Is the hippo a member of the horse family?
No. The hippopotamus is not very closely related to horses,
although of course both species are mammals. The hippopotamus is a
type of even-toed ungulate and is thus more closely related to
camels, cows, and pigs, than it is to horses. Horses technically do
not have toes, but the hoof of a horse is equivalent to a highly
developed toenail of a single toe, making horses a kind of odd toed
ungulate.