Millions of years ago, whales probably walked upon land. As many years passed, the whales changed. Now they live in the ocean.
Whales are mammals, so they feed milk to their babies and breathe air.
They like each other and live in large groups called herds. A baby whale is called a calf. Whales do not have gills, so they cannot breathe under water. They must come up to the surface of the water to get air. The air is breathed in and out through their blowhole, which is on their back.