Little is known about the elusive Colossal Squid (Mesonychoteuthis hamiltoni) due to its remote natural habitat in the deep waters of the ocean. Adult Colossal Squid can descend to a depth of up to 2.2km, while juvenile squid can be found up to 1 km down. The great depth at which the squid live means they are not detectable by undersea camera or other methods of observation. It is thus hard for scientists to confirm much about the life-cycle or ecology of the Colossal Squid as they are reliant for observation on the occasional immature specimen caught by deep sea trawlers.
The global distribution of the Colossal Squid is primarily in the freezing waters surrounding the Antarctic, a vast region known as the Southern Ocean. The squid's preferred habitat of the cold depths of the ocean provides it with a diet of large fish, in particular the Patagonian Toothfish, other squid species and Arrow Worms.
This habitat also leaves the M. hamiltoni vulnerable to falling prey, in turn, to the Sperm Whale and Sleeper Sharks. Other predators such as Beaked Whales and Southern Elephant Seals target only immature squid. Remains of the squid such as beaks and tentacles are, in fact, frequently found within the stomachs of Sperm Whales and provide vital evidence of the species to marine biologists. Sperm Whale have been observed to carry scarring on their backs consistent with injuries inflicted by the hooked tentacles of M. Hamiltoni.
The Squid's known habitat covers a vast yet specific global range, from the southernmost point of South America to the oceanic region beyond the Cape of Good Hope in South Africa, to the southern tip of New Zealand and the Antarctic region. This global spread is concentrated in the southernmost reaches of the earth, touching each continental mass at the lowest point.
Some of the most notable sightings of M. hamiltoni have included the initial identification of the species in 1925, when two tentacles were found inside the stomach of a Sperm Whale. The complete specimen of an immature female was found in 1981 by a Russian trawler in the Ross Sea, off the coast of Antarctica.
The largest recorded specimen of the Colossal Squid was captured by a New Zealand fishing ship in 2007, also in the Ross Sea. The squid was about 4.5 metres long and weighed around 495 kg.
The immature female had been in the process of feeding upon an Antarctic Toothfish which had been captured on a line by the fishing ship. The squid was killed, frozen and taken to New Zealand, where it was defrosted in a bath of salt water.The specimen was put on display in New Zealand's National Museum, The Museum of New Zealand Te Papa Tongarewa.