History of the domestic sheep exact line of descent between domestic sheep and their wild ancestors is unclear. The most common hypothesis states that "Ovis aries" is descended from the Asiatic ("O. orientalis") species of mouflon. A few breeds of sheep, such as the Castlemilk Moorit from Scotland, were formed through crossbreeding with wild European mouflon. The urial ("O. vignei") was once thought to have been a forebear of domestic sheep, as they occasionally interbreed with mouflon in the Iranian part of their range. However, the urial, argali ("O. ammon"), and snow sheep ("O. nivicola") have a different number of chromosomes than other Ovis species,
Somali wild ass home to eleven Somali Wild Asses, the largest population of Somali Wild Asses in North America. The park received its first herd from the Basel Zoo in 1981. Their first foal was born in 1986. Since then, 49 foals have been born, the most recent being a female born on March 17, 2018. San Diego Zoo Global also works to help save this endangered species in the wild. Domestic donkeys found in Italy are typically descended from the Somali wild ass, as opposed to those from other European countries where domesticated stock are usually descended from the Nubian wild ass.