The horse is a hooved mammal, a breed of the family Equidae. The horse has evolved over the past 45 to 55 million years from a small multi-toed creature into the large, single-toed animal of today. Humans began to control horses around 4000 BC, and their domestication is supposed to have been common by 3000 BC. Although most horses today are domesticated, there are still rare populations of the Przewalski’s Horse, the only remain true wild horse, as well as more common populations of feral horses which live in the wild but are descended from disciplined relatives. There is an wide, specialized vocabulary used to describe equine-related concepts, covering everything from anatomy to life stages, size, colors, markings, breeds, locomotion, and behaviour.