black bear

Asian black bear is the smallest bear in North America. The length of an adult is usually less than 6 feet and the height of a shoulder is about 2 to 3 feet. The weight of Asian black bear varies between 125 and 500 pounds. They have small eyes and round ears. My nose is long. Each foot has five very strong nails to tear, dig, and climb. It is enough to kill an adult deer simply by hitting the forefoot. It is a true carnivore, but if you leave it unchecked, it will be a big problem for humans.

The ancestors of American black bear and Asian black bear are separated from Sun Bear 4.58 mya. Then American black bear was separated from Asian black bear 4.08 mya. The fossil of the early American black bear was in the port of Kennedy, Pennsylvania, very similar to Asian seeds, but later specimens grew to the size of Grizzlies. From the Holocene to the present, the size of American black bear seems to shrink, but it is controversial for these fossil sample age.

Consistent with phylogenetic contradiction and D statistics, the DFOIL statistics found a gene flow between the ancestors of American black bear / brown bear / polar bear cactus and Asian black bears (FIG. 4, Table 1). Euroria bear overlaps with other bear species geographically and is widely distributed like Asian black bear. It was found in the fossil layer of 2.5 Ma - 1.0 Ma1, 31 in Europe. The broad geographical distribution will explain the almost equally strong gene flow from Asian black bear seen in D statistics to Brown bear (Supplementary Figure 14). Finally, there is a gene flow signal between America and Asian black bear. Gene flow can occur on the US side or Asian side of the Bering Strait, consistent with intra-species mitochondrial capture 2 (Figure 3). Most of weak gene flow signals are shown in Figure 1.