The American black bear (Ursus americanus), or simply black bear, is a species of medium-sized bear which is endemic to North America. It is the continent's smallest and most widely distributed bear species. It is an omnivore, with a diet varying greatly depending on season and location. It primarily inhabits forested regions, but may venture beyond forest boundaries in search of food. Individuals are occasionally drawn to human settlements due to the availability of easily accessible food sources.
The International Union for Conservation of Nature (IUCN) lists the American black bear as a least-concern species because of its widespread distribution and a large population, estimated to be twice that of all other bear species combined. Along with the brown bear (Ursus arctos), it is one of the two modern bear species not considered by the IUCN to be globally threatened with extinction.
Taxonomy The American black bear is not closely related to the brown bear or polar bear, though all three species are found in North America; genetic studies reveal that they split from a common ancestor 5.05 million years ago (mya). American and Asian black bears are considered sister taxa and are more closely related to each other than to the other modern species of bears.
Evolution The ancestors of American black bears and Asian black bears diverged from sun bears 4.58 mya. The American black bear then split from the Asian black bear 4.08 mya.Lisette Waits, David Paetkau, and Curtis Strobeck, "Overview" from Genetics of the Bears of the World. Chapter 3 of Bears: Status Survey and Conservation Action Plan, compiled by Christopher Servheen, Stephen Herrero and Bernard Peyton, IUCN/SSC Bear Specialist Group A small, primitive bear genus called protarctos (U. abstrusus) is the oldest known North American fossil member of the genus Ursus, dated to 4.95 mya. This suggests that U. abstrusus may be the direct ancestor of the American black bear, which evolved in North America.
The earliest American black bear fossils, from the Early Pleistocene of Port Kennedy, Pennsylvania, greatly resemble the Asian species, though later specimens grew to sizes comparable to grizzly bears. Once described as a precursor species (Ursus vitabilis), these specimens have been synonymized with U. americanus. The American black bear lived during the same period as the giant and lesser short-faced bears (Arctodus simus and A. pristinus, respectively) and the Florida spectacled bear (Tremarctos floridanus). These tremarctine bears evolved from bears that had emigrated from Asia to the Americas 7–8 mya. The giant and lesser short-faced bears are thought to have been heavily carnivorous and the Florida spectacled bear more herbivorous, while the American black bears remained arboreal omnivores, like their Asian ancestors. From the Holocene to the present, American black bears seem to have shrunk in size, but this has been disputed because of problems with dating these fossil specimens.
The American black bear's generalist behavior allowed it to exploit a wider variety of foods and has been given as a reason why, of these three genera, it alone survived climate and vegetative changes through the last Ice Age while the other, more specialized North American predators became extinct. However, both Arctodus and Tremarctos had survived several other, previous ice ages. After these prehistoric ursids became extinct at the end of the Pleistocene, American black bears, brown bears and polar bears were the only remaining bears in North America.
Hybrids American black bears are reproductively compatible with several other bear species and occasionally produce hybrid offspring. According to Jack Hanna's Monkeys on the Interstate, a bear captured in Sanford, Florida, was thought to have been the offspring of an escaped female Asian black bear and a male American black bear."Hybrid Bears". messybeast.com. In 1859, an American black bear and a Eurasian brown bear were bred together in the London Zoo, but the three cubs that were born died before they reached maturity. In The Variation of Animals and Plants Under Domestication, Charles Darwin noted:
A bear shot in autumn 1986 in Michigan was thought by some to be an American black bear/grizzly bear hybrid, because of its unusually large size and its proportionately larger brain case and skull. DNA testing was unable to determine whether it was a large American black bear or a grizzly bear.
Subspecies Sixteen subspecies are traditionally recognized; however, a 2015 genetic study did not support designating some of these, such as the Florida black bear, as distinct subspecies. Listed alphabetically according to subspecific name:
+ American black bear subspecies Image Scientific name Common name Distribution Description
Ursus americanus altifrontalis Olympic black bear the Pacific Northwest coast from central British Columbia through northern California and inland to the tip of northern Idaho and British Columbia
Ursus americanus amblyceps New Mexico black bear Colorado, New Mexico, western Texas and the eastern half of Arizona into northern Mexico and southeastern Utah
Ursus americanus americanus Eastern black bear Eastern Montana to the Atlantic coast, from Alaska south and east through Canada to Maine and south to Texas. Thought to be increasing in some regions. Common to Eastern Canada and the eastern U.S. wherever suitable habitat is found. A large-bodied subspecies; almost all specimens have black fur. May very rarely sport a white blaze on the chest.
Ursus americanus californiensis California black bear the mountain ranges of southern California, north through the Central Valley to southern Oregon Able to live in varied climates: found in temperate rain forest in the north and chaparral shrubland in the south. Small numbers may feature cinnamon-colored fur. Ursus americanus carlottae Haida Gwaii black bear or Queen Charlotte Islands black bear Haida Gwaii (formerly the Queen Charlotte Islands) and Alaska Generally larger than its mainland counterparts with a large skull and molars and found only in a black color phase.
Ursus americanus cinnamomum Cinnamon bear Colorado, Idaho, western Montana and Wyoming, eastern Washington and Oregon and northeastern Utah Has brown or reddish-brown fur, reminiscent of cinnamon.
Ursus americanus emmonsii Glacier bear or blue bear Southeastern Alaska Distinguished by its fur being silvery-gray with a blue luster found mostly on its flanks.
Ursus americanus eremicus East Mexican black bear Northeastern Mexico and U.S. borderlands with Texas. Most often found in Big Bend National Park and the desert border with Mexico. Numbers unknown in Mexico but are presumed to be very low. Critically Endangered.
Ursus americanus floridanus Florida black bear Florida, southern Georgia, Alabama and Mississippi (except the southern region) Has a light brown nose and shiny black fur. A white blaze on the chest is common in this subspecies. An average male weighs .
Ursus americanus hamiltoni Newfoundland black bear Newfoundland Generally bigger than its mainland relatives, ranging in size from and averaging . It has one of the longest hibernation periods of any bear in North America."Black Bear" , Parks Canada Known to favor foraging in fields of Vaccinium species.
Ursus americanus kermodei Spirit bear or island white bear, Kermode bear the central coast of British Columbia Approximately 10% of the population of this subspecies have white or cream-colored coats due to a recessive gene. The other 90% appear as normal-colored black bears. Ursus americanus luteolus Louisiana black bear Eastern Texas, Louisiana and southern Mississippi. The validity of this subspecies has been repeatedly disputed. Has relatively long, narrow and flat skull and proportionately large molars.Louisiana Black Bear (PDF). Retrieved September 15, 2011. Prefers bottomland forests and bayous as habitat. Ursus americanus machetes West Mexican black bear north-central Mexico Ursus americanus perniger Kenai black bear the Kenai Peninsula, Alaska Considered an "Apparently Secure Subspecies" by NatureServe. Ursus americanus pugnax Dall Island black bear Dall Island in the Alexander Archipelago, Alaska Ursus americanus vancouveri Vancouver Island black bear Vancouver Island, British Columbia Darker and slightly bigger than the other five subspecies found in British Columbia; it is most common in the north, but appears occasionally in the southern parts of Vancouver Island.
Distribution and population
Historically, American black bears occupied the majority of North America's forested regions. Today, they are primarily limited to sparsely settled, forested areas. American black bears currently inhabit much of their original Canadian range, though they seldom occur in the southern farmlands of Alberta, Saskatchewan and Manitoba; they have been extirpated on Prince Edward Island since 1937. Surveys taken in the mid-1990s found the Canadian black bear population to be between 396,000 and 476,000 in seven provinces; this estimate excludes populations in New Brunswick, the Northwest Territories, Nova Scotia and Saskatchewan. All provinces indicated stable populations of American black bears over the 2000s.
The current range in the United States is constant throughout most of the Northeast and within the Appalachian Mountains almost continuously from Maine to northern Georgia, the northern Midwest, the Rocky Mountain region, the West Coast and Alaska. However, it becomes increasingly fragmented or absent in other regions. Despite this, American black bears in those areas seem to have expanded their range in recent decades, such as with sightings in Ohio, Illinois, southern Indiana, and western Nebraska. Sightings of itinerant black bears in the Driftless Area of southeastern Minnesota, northeastern Iowa, and southwestern Wisconsin are common. In 2019, biologists with the Iowa Department of Natural Resources confirmed documentation of an American black bear living year-round in woodlands near the town of Decorah in northeastern Iowa, believed to be the first instance of a resident black bear in Iowa since the 1880s.
Surveys taken from 35 states in the early 1990s indicated that American black bear populations were either stable or increasing, except in Idaho and New Mexico. The population in the United States was estimated to range between 339,000 and 465,000 in 2011, though this estimate does not include data from Alaska, Idaho, South Dakota, Texas or Wyoming, whose populations were not recorded in the survey. California has the largest population of the species in any of the 48 contiguous United States. The estimated 25,000-35,000 black bears in 2017 grew to 60,000 by 2026. In 2020 there were about 1,500 bears in Great Smoky Mountains National Park, where the population density is about two per square mile. In western North Carolina, the black bear population has increased from about 3,000 in the early 2000s to over 8,000 in the 2020s.
As of 1993, known black bear populations in Mexico existed in four areas, though knowledge on the distribution of populations outside those areas has not been updated since 1959. Mexico is the only country where the species is classified as "endangered".
Habitat