Circumpolar around Antarctica and in the Southern Ocean
Open ocean (mesopelagic to bathypelagic)
Class Cephalopoda (squids, octopuses, and relatives), Family Cranchiidae (glass squids)
The colossal squid is a massive squid that lives in the deep sea surrounding Antarctica, and it is the holder of multiple records. Not only is it the largest invertebrate on Earth, it also has the largest eyes of any animal, larger even than those of the great whales. Human knowledge of the colossal squid is based on very few specimens that have been captured in deep-sea fisheries and on beaks that have been found in the stomachs of this species’ most significant predator, the sperm whale. With such limited opportunities for study, it is difficult to characterize the biology and ecology of such a rare species, even one as large as the colossal squid.
Reaching combined body and tentacle lengths up to 46 feet (14 m) and weights of at least 1100 pounds (500 kg), the colossal squid is a very large deep-sea predator. Like in many large species, all the largest individuals are female. They eat small and large fishes (including the Patagonian toothfish) and other squids. Their tentacles are covered with suckers that are equipped with strong, sharp hooks, used in both capturing prey and fighting off predation. Writers have often imagined that this species engages in fierce battles with sperm whales, leaving both species injured. Most southern Sperm Whales are covered with scars from colossal squid hooks. Other diving mammals (including the southern elephant seal) and large Southern Ocean predators feed on juvenile colossal squid, but the sperm whale is the only species known to take adults. Specific mating behaviors are unknown in this species, but it reproduces via internal fertilization.
Colossal squid are only rarely captured in deep-sea fisheries targeting other species. In almost every case, they have been captured trying to feed on hooked fishes rather than in nets. This species is not targeted commercially and is likely naturally rare. In a recent analysis, scientists reported that the colossal squid is a species of least concern. As it is an important prey species for charismatic, protected species like sperm whales and southern elephant seals, it is vital that scientists determine its population trends and continue to study its biology and ecology.