The lemmings and voles are the rats and mice of the Arctic. The lemmings have very short tails. They live underground in summer. Because the top soil freezes in the winter, they cannot burrow underground then, so they live under the snow during the colder months. They eat plants and roots. In a year with plenty of food, millions of lemmings will be roaming the tundra. The owls and foxes have more food than they can eat. They will have more young in years when there are many lemmings. However, the tundra does not have enough food for millions of lemmings. They rush across the tundra looking for food, and are eaten by predators or starve to death. Some try to swim across lakes or rivers and drown. The few that remain continue to have families.