Goats belong, scientifically, to the Bovidae family within the suborder of ruminants (chevrotain, deer, elk, caribou, moose, giraffe, okapi, antelope), who besides the other suborders of camels, swine and hippopotamuses make up the order of eventoed hoofed animals called artiodactyla. They evolved 20 million years ago in the Miocene Age, much later than horses, donkeys, zebras, tapirs, rhinoceroses, who make up the order of uneventoed hoofed animals; and the hyrax, elephants, manatees who make up the ancient near-hoofed animals. All these are herbivorous mammals, i.e., they live from plants and nurse their young with milk from an external gland after the young is born, having been carried in pregnancy to term relatively long in an internal uterus with a complex, nourishing placenta.
Goats and sheep make up a tribe within the Bovidae family called Caprini that include six goat, six sheep and five related species. Goats have a 2n chromosome set number of 60 while domestic sheep have a 2n set of 54; yet living hybrids of the two genera have been reported. The six species of goats can be distinguished by their horn shapes:
1. Capra aegagrus, the wild (or bezoar) goat of Near East Asia has scimitar-shaped horns with a sharp
anterior keel and a few knobs interrupting it.
2. Capra ibex, the ibex of the Alps, Siberia and Nubia has scimitar shaped horns with a flatter front and
many transverse ridges.
3. Capra falconeri, the markhor of Central Asia has sharpkeeled horns that are twisted into open or tight
4. Capra pyrenaica, the Spanish goat has outward-upward curving horns with a sharp posterior keel.
5. Capra cylindricornis, the Dagestan tur of the Caucasus mountains has round outward-back inward
6. Capra hircus, the domestic goat evolved principally from capra aegagrus, except for Angora, Cashmere
goats, and Damascus types who descended from capra falconeri.