Asian black bear
Along with sun bears, Asiatic black bears are the most typically used species in areas where bears are either used in performances or as pets. Asian black bears have an outstanding learning ability in captivity, and are among the most common species used in circus acts. According to Gary Brown:
American black bear
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. The earliest American black bear fossils, which were located in Port Kennedy, Pennsylvania, greatly resemble the Asian species, though later specimens grew to sizes comparable to grizzly bears. 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.