Our hoofed mammals are all large herbivores.
They can conveniently be divided into two families: the cattle family containing mountain goats and bighorn sheep; the deer family containing elk, mule deer, white-tailed deer, moose, and caribou. In both families, the male is generally larger and bears either horns or antlers.
The horns of the cattle family are a hard permanent outgrowth of a core of bone encased in keratinized skin. Among bighorn sheep, the female also grows horns, but they are small and they don’t bend around to form a half circle as they do in the male.
The antlers of the deer family differ greatly from the horns of the cattle family. Antlers are shed annually; they have multiple branches, they are not covered with keratin, but vascular skin called velvet.
There are an even number of toes on the hooves: two for the cattle family; four for the deer family. However, the four toes of the latter are composed of two large toes and two set farther back and called dewclaws.