WHALE
			Phylum: Class: Order: Family: Chordata Mammalia Cetacea Balenidae

Whales are aquatic mammals. They evolved over 100 million years ago from land mammals, and their nearest living relatives are the ungulates, or hoofed mammals. Instead of hair, they have a thick insulating layer of blubber beneath their skin to keep them warm in the cold waters they live in.

The whale's skeleton has traces of hind limbs, relics of its distant ancestry. The front limbs have become flippers, used mainly for balance and steering, while the power for swimming comes from the broad-fluked tail. The nostrils have migrated to the top of the head where they form the blowhole. After a dive, a whale "spouts" to expel the used air from its lungs before taking another breath.

Whales have been able to grow to great sizes, far larger than any living land animal, because the water supports the weight of their bodies. Yet, contrary to popular belief, and despite their vast size, most whales are inoffensive creatures. The largest eat only tiny creatures, some 2 inches (5 cm) long, called krill.

There are two main groups of whales: the whale bone, or baleen whales, which includes the blue, humpback, right, and rorqual whales. The second are the toothed whales, which includes the killer/orca, sperm whales, dolphins, narwhals, and porpoises, which feed mostly on fish and squid.

The killer is the most ferocious of all whales. It preys on seals, penguins, and other whales. The baleen whales eat only krill. Instead of teeth, they have two sets of whale bone, or baleen plates, which are made from modified hair. The whales use these plates as sieves to catch the krill on which they feed.