Almost everyone knows that the blue whale is the biggest animal on Earth. But can we really imagine how big these animals are? A blue whale's length can reach up to 33 meters (110 ft) and it can weight up to 180 metric tonnes (200 short tons). It has a 600-kg (1,320 lb) heart and its tongue weighs around 2.7 tonnes (3 short tons)! That equals about 15 baby elephants!