How to Identify Skeletons of Bears
There are eight living species of bear: the spectacled bear, the polar bear, the giant panda, the American black bear, the brown (or grizzly) bear, the Asian black bear, the sun bear and the sloth bear. These species vary greatly in size and distribution, so differentiating skeletal remains to the species level is not difficult, as long as the skull is present. Only the brown bear and the American black bear, which have overlapping habitats, are nonthreatened species. However, many subspecies exist, and classifying a specimen into a subspecies based on skeletal remains can be difficult, even with a guide to bear skulls.
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Instructions
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Ensure that the skeleton in question belongs to a bear. If the skull is present, this is quite easy. A dog skull may closely resemble a bear skull, but there is a wide, obvious gap between the canines and the premolars of a bear. Canines are the sharp, pointed fanglike teeth. Premolars, or bicuspids, are the teeth with two raised ridges, found just after the canines. Dogs have a gap, but it is much less obvious, especially when viewed from the side. Bears and dogs often have the same number of teeth. They differ in the fact that bears have two upper molars on each side while dogs have three upper molars on each side. Molars are the flattened back teeth with more than two cusps, or raised ridges, on the chewing surface of the tooth.
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Identify possible species by location. The polar bear is distributed in the Arctic Circle. The sun bear, giant panda, sloth bear and Asian black bear are all found in southern Asia. Only the spectacled bear is found in South America. The most widespread bear is the brown bear, which is found throughout North America and Eurasia. The American black bear is only found in North America. When species share the same habitat, they are called sympatric species. The Asian black bear, sun bear and sloth bear are sympatric in far eastern India. The brown bear is sympatric with the Asian black bear in northern China, as well as the American black bear throughout western Canada and Alaska and the polar bear in northern Canada and Alaska.
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Differentiate between sympatric species by examining the skull. In most North American bears, the molars will be broad and flat, reflecting their omnivorous diet. Polar bears, however, have sharp, jagged molars, as their diet is strictly carnivorous. If the molars are flattened, measure the last upper molar. If it is less than 31 mm, the skull belongs to a black bear. If it is 38 mm or longer, the skull belongs to a brown bear. Due to the rarity of Asian bears, it is unlikely that any unidentified skeletal remains belong to an Asian species.
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Tips & Warnings
Any species of bear found outside North America is rare. Most likely, you want to find a key to the skulls of North American bears to identify a particular subspecies. A good example is the "Illustrated Key to Skulls of Genera of North American Land Mammals" by J. Knox Jones.
If no skull is present, the task of identifying skeletal remains becomes more difficult, especially if they are incomplete or scattered. Bear bones have even been mistaken for human bones. In these cases, consult a natural history museum. A mammalogist should be able to identify the bones.
Of the eight extant species of bear, six are considered vulnerable or endangered. These bears are protected in most countries and even if you are not responsible for the death of the animal, possessing the animal's remains may be illegal.
References
Resources
- Photo Credit Grizzly Bear image by Ryan LeBaron from Fotolia.com
