Whale 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 the more dependent they are of it. A beaked whale for example has a small bulge sitting on top of its skull, whereas a sperm whale's head is filled up mainly with the melon. The whale eye is relatively small for its size, yet they do retain a good degree of eyesight. As well as this, the eyes of a whale are placed on the sides of its head, so their vision consists of two
Mammal at approximately the ⅔ or ¾ exponent of the body mass. Comparison of a particular animal's brain size with the expected brain size based on such allometric analysis provides an [[encephalization quotient|encephalisation quotient]] that can be used as another indication of animal intelligence. [[Sperm whale]]s have the largest brain mass of any animal on earth, averaging and in mature males. [[Self-awareness]] appears to be a sign of abstract thinking. Self-awareness, although not well-defined, is believed to be a precursor to more advanced processes such as [[metacognition|metacognitive reasoning]]. The traditional method for measuring this is the [[mirror test]], which determines if