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
Baleen whale the penis, which tapers toward the end, is called the "pars intrapraeputialis" or "terminal cone". The blue whale has the largest penis of any organism on the planet, typically measuring . Accurate measurements of the blue whale are difficult to take because the whale's erect length can only be observed during mating. The penis on a right whale can be up to – the testes, at up to in length, in diameter, and weighing up to , are also the largest of any animal on Earth. All baleen whales use sound for communication and are known to "sing", especially during