Crow, Yukon, Canada, and at Cripple Creek Sump, Fairbanks, Alaska. The age is not agreed upon but could date to one million years ago. Considerable morphological diversity existed among wolves by the Late Pleistocene. They had more robust skulls and teeth than modern wolves, often with a shortened snout, a pronounced development of the temporalis muscle, and robust premolars. It is proposed that these features were specialized adaptations for the processing of carcass and bone associated with the hunting and scavenging of Pleistocene megafauna. Compared with modern wolves, some Pleistocene wolves showed an increase in tooth breakage similar to that seen in the extinct dire wolf. This suggests they either often processed carcasses, or that they competed with other carnivores and needed to consume their prey quickly. Compared with those found in the modern spotted hyena, the frequency and location of tooth fractures in these wolves indicates they were habitual bone crackers. Genomic studies suggest modern wolves and dogs descend from a common ancestral wolf population that existed 20,000 years ago. A 2021 study found that the Himalayan wolf and the Indian plains wolf are part of a lineage that is basal to other wolves and split from them 200,000 years ago. Other wolves appear to have originated in Beringia in an expansion that was driven by the huge ecological changes during the close of the Late Pleistocene. A study in 2016 indicates that a population bottleneck was followed by a rapid radiation from an ancestral population at a time during, or just after, the Last Glacial Maximum. This implies the original morphologically diverse wolf populations were out-competed and replaced by more modern wolves. A 2016 genomic study suggests that Old World and New World wolves split around 12,500 years ago followed by the divergence of the lineage that led to dogs from other Old World wolves around 11,100–12,300 years ago. An extinct Late Pleistocene wolf may have been the ancestor of the dog, with the dog's similarity to the extant wolf being the result of genetic admixture between the two. The dingo, Basenji, Tibetan Mastiff and Chinese indigenous breeds are basal members of the domestic dog clade. The divergence time for wolves in Europe, the Middle East, and Asia is estimated to be fairly recent at around 1,600 years ago. Among New World wolves, the Mexican wolf diverged around 5,400 years ago. Admixture with other canids In the distant