Colossal Squid Facts

Description

The colossal squid gets its scientific name, Mesonychoteuthis hamiltoni, from one of its distinguishing features. The name comes from the Greek words mesos (middle), onycho (claw), and teuthis (squid), referring to the sharp hooks on the colossal squid's arms and tentacles. In contrast, the giant squid's tentacles bear suckers with small teeth.

While the giant squid may be longer than the colossal squid, the colossal squid has a longer mantle, a wider body, and more mass than its relative. The size of a colossal squid ranges from 12 to 14 meters (39 to 46 feet) long, weighing up to 750 kilograms (1,650 pounds). This makes the colossal squid the largest invertebrate on Earth!

The colossal squid exhibits abyssal gigantism in respect to its eyes and beak, too. The beak is the largest of any squid, while the eyes may be 30 to 40 centimeters (12 to 16 inches). The squid has the largest eyes of any animal.

Photographs of the colossal squid are rare. Because the creatures live in deep water, their bodies don't do well brought to the surface. Images taken before a squid was removed from water showed an animal with red skin and an inflated mantle. A preserved specimen is displayed at Te Papa Museum in Wellington, New Zealand, but it doesn't convey the coloring or natural size of a living squid.

Distribution

The colossal squid is sometimes called the Antarctic squid because it is found in cold water in the Southern Ocean. Its range extends north of Antarctica to southern South Africa, southern South America, and the southern edge of New Zealand.

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Behavior

Based on capture depths, scientists believe juvenile squid range as deep as 1 kilometer (3,300 feet), while adults go at least as deep as 2.2 kilometers (7,200 feet). Very little is known about what goes on at such depths, so the behavior of the colossal squid remains a mystery.

Colossal squid do not eat whales. Rather, they are a whale's prey. Some sperm whales bear scars that appear to be caused by the hooks of the colossal squid's tentacles, presumably used in defense. When the contents of sperm whale stomachs were examined, 14% of the squid beaks came from the colossal squid. Other animals known to feed on the squid include beaked whales, elephant seals, Patagonian toothfish, albatrosses, and sleeper sharks. However, most of these predators only eat juvenile squid. Beaks from adult squid have only been found in sperm whales and sleeper sharks.

Diet and Feeding Habits

Few scientists or fishermen have observed the colossal squid in its natural habitat. Because of its size, the depth at which it lives, and the form of its body, it is believed the squid is an ambush predator. This means the squid uses its large eyes to watch for prey to swim by and then attacks it using its large beak. The animals have not been observed in groups, so they may be solitary predators.

A study by Remeslo, Yakushev, and Laptikhovsky indicates Antarctic toothfish are part of the colossal squid's diet, as some fish caught by trawlers show characteristic signs of attack by the squid. It likely also feeds on other squid, chaetognaths, and other fish, using bioluminescence to see its prey.

Reproduction

Scientists have yet to observe the process of mating and reproduction of the colossal squid. What is known is that they are sexually dimorphic. Adult females are larger than males and have ovaries that contain thousands of eggs. Males have a penis, although how it is used to fertilize the eggs is unknown. It's possible the colossal squid lays clusters of eggs within a floating gel, like the giant squid. However, it's just as likely the colossal squid's behavior is different.

Conservation

The colossal squid's conservation status is "least concern" at this time. It is ​not endangered, although researchers do not have an estimate of the numbers of squid. It's reasonable to assume pressures on other organisms in the Southern Ocean have an effect on the squid, but the nature and magnitude of any effect is unknown.

Interactions With Humans

Human encounters with the giant squid and the colossal squid are rare. Neither "sea monster" could sink a ship and it's highly improbable such a creature would attempt to pluck a sailor from the deck. Both types of squid prefer the ocean depths. In the case of the colossal squid, a human encounter is made even less likely because the animals live near Antarctica. Since there is evidence that the albatross may feed on juvenile squid, it's possible a "small" colossal squid might be found near the surface. Adults tend not to rise toward the surface because warmer temperatures affect their buoyancy and reduce blood oxygenation.

There is a credible report of World War II survivors from a sunk ship being attacked by a giant squid. According to the report, one member of the party was eaten. If true, the attack was almost certainly from a giant squid and not a colossal squid. Similarly, accounts of squids battling whales and attacking ships refer to the giant squid. It's theorized the squid mistake the shape of the ship for that of a whale. Whether such an attack could occur by a colossal squid in the cold water of Antarctica is anyone's guess.

Sources

• Clarke, M.R. (1980). "Cephalopoda in the diet of sperm whales of the southern hemisphere and their bearing on sperm whale biology". Discovery Reports. 37: 1–324.
• Rosa, Rui & Lopes, Vanessa M. & Guerreiro, Miguel & Bolstad, Kathrin & Xavier, José C. 2017. Biology and ecology of the world's largest invertebrate, the colossal squid (Mesonychoteuthis hamiltoni): a short review. Polar Biology, March 30, 2017.