Blue whales are the largest whales. They are 100 feet long and weigh more than 200 tons. The heart of a blue whale is the size of an automobile, and the tongue weighs about as much as an elephant.
Blue whales grow to their massive sizes on a diet of small shrimp-like animals known as krill. Depending on the time of year, an adult blue whale can consume close to 4 tons of krill a day. The calves of blue whales are also massive. They are born ranking at the top of the world's largest animals. A blue whale is born weighing about 3 tons and measuring more than 25 feet long.