During certain times of the year, an adult whale eats about 3.6 metric tons of krill a day. The whale swims slowly through the water with its mouth open, and thousands of tiny fish and plankton swim into it. But the whale can't swallow anything larger than a shrimp.
Whales are mammals, and so they cannot stay under water for too long. They need to come to the surface to breathe after 10 to 20 minutes. Blue whales usually dive around 100 meters, but can reach a depth of 500 meters. When they come to the surface, they blow a wet stream 12 to 15 meters up in the air