Bears, classified in family Ursidae, are doglike carnivorans characterized by large size, stocky legs, five nonretractile claws, shaggy hair, a large snout, and omnivorous diets. There are eight surviving species of bears: the Giant Panda (a vegetarian), the Spectacled Bear (a relatively small bear native to western South America), the Brown Bear (the most familiar bear), the American Black Bear (somewhat smaller than the Brown Bear), the Polar Bear (one of the largest extant land carnivores), the Asiatic Black Bear (closely related to the American Black Bear), the Sloth Bear (an arboreal bear that lives in lowland forests on the Indian subcontinent), and the Sun Bear (the smallest bear, with short hair, that lives in the tropical forests of Southeast Asia).
Members of the family Ursidae display an interesting variety of sizes and diets, despite there being only eight species. Sun Bear males only weigh 66-112 lb (30-51 kg), while both the Polar Bear and Brown Bear weigh up to 1,500 lb (680 kg). Though the Polar Bear is often cited as the largest extant terrestrial carnivore, it can be matched by the Brown Bear, or exceeded by large saltwater crocodiles, though these spend a lot of time in the water. It is better labeled one of the two largest extant exclusively terrestrial carnivores.
Bears, which split from their canid ancestors about 38 million years ago, have been dominant land animals for many millions of years, in both North America and Eurasia. Though there exist many larger animals in the bear's range, such as hippos, rhinos, and elephants, bears are particularly notable for being more numerous than all of these, having a wider range, and being of greater danger to humans. The Brown Bear has been hunted since prehistoric times for its meat and fur, and features prominently in world mythology.
With native species on every continent except Africa, Australia, and Antarctica, bears have an extensive range that testifies to their evolutionary success. Except for the Giant Panda, which exclusively eats bamboo, and the Polar Bear, which is exclusively carnivorous, bears have a flexible omnivorous diet, including fruits, fresh shoots, nuts, small invertebrates, and vertebrates such as rodents and fish. They are among the most widely distributed animals, found from Argentina to the farthest reaches of the Arctic.
Michael is a longtime InfoBloom contributor who specializes in topics relating to paleontology, physics, biology, astronomy, chemistry, and futurism. In addition to being an avid blogger, Michael is particularly passionate about stem cell research, regenerative medicine, and life extension therapies. He has also worked for the Methuselah Foundation, the Singularity Institute for Artificial Intelligence, and the Lifeboat Foundation.