Colossal Squid - Oceana

Cephalopods, Crustaceans, & Other Shellfish

Colossal Squid

Mesonychoteuthis hamiltoni


Circumpolar around Antarctica and in the Southern Ocean


Open ocean (mesopelagic to bathypelagic)

Feeding Habits

Ambush predator


Class Cephalopoda (squids, octopuses, and relatives), Family Cranchiidae (glass squids)


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.

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Additional Resources:

IUCN Red List