whales are large, magnificent, intelligent, aquatic mammals. They breathe air through blowhole(s) into lungs (unlike fish who breathe using gills), whales have sleek, streamlined bodies that move easily through the water. They are the only mammals, other than manatees, that live their entire lives in the water and the only mammals that have adapted to life in the open oceans. Like all mammals: Whales breathe air into lungs, Whales have hair (although they have a lot less than land mammals, and have almost none as adults ) Whales are warm-blooded (they maintain a high body temperature) Whales have mammary glands with which they nourish their young, Whales have a four-chambered heart. The biggest whale is the blue whale, which grows to be about 94 feet (29 m) long the height of a 9-story building. Adult blue whales have no predators except man. The smallest whale is the dwarf sperm whale which as an adult is only 8.5 feet (2.6 m) long