Equus (genus)
Equus is a genus of mammals in the family Equidae, which includes horses, donkeys, and zebras. Within Equidae, "Equus" is the only recognized extant genus, comprising seven living species. The term equine refers to any member of this genus, including horses. Like Equidae more broadly, "Equus" has numerous extinct species known only from fossils. The genus most likely originated in North America and spread quickly to the Old World. Equines are odd-toed ungulates with slender legs, long heads, relatively long necks, manes (erect in most subspecies), and long tails. All species are herbivorous, and mostly grazers, with simpler digestive systems than ruminants, but able to subsist on lower-quality vegetation.
Deer
The subfamily Capreolinae consists of 9 genera and 36 species, while Cervinae comprises 10 genera and 55 species. Hydropotinae consists of a single species, the water deer ("H. inermis"); however, a 1998 study placed it under Capreolinae. The following list is based on molecular and phylogenetic studies by zoologists such as Groves and Grubb.The following is the classification of the extinct cervids with known fossil record:Deer were an important source of food for early hominids. In China, "Homo erectus" fed upon the sika deer, while the red deer was hunted in Germany. In the Upper Palaeolithic, the reindeer was the staple food for Cro-Magnon people, while the cave paintings at Lascaux in southwestern France include some 90 images of stags.