Cetacea of any animal on earth, averaging and in mature males. The brain to body mass ratio in some odontocetes, such as belugas and narwhals, is second only to humans. In some whales, however, it is less than half that of humans: 0.9% versus 2.1%. The sperm whale ("Physeter macrocephalus") is the largest of all toothed predatory animals and possesses the largest brain. The cetacean skeleton is largely made up of cortical bone, which stabilizes the animal in the water. For this reason, the usual terrestrial compact bones, which are finely woven cancellous bone, are replaced with lighter and more elastic
Baleen whale SeaWorld San Diego and, after 14 months, was released because it got too big to take care of. Reaching and , J.J. was the largest creature to be kept in captivity. The Mito Aquarium in Numazu, Shizuoka, Japan, housed three minke whales in the nearby bay enclosed by nets. One survived for three months, another (a calf) survived for two weeks, and another was kept for over a month before breaking through the nets. Baleen whale Baleen whales (systematic name Mysticeti), known earlier as whalebone whales, form a parvorder of the infraorder Cetacea (whales, dolphins and porpoises). They are a