Big Blue, King of the seas
The biggest living animal in the world is the blue whale. It weighs about 150 tons, the same as 40 three buses one behind the other. Just the whale's tongue weighs 3.8 tons, and its heart is about 450 kilograms. A baby blue whale weighs more than 3 tons when it is born, and gains 90 kilos a day during its first year.