Also known as reindeer, caribous live in herds in the arctic tundra during spring and summer months. Both males and females bear antlers. While males lose theirs during spring, females lose their antlers in summer, when giving birth. Their coat color varies according to subspecies, often ranging from brown to gray with white underparts. Their diet includes leaves of aromatic plants, grasses, fungi and lichen. The caribou's main predator is the wolf.
The arctic fox is a nocturnal mammal that can survive temperatures of minus 90 degrees Fahrenheit because of its thick white winter coat, which also is used as camouflage when hunting. Its winter coat is replaced by a thinner blue-gray or gray-brown coat when summer arrives. Small mammals, insects, birds, fish, carrion and berries are part of its diet. Female arctic foxes have litters of up to 14 pups.
The mountain goat or Rocky Mountain goat (Oreamnos americanus) lives in the North American tundra year-round. Mountain goats have a thick white coat and curved horns, which are thicker and more curved in males than in females. With large hooves and strong legs, mountain goats are excellent climbers. Despite their name, mountain goats are not closely related to goats, which are part of the genus Capra.
Part of the family that includes domestic cattle, sheep and bison, the muskox lives in the arctic tundra of northern Canada and western Greenland. Wolves and bears are the animal's main predators. When feeling threatened, the males form a circle around females and their young. Males have a musk gland, which produces a strong smell that attracts females during matting season. Muskox are herbivores, feeding on leaves, moss and lichen.