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
Whale shark feeder, targeting concentrations of plankton or fish. It is able to ram filter feed or can gulp in a stationary position. This is in contrast to the passive feeding basking shark, which does not pump water. Instead, it swims to force water across its gills. A juvenile whale shark is estimated to eat 21 kg (46 pounds) of plankton per day. The BBC program "Planet Earth" filmed a whale shark feeding on a school of small fish. The same documentary showed footage of a whale shark timing its arrival to coincide with the mass spawning of fish shoals and feeding