But wolves are their main enemy. Groups of wolves often follow a herd of caribou waiting to catch a calf, or a sick or old member of the herd. When wolves eat caribou, they are actually helping them. Caribou have a special part in their stomach where they can store food. Caribou are really fast, they are so fast that they can run 40 miles per hour.
Caribou are excellent swimmers because of their fur.
Their fur is filled with air so it is like a life jacket.