|Scientific Name:||Ursus americanus|
|Species Authority:||Pallas, 1780|
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor/s:||Garshelis, D.L., Crider, D. & van Manen, F. (IUCN SSC Bear Specialist Group)|
|Reviewer/s:||McLellan, B.N. & Garshelis, D.L. (Bear Red List Authority)|
This species is widespread, with a large global population estimated at more than twice that of all other species of bears combined. Moreover, in most areas populations are expanding numerically and geographically. Threats exist only in a few isolated places.
|Range Description:||American black bears are found through much of Canada, the United States, and the northern half of Mexico. Although they were extirpated from large portions of their historic range because of habitat loss and (mainly intentional) overexploitation, their occupied range has been expanding in recent years (Pelton et al. 1999, Williamson 2002). The species has, nevertheless been extirpated from large parts of its former range, especially in the Midwest of the United States, and in Mexico. American black bears presently occupy all provinces and territories of Canada, except Prince Edward Island (where they were extirpated in 1937), 41 U.S. states (with occasional sightings in at least 3 others), and 8 states of northern Mexico. The species never existed outside of these three countries.|
Native:Canada; Mexico; United States
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||During the past two decades, most American black bear populations have grown both numerically and geographically (Williamson 2002). Sixty percent of U.S. and Canadian states and provinces report increasing populations, and all other populations appear to be either stable or fluctuating with no clear trend (Garshelis and Hristienko 2006). Based on sums of estimates for individual states, the total U.S. population, excluding Alaska, is estimated at somewhat greater than 300,000. No reliable estimate exists for numbers of black bears in Alaska, although most authorities presume there to be 100,000–200,000 animals. Similarly, large populations in some parts of Canada are not reliably known, but countrywide estimates centre around 450,000 (principally in British Columbia, Ontario, and Québec). Thus, the total number of black bears in North America is likely within the range 850,000–950,000. No population estimates exist for the country of Mexico, although some areas within Mexico have high and increasing black bear densities (SEMARNAP 1999, Doan-Crider 2003).|
|Habitat and Ecology:||
American black bears are primarily a species of temperate and boreal forests, but they also range into subtropical areas of Florida and Mexico as well as into the subarctic. They live at elevations ranging from sea level to 3,500 m, and inhabit areas as diverse as dry Mexican scrub forests, Louisiana swamps, Alaskan rainforests, and Labrador tundra (where they occupy the typical niche of the brown/grizzly bear [U. arctos]; Veitch and Harrington 1996). Between these extremes they occupy assorted deciduous and coniferous forest types, each providing a different array of foods.
The American black bear is a generalist, opportunist, omnivore. Depending on location and season, they consume herbaceous vegetation, roots, buds, numerous kinds of fleshy fruits, nuts, insects in life stages from egg to adult, and vertebrates from fish to mammals, including their own kills as well as carrion. Moreover, they readily consume various human-related foods, from garbage and birdseed to a variety of agricultural products, including standing corn and oats just before harvest, apples, and honey and brood in apiaries. The ability of black bears to vary their diet with the circumstances has enabled them to persist not only in a diversity of habitat types, but also in highly fragmented forested areas in proximity to humans (Pelton 2003).
A key habitat feature in many areas is a source of fall mast that enables black bears to increase their fat reserves in preparation for winter. Historically, American chestnuts (Castanea dentata) likely were a key fall food in eastern North America, but since a blight eliminated this food source in the early and mid 1900s, oak (Quercus spp.) acorns and beechnuts (Fagus grandifolia) have become the principal fall foods for bears throughout this region (Vaughan 2002). In areas where oaks and beech are absent or uncommon, hazelnuts (Corylus spp.), whitebark pine nuts (Pinus albicaulis), madrone (Arbutus xalapensis), mansanita (Arctostaphylos spp.), huckleberries (Vaccinium spp.), buffalo berries (Shepherdia canadensis) or other fruits, or sometimes meat, are the fall dietary mainstays. In the southwestern U.S. and in Mexico, succulents such as yucca (Yucca spp.) and cacti also play important roles in providing food, especially during drought (Doan-Crider 2003).
American black bears hibernate for up to 7 months in the northern portions of their range, but considerably shorter in more southern areas. In some southern areas, where food is available year-round, they may remain active during winter. However, all parturient females den and give birth to cubs, typically in January–February. Although mating occurs in May–July, implantation is delayed and active gestation is only 2 months. Females give birth beginning at age 3–8 years, depending on food availability and hence their body weight, and can produce cubs every other year (in places with less food, this interval is often extended to 3 years). Average litter size is approximately 2.5 cubs in eastern and 2.0 cubs in western North America (Alt 1989).
Through most of its range, this species is not threatened. Legal hunting is well controlled by state and provincial agencies. American black bears are harvested as a game species in all 12 Canadian provinces and territories where they exist and in 28 or 29 (depending on whether New Jersey allows a season) U.S. states. The sport harvest for this species in Canada and the U.S. totals 40,000–50,000 annually. Currently, the black bear is not hunted in Mexico, but some conditional permits are allowed for depredation cases.
A few small, isolated populations of American black bears may be threatened with extirpation, simply due to small population size and the effects of fluctuating food (and in some cases water) resources. In one unusual case, a black bear population on a large island in Québec was extirpated apparently from introduced deer excessively browsing berry-producing shrubs, and thus eliminating an essential food supply for the resident bears (Côté 2005). However, most small, isolated populations are in southern U.S. and northern Mexico. In a recent dramatic case, bears from Big Bend National Park, an isolated population in southwestern Texas, made long-range movements to Chihuahua and Coahuila, Mexico, apparently in search of better fall mast. Such movements, especially in fall, are not unusual for black bears, but in this case most of the bears never returned; they either stayed in Mexico, died naturally when crossing the desert, or were poached. As a result, the entire population was reduced to 5–7 bears, including only 2 adult females (Hellgren et al. 2005). Since then, the population has rebounded, possibly by bears immigrating back. Other examples exist where small, seemingly isolated populations have persisted and even grown, from a combination of reproduction and occasional immigration events (Doan-Crider and Hellgren 1996, Onorato et al. 2004).
Conflicts with humans constitute another potential threat to bears in some areas. In years when natural food supplies are scarce, people may encounter, and frequently kill, large numbers of bears seeking substitute foods such as agricultural crops or garbage. As more people encroach upon bear habitat, and as bear numbers grow, the frequency of interactions between humans and bears likely will increase. Indeed, the number of black bear attacks on humans (including fatalities) seems to be increasing across North America (S. Herrero pers. comm.).
Increasing density of roads is another growing threat to American black bears. Not only do roads lead directly to mortalities from vehicular collisions, but they also provide greater access to hunters and potential poachers and may be barriers to bear movements (Wooding and Maddrey 1994).
A looming concern, but not a widespread problem in North America, is the poaching of bears for their paws and gall bladders, which can be sold commercially. Those products, particularly bile from gall bladders, are highly valued by practitioners of Traditional Chinese Medicine. Several U.S. states and Canadian provinces allow the sale of bear parts, taken legally by hunters either in that jurisdiction or transported into that jurisdiction from elsewhere (Williamson 2002). An argument can be made that this creates opportunities for an illicit commercial trade for poachers.
From the time of European settlement until well into the 20th century, American black bears were extensively and purposefully over-hunted with the goal of eliminating or severely reducing their numbers to limit damage to crops and livestock. Many state and provincial governments paid a bounty for killing black bears. Population recovery occurred only after those jurisdictions recognized a need to protect black bears as a big game species. Protection and recovery occurred state-by-state and province-by-province during 1902–1983 (Miller 1990). Afterwards, the number of bears killed was more closely regulated and, moreover, an infrastructure of agency personnel and hunters policed illegal take.
In Mexico all hunting seasons for American black bears have been closed since 1985, and the species is considered nationally endangered. Numerous conservation initiatives established by large private ranches and land cooperatives in northern Mexico have created large blocks of suitable habitat (e.g., oak-dominated forests) with protection from poaching (Doan-Crider 2003). Changing public attitudes toward bears in Mexico have also contributed to the recuperation and expansion of the species into historic range, including recolonization of areas of Texas that have long been devoid of bears (SEMARNAP 1999, Onorato et al. 2004).
In the southeastern U.S., where black bears occupy only about 20% of their historic range, population recovery was aided by the establishment of national parks and other protected areas in the Appalachian Mountains and the Coastal Plain (Pelton and van Manen 1997). These large areas protect the habitat (especially mast-producing trees) and restrict hunter access. Beginning in the early 1970s, additional areas were established where bear hunting was prohibited, linking protected areas to other forested lands, including many private lands. The resulting conglomerates serve as dedicated or defacto sanctuaries, especially for adult females, that are a source for bears expanding into other areas (Beringer et al. 1998).
In a few areas, populations of American black bears have either been augmented or reintroduced after former extirpation by transplanting bears from elsewhere. Reintroductions into Arkansas during the 1960s were highly successful: licensed hunters in this state now harvest several hundred bears annually, and Arkansas bears have expanded into neighbouring states. Augmentation of several populations in Louisiana during the 1960s likely contributed to population recovery there. The success of recent reintroduction efforts in southeastern Kentucky–north-central Tennessee (mid-1990s) and southeastern Arkansas (2000-2007) may not be known for some time (Clark et al. 2002).
The Louisiana black bear (U. a. luteolus), a subspecies of American black bear, was listed as threatened under the U.S. Endangered Species Act in 1992 because of severe loss and fragmentation of its habitat combined with unsustainable human-caused mortality (Bowker and Jacobson 1995). Some evidence exists that this native subspecies may have interbred with black bears introduced from Minnesota, and the two subspecies can no longer be distinguished. Therefore, all bears within the historic range of the Louisiana black bear, from east Texas to southern Mississippi, are protected due to their similarity of appearance to a threatened taxon. Much of the bottomland hardwood forest that the Louisiana black bear historically inhabited was converted to agriculture. Remnant bottomland hardwoods are now protected, some marginal farmland is being replanted with hardwood trees, and the bear range is being expanded by capturing individuals from within their present range and moving them to uninhabited areas of their former range. These efforts are further enhanced through public information and education. This management program is organized by a broad coalition of state and federal agencies, conservation groups, forestry and agricultural industries, and private landowners. As a result, this subspecies has been noticeably increasing in numbers and distribution in all three range states.
Another subspecies of black bear (U. a. floridanus) is listed as threatened by the state of Florida. A previous petition for listing this subspecies under the U.S. Endangered Species Act was denied because it was deemed that extant populations were sufficiently large and state regulations adequate to protect it from extirpation in most areas. Corridors, either existing or proposed, are important for linking some small, isolated populations with larger populations (Larkin et al. 2004, Dixon et al. 2006).
In British Columbia much conservation attention has been directed toward the Kermode subspecies (U. a. kermodei). This animal is commonly referred to as the “spirit bear” because it possesses a gene that when homozygous is manifested as white pelage (Ritland et al. 2001). White-phased animals have long been protected from hunting. A large system of protected areas was established in 2006 (Great Bear Rainforest Agreement) to ban or severely restrict logging within >200,000 ha of coastal temperate rainforest inhabited by this subspecies of black bear, as well as by brown bears. Additionally, the spirit bear was selected as the official provincial mammal of British Columbia.
Since 1992 all American black bears have been listed in Appendix II of CITES, under the similarity of appearance provision (Article II, para 2b). This listing stipulates that documentation of legal harvest is necessary for the import and export of body parts in order to prevent these from being confused as parts from illegally obtained bears. This listing was not designed to protect American black bears, but rather other species of threatened bears, particularly the Asiatic black bear (U. thibetanus), whose parts might otherwise be sold under the guise of being from American black bear.
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Beringer, J., Seibert, S. G., Reagan, S., Brody, A. J., Pelton, M. R. and Vangilder, L. D. 1998. The influence of a small sanctuary on survival rates of black bears in North Carolina. Journal of Wildlife Management 62: 727-734.
Bowker, B. and Jacobson, T. 1995. Louisiana black bear Ursus americanus luteolus recovery plan. U.S. Fish and Widlife Service, Atlanta, Georgia, USA.
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Doan-Crider, D. L. 2003. Movements and spaciotemporal variation in relation to food productivity and distribution, and population dynamics of the Mexican black bear in the Serranias Burro, Coahuila, Mexico. Ph.D. Thesis, Texas A&M University-Kingsville.
Doan Crider, D. L. and Hellgren, E. C. 1996. Population characteristics and winter ecology of black bears in Coahuila, Mexico. Journal of Wildlife Management 60: 398-407.
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|Citation:||Garshelis, D.L., Crider, D. & van Manen, F. (IUCN SSC Bear Specialist Group) 2008. Ursus americanus. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 11 March 2014.|
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