. middendorffi Merriam, 1896 — Alaska (Kodiak Island & nearby islands).

U. a. pruinosus Blyth, 1853 — Tibetan Plateau, China, N Nepal.

U. a. sitkensis Merriam, 1896 — SE Alaska (Alexander Archipelago & adjacent coastal area).

U. a. stikeenensis Merriam, 1914 — W Canada (W British Columbia), and formerly W USA (W Washington and Oregon).

U. a. syriacus Hemprich & Ehrenberg, 1828 — Middle East, from Turkey to Iran (extirpated in Syria), Caucasus mountains of Russia, Georgia, Armenia and Azerbaijan.

Descriptive notes. Head-body 150-280 cm, shoulder height up to 150 cm, tail 6-21 cm. Weights vary regionally and seasonally, with food availability. Adult males are heavier (130-550 kg; rarely up to 725 kg) than adult females (80-250 kg, but occasionally up to 340 kg). Facial profile from forehead to nose is concave. Body profile includes a distinct muscular shoulder hump with long hairs. Coat color varies from uniform brown to mixed shades of brown, blond, and silver-tipped (grizzled), to partly gray or black, or fully black. The grizzled phase (Grizzly Bear) occurs in interior North America, whereas the black and partially black phases occur in eastern and central Asia. Color can lighten with bleaching from the sun. Prominent markings, from a white or creamcolored chest patch to a solid band that wrap across the chest and around the shoulders to the back, vary regionally and individually. Such markings are often present on cubs, but may be lost with age. Body hairs are sparser ventrally. Underfur is grown in fall, and molted in spring. Long, powerful, slightly curved front claws (4-10 cm) varying from dark brown to yellow to white, are characteristic. Foot pads are like that of the American Black Bear.

Habitat. Brown Bears occupy a wider range of habitats than any other bear, including both coniferous and deciduous forests, meadows, grasslands, Arctic shrublands and tundra, alpine tundra, semi-deserts and deserts. Their range overlaps that of both the American and Asiatic Black Bear, and also slightly that of the Polar Bear. They exist at elevations from sea level (temperate rainforests and Arctic tundra) to well above treeline (dry Asian steppes); highest elevation sightings (tracks in snow) have been at 5500 m (possibly 5800 m) in the Himalayas, and highest latitude sightings at 74° N ( Canada), well into Polar Bear range.

Food and Feeding. Food habits vary regionally from principally herbivorous to principally carnivorous, depending on habitat. Plant foods include grasses, sedges, horsetails, forbs, roots, berries, and nuts. Animal foods include insects, rodents, ungulates, and fish. Insects are a significant dietary component in broadleaved forests of Europe, rodents and ungulates are most important in Arctic and alpine areas and some Boreal forests, and fish are paramount along the Pacific Coast, from British Columbia to Alaska to Kamchatka ( Russia). Herbaceous vegetation tends to be the chief component of the spring diet. Later the bears switch to roots, berries, pine nuts, acorns, ants, bees, moths, ground squirrels, marmots, pikas, neonate ungulates, or spawning salmon, depending on availability. This species is morphologically and behaviorally well adapted to digging up insects and underground rodents,killing ungulates (including domestic species, like sheep and cattle), and catching salmon. In North America they rarely climb trees, whereas in Europe and parts of Asia they do so more regularly.

Activity patterns. Active diurnally in North America, except where human activity is high. Nocturnally active in most of Europe, possibly due to more frequent contact with humans, both historically and presently. Young bears in Europe are active uniformly through the day, but apparently learn to become more nocturnal through negative experiences with people. Total time active per day (40-80%) varies with local conditions (food, day length). The period of hibernation also varies regionally: at the northern extremes of their range they may hibernate for seven months (October-May); conversely, on Kodiak Island, Alaska, where winters are mild and some food may remain available, about one-quarter of the males do not den all winter, an unusual anomaly among Brown Bears. In Russia, following seasons with very poor food, large numbers of malnourished bears may wander about for much of the winter.

Movements, Home range and Social organization. Individual home range sizes vary by nearly four orders of magnitude (7-30,000 km?), related to food supply and bear density. Home ranges are largest in the barren-ground Arctic tundra, averaging 8000 km? for males. Rangesizes are smaller in boreal or montane forests, where large mammals are a main dietary component, and smaller yet in deciduous or mixed forests with hard mast. In coastal areas, with abundant food and high bear density, home ranges are smallest, averaging less than 200 km ” for males and less than 100 km? for females. Male home ranges are typically three to four times larger than those of females; both sexes increase their ranges during the mating season to maximize overlap with potential mates. Bear density and home range overlap are high in coastal populations with abundant and predictable food (spawning salmon). In interior populations, with less abundant or more variable food, home ranges overlap less, and bears may be somewhat territorial. In extreme northern populations, where food resources are scarce, home ranges are large and indefensible, so overlap is high. Home range overlap is also positively associated with relatedness, because female offspring often settle near their mother, assuming part of their natal home range. Multigenerational, matrilineal assemblages occur in established populations, whereas females may be more prone to disperse and settle among unrelated individuals in expanding populations. Males disperse in either case, but their dispersal age (1-4 years old) is related to their growth rate, and dispersal distance is inversely related to bear density. In a low density, expanding population in Scandinavia, one-third to half the females dispersed,settling 15 km from the natal range, on average, and 80-90% of males dispersed, generally settling over 100 km and up to nearly 500 km away. Seasonal movements are common for both sexes. In mountainous terrain, regular seasonal altitudinalshifts correspond with changing food conditions at different elevations and habitats. Lateral movements to seasonally abundant food sources may involve large numbers of bears traveling along well-worn routes, akin to a migration. Movements to fall feeding areas, followed by returns to denning sites, are often direct and rapid: travels exceeding 20 km in twelve hours have been recorded. At rich feeding areas, such as salmon streams, females with cubs avoid places with a high density of males, apparently because of threats of infanticide.

Breeding. Mating is promiscuous, and generally occurs from mid-May to mid-July. Within individual populations, the breeding period in any given yearis narrower, typically about one month. Estrus can be as brief as one day to as long as a month, and male-female pairings can last from just a few hoursto three weeks. Copulation generally lasts 10-40 minutes, and induces ovulation. Implantation of the blastocyst is delayed until six to eight weeks prior to birthing, which usually occurs in January or February, while the mother is hibernating in a secluded den. Food conditions, especially the proportion of meat (particularly salmon) in the diet, largely affect reproductive rates. Average age offirst birthing varies among populations from fourto ten years, and average litter size varies from 1-3-2-5 cubs. Maximum littersize is five. Inter-birth intervals are as short as two years in some European populations, more typically three years and sometimes more than four years in North America, and averages 5-7 years in a high altitude population in Pakistan. Extended litter intervals result from mothers spending extra time to raise cubs in poorer habitats. Offspring generally remain with the mother until she breeds; however, where inter-birth intervals are greatly extended, mothers may recoup for a year or more without offspring. Females continue to produce cubs until their mid to late 20s, but may live another ten years after that.

Status and Conservation. Only populations in central Asia ( Mongolia to the Himalayas, China, Nepal, Bhutan) fall under CITES Appendix I; all others are CITES Appendix II. The species as a whole is not considered threatened by The IUCN Red List (Least Concern), but some individual European populations are separately red-listed (Vulnerable-Critically Endangered), and other threatened populations will be added in the near future. These small populations tend to exist in remnant wild areas surrounded by more extensive human development, which act as mortality sinks. Forty-seven countries in North America, Europe, and Asia are inhabited by Brown Bears. During the past 500 years they have been extirpated from 17 other countries, including large parts of Europe, North Africa, the Middle East, and Mexico. In the lower 48 states of the USA, they were exterminated from more than 98% of their original range within 100 years of the arrival of European settlers, and have not since recovered. The total world population is estimated to exceed 200,000. Fairly reliable population estimates exist for several areas in North America ( USA 33,000; Canada 25,000) and Europe (14,000, excluding Russia), but for few areas in Asia. Russia has the largest number of Brown Bears, believed to exceed 100,000. The species is relatively abundant in more northern parts of its distribution, but smaller, fragmented populations exist farther south. Populations are sufficiently large to sustain legal hunting in Russia, several former Soviet Republics, Japan (Hokkaido Island), Canada, Alaska ( USA), and several European countries. Conversely, populations with fewer than 100 individuals exist along the USA-Canadian border and in southern Europe where several small, isolated populations persist: two in the Pyrenees ( France and Spain), one with less than 10 bears and the other with about 20, two populations in the Cantabrian Mountains ( Spain) containing 20-30 and 80-100 bears, a population in the Appenine Mountains ( Italy) with 40-50 bears, and in the the Alps ( Italy, Austria, and Slovenia) with 35-40 bears. Small, disconnected populations are also scattered across southern Asia, and in some areas even the present existence of this species is unknown ( Bhutan, Iraq). As wide-ranging omnivores, Brown Bears are attracted to areas with human-related foods, where they may threaten life and damage property (livestock, cropfields) and may be killed as a consequence. Small numbers of mortalities, especially adult females, can threaten the viability of small, isolated populations. Most small populations are legally protected by national laws and international agreements, but with varying degrees of enforcement. Moreover, even where hunting is banned, other sorts of human-caused mortality (management removals, self-defense, malicious killing, poaching, mistaken hunting of Black Bear) dominate the population dynamics of these bears. Reintroductions and population augmentations have helped to restore numbers and expand geographic range in the USA and Western Europe. Numerous protected areas around the world have Brown Bears, but few are large enough to support a self-sustaining population; therefore, Brown Bear conservation must be integrated with many other human land-uses.

Bibliography. Bellemain, Nawaz et al. (2007), Bellemain, Swenson & Taberlet (2006), Bromlei (1965), Brown (1985), Ciarniello et al. (2007), Clark et al. (2002), Craighead, F.C. (1976), Craighead, J.J. et al. (1995), Dahle & Swenson (2003a, 2003b, 2003c), Doupé et al. (2007), Ferguson & McLoughlin (2000), Fernandez-Gil et al. (2006), Galbreath et al. (2007), Garshelis (2004), Garshelis et al. (2005), Groupe National Ours dans les Pyrénées (2008), Hall (1984), Hilderbrand, Jenkins et al. (1999), Hilderbrand, Schwartz et al. (1999), IUCN (2008), Japan Bear Network (2006), Kaczensky et al. (2006), Kasworm et al. (2007), LeFranc et al. (1987), Linnell et al. (2000), MacHutchon & Wellwood (2003), Mattson & Merrill (2002), McLellan & Hovey (1995, 2001), McLellan, Hovey et al. (1999), McLellan, Servheen & Huber (2007), McLoughlin, Case et al. (1999), McLoughlin, Ferguson & Messier (2000), Miller et al. (2006), Mowat & Heard (2006), Munro et al. (2006), Nellerman et al. (2007), Nielsen, Herrero et al. (2004), Nielsen, Stenhouse & Boyce (2006), Pasitschniak-Arts (1993), Proctor et al. (2004, 2005), Rode et al. (2006), Saarma etal. (2007), Schwartz, Haroldson et al. (2006), Schwartz, Keating et al. (2003), Schwartz, Miller & Haroldson (2003), Servheen et al. (1999), Seryodkin et al. (2003), Steen, Bellemain et al. (2005), Steen, Zedrosser et al. (2006), Swenson et al. (2000), Talbot & Shields (1996), Vaisfeld & Chestin (1993), Valdiosera, Garcia et al. (2007), Valdiosera, Garcia-Garitagoitia et al. (2008), Van Daele (2007), Waits et al. (1998), Xu et al. (2006), Zager & Beecham (2006), Zedrosser et al. (2007).

Figures

7. Brown Bear (Ursus arctos), 8. Polar Bear (Ursus maritimus)

Subspecies and Distribution. U. a. arctos Linnaeus, 1758 — Europe and W Russia . U. a. alascensis Merriam, 1896 — most of Alaska (excluding Alaska Peninsula, SE panhandle & Kodiak Island group). U. a. beringianus Middendorff, 1853 — NE Russia (Kamchatka Peninsula & N Kuril Islands northward through the Koryak Autonomous District, and along W coast of the Sea of Okhotsk). U. a. collaris Cuvier, 1824 — Russia (Siberia, from E of the Yenisey River to the Bering Sea, but excluding Kamchatka and more southern parts of the Russian Far East), N Mongolia . U. a. dalli Merriam, 1896 — SE Alaska (N of Alexander Archipelago). U. a. gyas Merriam, 1902 — Alaska peninsula. U. a. horribilis Ord, 1815 —W Canada (Yukon, North-West Territories, British Columbia & Alberta), inland W USA (extirpated from S Wyoming to Mexico ). U. a. isabellinus Horsfield, 1826 — N India , Pakistan , Afghanistan , N to Kazakhstan and Mongolia (Gobi Desert). U. a. lasiotus Gray, 1867 — Russia (Southern Kuril Islands, Sakhalin, Ussuri/ Amur river region of the Russian Far East), NE China , North Korea , and Japan (Hokkaido). U. a. middendorffi Merriam, 1896 — Alaska (Kodiak Island & nearby islands). U. a. pruinosus Blyth, 1853 — Tibetan Plateau, China , N Nepal . U. a. sitkensis Merriam, 1896 — SE Alaska (Alexander Archipelago & adjacent coastal area). U. a. stikeenensis Merriam, 1914 — W Canada (W British Columbia), and formerly W USA (W Washington and Oregon). U. a. syriacus Hemprich & Ehrenberg, 1828 — Middle East, from Turkey to Iran (extirpated in Syria ), Caucasus mountains of Russia , Georgia , Armenia and Azerbaijan .