Sperm whale of the Society for Marine Mammalogy, the largest international association of marine mammal scientists in the world, officially uses "Physeter macrocephalus" when publishing their definitive list of marine mammal species. The sperm whale is the largest toothed whale, with adult males measuring up to long and weighing up to . By contrast, the second largest toothed whale (Baird's Beaked Whale) measures and weighs up to . The Nantucket Whaling Museum has a -long jawbone. The museum claims that this individual was long; the whale that sank the "Essex" (one of the incidents behind "Moby-Dick") was claimed to be . A
Bowhead whale organ provides a mechanism of cooling for the whale (which is normally protected from the cold Arctic waters by or more of fat). During physical exertion, the whale must cool itself to prevent hyperthermia (and ultimately brain damage). It is believed that this organ becomes engorged with blood, causing the whale to open its mouth to allow cold seawater to flow over the organ, thus cooling the blood. Bowhead whales are not social animals, typically travelling alone or in small pods of up to 6. They are able to dive and remain submerged underwater for up to an hour. The