Sheep, goats and musk oxen belong to one family that loves extreme terrain
A grey goral barely a metre long and a musk ox that can top 650 kilograms in captivity are close relatives. Both belong to the caprines, the group that gave us sheep and goats, and most of its members thrived during the ice ages by colonising places other grazers avoided.
Caprines are a branch of the bovid family, the ruminants that also include cattle and antelopes. Some older classifications gave them a family of their own, but today they are usually treated as a subfamily or tribe within the bovids. Besides domestic sheep and goats, the group includes the so-called goat antelopes: the North American mountain goat, built for sheer rocky slopes; the musk ox, adapted to frozen tundra; and the urial, a wild sheep ranging across dry country between Kashmir and Iran. Domestic sheep are thought to descend from the Armenian mouflon.
Their ways of life fall along a spectrum. At one end are the resource defenders, such as serows: smaller, darker animals in which males and females look much alike, each guarding a small patch of rich food with dagger-like horns and scent marking. At the other end are the herding grazers, a more recently evolved type that includes sheep, true goats and musk oxen. They are bigger, highly social, and settle rank through elaborate dominance displays rather than territory, roaming widely over poor ground.
Fossils show caprines as far back as the Miocene, when they looked broadly like modern serows. Their real flowering came during the recent ice ages, as species specialised for mountains, deserts and the subarctic. Ancestral sheep settled foothills and plains, relying on flocking and running to escape predators, while goats took to steep cliffs where hunters struggle to follow. Many species have died out since the last ice age, probably largely because of people.
Source: Caprinae
