Otters are semi-aquatic, fish-eating mammals. Members of the weasel family, most species of otter live near rivers or ponds, while the sea otter lives in the coastal waters of the Pacific Ocean. Designed for speed in the water, the otter has a long, muscular body, water-repellent fur, webbed paws and a thick, flattened tail. It moves through the water by flexing its body and tail up and down, while paddling and steering with its hind feet. It feeds on other water creatures, including fish, shellfish, amphibians, birds and small mammals. Its stiff whiskers are sensitive to slight movements in the water, helping it to locate its prey.

Giant otter

The giant otter looks similar to other kinds of otter, but it is larger, sometimes reaching 1.8 metres (6 ft) in length. It lives mostly in the Amazon River and other wetlands of South America. Hunted for its fur, the giant otter is now endangered.

The sea otter is one of only a few kinds of animal that uses tools. The otters dive for sea urchins, crabs and shellfish to eat. Then they come to the surface carrying their catch—and a stone—in pouches under each front leg. Floating on their backs and using their bellies as tables, the otters smash the shells open with the stone to reach the soft flesh inside. They also use stones to hack abalone sea snails off rocks.