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.
Equid hybrid
From the 20th century equid hybrids were being created., though breeding for mules and hinnies had been going on since ancient times. The first crossbreeding was with zebras and donkeys. Equid hybrids can be traced back to Africa where there are vast amount of equid species which resulted in natural crossing creating hybrid species. These hybrids were found to be more efficient than the original species because they poses certain traits of both species so scientists began to experiment by crossing other species of horse family and categorizing them as Equid Hybrids. Equid hybrids are now bred commercially. Mules bred from mammoth studs and stock or draft mares can be as large as seventeen hands and are as strong as a normal horse. Other mules are bred for pets or for entertainment such as zoo, these are the miniature horses or miniature donkeys.