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
The Brain of Morbius the ruins. Morbius attacks the Doctor, but is knocked out by Solon's tranquilliser. As they carry the creature back to the castle, the Doctor tells Solon that Morbius's brain will be detached and returned to the Time Lords. The body of the dead Sister is brought back to Maren. Ohica reports that witnesses saw a creature and then the Doctor and Solon hunting for it. Maren realises that Solon has succeeded in his experiments and resurrected their ancient enemy. But Maren is too old and weak to leave the shrine, and she gives Ohica permission to lead the Sisters to