Dolphins are exceptionally friendly, playful and intelligent creatures. They are believed to talk to each other by an elaborate language of clicking sounds. 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.