entrance of Homo sapiens. The large Late Pleistocene carnivores that were more carnivorous than their competitors faced greater vulnerability to extinction. The Beringian cave lion, saber-toothed cat, and short-faced bear went extinct at the same time as their large megafaunal prey. The omnivorous coyote, American black bear, brown bear, puma and bobcat survived. Both the Beringian wolf and the dire wolf went extinct in North America, leaving only the less carnivorous and more gracile form of the wolf to thrive. One extinction theory holds that the Beringian wolf was outcompeted and replaced by the ancestor of the modern gray wolf. The radiocarbon dating of the skeletal remains from 56 Beringian wolves showed a continuous population from over 50,800 YBP until 12,500YBP, followed by one wolf dated at 7,600YBP. This indicates that their population was in decline after 12,500YBP, although megafaunal prey was still available in this region until 10,500YBP. The timing of this latter specimen is supported by the recovery of mammoth and horse DNA from sediments dated 10,500 YBP–7,600 YBP from the interior of Alaska, and steppe bison dated 5,400 YBP from the Yukon. The timing for the extinction of horses in North America and the minimum population size for North American bison coincide with the extinction of an entire wolf haplogroup in North America, indicating that the disappearance of their prey caused the extinction of this wolf ecomorph. This resulted in a significant loss of phenotypic and genetic diversity within the species. Haplotype is not extinct There are parts of Central Eurasia where the environment is considered to be stable over the past 40,000 years. In 2016 a study compared mDNA sequences of ancient wolf specimens with those from modern wolves, including specimens from the remote regions of North America, Russia, and China. One ancient haplotype that had once existed in both Alaska (Eastern Beringia 28,000YBP) and Russia (Medvezya "Bear" Cave, Pechora area, Northern Urals 18,000YBP) was shared by modern wolves found living in Mongolia and China (indicating a common maternal ancestor). The study found that the genetic diversity of past wolves was lost at the beginning of the Holocene in Alaska, Siberia, and Europe, and that there is limited overlap with modern wolves. The study did not support two wolf haplogroups that had been proposed by earlier studies. For the ancient wolves of North America, instead of an extinction/replacement model indicated by other studies, this study found