Whales are aquatic mammals. Whales share five common characteristics with other mammals. As adults, whales rarely have any hair on their bodies. However, a young whale may sport sparse hairs along its rostrum. A whale's smooth skin makes it sleek and fast.
Some people say it feels like a wet innertube.
Whales have lungs and breathe air. A whale breathes air through nostrils called a blowhole, located on top of its head. There are two groups of living whales. Baleen and toothed whales differ in a number of ways, including biology and behavior. Animals commonly called dolphins and porpoises are simply small toothed whales.