Colossal squid

The colossal squid (Mesonychoteuthis hamiltoni) is the largest member of its family Cranchiidae, the cockatoo or glass squids, with its second largest member being Megalocranchia fisheri. It is sometimes called the Antarctic cranch squid or giant squid (not to be confused with the giant squid in genus Architeuthis) and is believed to be the largest squid species in terms of mass. It is the only recognized member of the genus Mesonychoteuthis and is known from only a small number of specimens. The species is confirmed to reach a mass of at least 495 kilograms (1,091 lb), though the largest specimens—known only from beaks found in sperm whale stomachs—may perhaps weigh as much as 600–700 kilograms (1,300–1,500 lb), making it the largest known invertebrate. Maximum total length has been estimated between 10 metres (33 ft) and 14 metres (46 ft). The colossal squid has the largest eyes of any known creature ever to exist, with an estimated diameter of 27–30 cm (11–12 in).

The species has similar anatomy to other members of its family, although it is the only member of Cranchiidae to display hooks on its arms and tentacles. It is known to inhabit the circumantarctic Southern Ocean. It is presumed to be an ambush predator, and is a major prey of the sperm whale.

The first specimens were discovered and described in 1925. In 1981, an adult specimen was discovered, and in 2003 a second specimen was collected. Captured in 2007, the largest colossal squid weighed 495 kilograms (1,091 lb), and is now on display at the Museum of New Zealand Te Papa Tongarewa.