The Bovine family is known in fossils from the Pre-Miocene, around 20 Ma. The earliest bull-like species, such as the Eotragus, were small animals, somewhat similar to today’s Gazelle and probably lived in a woodland habitat. The number of Bovine species increased strongly in Late Miocene, when many species adapted to grassland and more open environment.
The greatest number of modern Bovine species is found in Africa, while the predominantly large but less diverse population belongs to Asia and North America. It is thought that many of these family species evolved in Asia but could not survive due to the hunting of humans from Africa at the end of the Pleistocene. In contrast, African species have thousands or millions of years to adapt to the gradual development of human hunting skills. However, many of the species in this family were domesticated to be of Asian origin (goats, sheep, buffaloes, and Western cattle). This may be because these species are less fearful of humans and easier to command.
A small number of modern species in the American Cattle family are relatively recent along the Bering land bridge, but they still arrived in the area before humans arrived.
See more at: Hello Sweet Cheeks Cow Poster