Dwarf sperm whale modern day whale. Characteristic of sperm whales, the left nostril is markedly larger than the right, and it has a spermaceti organ on its skull. The brain weighs around . The eyes are adapted for low-light environments. The dwarf sperm whale has 14 to 24 teeth, rarely 26, in the lower jaw that are sharp, slightly curved backwards, and–like other sperm whales–lack enamel. The teeth rarely exceed in length, smaller than those of the pygmy sperm whale. At most, 6 teeth are in the upper jaws, though in modern sperm whales, upper teeth are defunct. Unique to "Kogia", there is
Blue whale of its life, a blue whale calf drinks approximately of milk every day. Blue whale calves gain weight quickly, as much as every 24 hours. Even at birth, they weigh up to —the same as a fully grown hippopotamus. Blue whales have proportionally small brains, only about , about 0.007% of its body weight, although with a highly convoluted cerebral cortex. The blue whale penis is the largest penis of any living organism and also set the Guinness World Record as the longest of any animal's. The reported average length varies but is usually mentioned to have an average length