Asian black bear
Biologically and morphologically, Asiatic black bears represent the beginning of the arboreal specializations attained by sloth bears and sun bears. Asiatic black bears have karyotypes nearly identical to those of the five other ursine bears, and, as is typical in the genus, they have 74 chromosomes. From an evolutionary perspective, Asiatic black bears are the least changed of Old World bears, with certain scientists arguing that it is likely that all other lineages of ursine bear stem from this species. Scientists have proposed that Asiatic black bears are either a surviving, albeit modified, form of "Ursus etruscus", specifically the early, small variety of the Middle Villafranchian (Upper Pliocene to Lower Pleistocene) or a larger form of "Ursus minimus", an extinct species that arose 4,000,000 years ago. With the exception of the age of the bones, it is often difficult to distinguish the remains of "Ursus minimus" with those of modern Asiatic black bears.
Asian black bear
Asiatic black bears are omnivorous, and will feed on insects, beetle larvae, invertebrates, termites, grubs, carrion, bees, eggs, garbage, mushrooms, grasses, fruits, nuts, seeds, honey, herbs, acorns, cherries, dogwood, and grain. Although herbivorous to a greater degree than brown bears, and more carnivorous than American black bears, Asiatic black bears are not as specialized in their diet as pandas are: while pandas depend on a constant supply of low calorie, yet abundant foodstuffs, black bears are more opportunistic and have opted for a nutritional boom-or-bust economy. They thus gorge themselves on a variety of seasonal high calorie foods, storing the excess calories as fat, and then hibernate during times of scarcity. Black bears will eat pine nuts and acorns of the previous year in the April–May period. In times of scarcity, they enter river valleys to gain access to hazelnuts and insect larvae in rotting logs. From mid-May through late June, they will supplement their diet with green vegetation and fruit. Through July to September, they will climb trees to eat bird cherries, pine cones, vines and grapes. On rare occasions they will eat dead fish during the spawning season, though this constitutes a much lesser portion of their diet than in brown bears. In the 1970s, black bears were reported to kill and eat Hanuman langurs in Nepal. They appear to be more carnivorous than most other bears, including American black bears, and will kill ungulates with some regularity, including domestic livestock. Wild ungulate prey can include muntjacs, serow, takin, wild boar and adult water buffaloes, which they kill by breaking their necks.