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
Mesoplodont whale what effect this has on the population. Longman's beaked whale ("Indopacetus pacificus", also known as the Indo-Pacific beaked whale or the tropical bottlenose whale) was originally assigned to "Mesoplodon", but Joseph Curtis Moore placed it in its own genus, "Indopacetus", a taxonomic assignment which has been followed by all researchers. Two extinct species of "Mesoplodon" are known, "M. posti" and "M. slangkopi". Mesoplodont whale Mesoplodont whales are fifteen species of toothed whale in the genus Mesoplodon, making it the largest genus in the cetacean order. Two species were described as recently as 1991 (pygmy beaked whale) and 2002 (Perrin's beaked