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
Whale lungs can hold about 5,000 litres of air. Spout shapes differ among species, which facilitates identification. The heart of a whale weighs about 180–200 kg. It is 640 times bigger than a human heart. The heart of the blue whale is the largest of any animal, and the walls of the arteries in the heart have been described as being "as thick as an iPhone 6 Plus is long". All whales have a thick layer of blubber. In species that live near the poles, the blubber can be as thick as 11 inches. This blubber can help with buoyancy (which