Toothed whale melon consists of fat, and the skull of any such creature containing a melon will have a large depression. The melon size varies between species, the bigger it is, the more dependent they are on it. A beaked whale, for example, has a small bulge sitting on top of its skull, whereas a sperm whale's head is filled mainly with the melon. Bottlenose dolphins have been found to have signature whistles unique to a specific individual. These whistles are used for dolphins to communicate with one another by identifying an individual. It can be seen as the dolphin equivalent of
Whale shark Whale shark The whale shark ("Rhincodon typus") is a slow-moving, filter-feeding carpet shark and the largest known extant fish species. The largest confirmed individual had a length of and a weight of about . The whale shark holds many records for size in the animal kingdom, most notably being by far the largest living nonmammalian vertebrate. It is the sole member of the genus Rhincodon and the only extant member of the family Rhincodontidae which belongs to the subclass Elasmobranchii in the class Chondrichthyes. Before 1984 it was classified as "Rhiniodon" into Rhinodontidae. The whale shark is found in open