Asian black bear
Five black bear populations, occurring in Kyushu, Shikoku, West-Chugoku, East-Chugoku and Kii areas, were listed as endangered by the Environmental Agency in the Japanese Red Data Book in 1991. Small isolated populations in the Tanzawa and Shimokita areas of mainland Honshū were listed as endangered in 1995. Beyond recognising these populations as endangered, there is still a lack of efficient conservation methods for Japanese black bears.
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.