Walruses have long tasks, up to a metre in length. They don't use them to capture prey, however, but to defend themselves against hungry polar bears, or to climb out of the water or over rocks. You can tell the age of a walrus by how light-coloured its skin has become and how long its tusks have grown. A walrus’s skin is 2 to 4 cm thick. Under it, walruses have an 8- to 10-cm-thick layer of fat.