Fourth Grade
Worksheets
Gray Whale Migration
You probably know that many birds migrate each year. In the spring, they fly north. There they lay eggs and raise their young. In the fall, they fly south to warmer places where they will be able to find more food. But did you know that whales migrate, too?
Gray whales migrate farther than any other mammal. Yes, even though whales live in the ocean, they are mammals. They are not fish. Mammals give birth to babies that look like their parents, only smaller. Mother whales, like all other mammals, feed their babies with milk from their bodies.
Gray whales spend their summers in the cold waters around the North Pole. There they find their favorite foods- small shrimp-like animals that live on the bottom of the ocean called amphipods.
Gray whales are the only whales that eat from the bottom of the sea. They scoop up mouthfuls of mud. Gray whales don't have teeth. Instead, they have long strips of material like your fingernails called baleen. The baleen filters out the food. The whale uses its tongue to push out water. Gray whales also eat clams, worms, and krill. But in the fall, they must migrate.
In winter, the Arctic Ocean freezes. Ships have been frozen in the ice there and must wait until the spring thaw to get free. Whales would die if they stayed there. So in October, they begin their 5,000 mile journey.
