Summarizing the Main Idea pt. 2

Whales are the biggest creatures that have ever lived on the earth. They are even bigger than the biggest dinosaurs were. Scientists think that whales once walked on land. They believe this because whales are not fish—they are mammals

Not only are whales the biggest creatures on earth, they also are some of the smartest. They live in family groups. They communicate with each other, and hunt for food in groups. Mother whales keep their babies close by, and give them gentle taps to guide them in the right direction. Sometimes a whale will lift its head out of the water just to take a look around.

Because whales are mammals, they must breathe air. They breathe through a blowhole on their back. However, they can hold their breath for a very long time. Some kinds of whales can hold their breath for two hours at a time. Whales never really sleep. Instead, they swim along with their blowhole above the water.

Many kinds of whales migrate to warmer waters during the winter months. During the summer, they build up a layer of fat so that during migration they do not have to eat. Bears also eat during the summer to build up a layer of fat so that they can sleep during the winter. Some scientists think the prehistoric whales may have looked like gigantic bears.