Seals have a streamlined shape which enables them to swim very fast. But on land, where they breed, they are very slow. Most seals eat fish, squid and krill, but the leopard seal will eat penguins and other seals. Walruses live on beaches near shallow waters at the edge of the polar ice in the Arctic. They live mainly on shellfish.
Deserts are hard places for mammals to live.
They are very dry and often very hot too. But there are mammals well-adapted to these conditions. Kangaroo rats conserve water by eating their own droppings. Lack of shelter can also be a problem for desert mammals, especially as deserts can swing from scorching days to cold nights. Some mammals, like naked mole rats, live underground all the time.