The mystery of the Antarctic giant squid

Because they live at depths of thousands of meters and rarely surface, the behavior and reproduction of the Antarctic giant squid is still a big mystery to researchers.

Simulated Antarctic giant squid living in the deep sea. (Video: Te Papa Museum)

While the giant squid is a monster in terms of size, it has an even larger and less visible relative in the Antarctic giant squid . The first evidence of Antarctic giant squid came from tentacles found in the stomach of a sperm whale in 1925. It was not until 1981 that researchers captured the first intact Antarctic giant squid, a the one about to mature. This animal has the scientific name Mesonychoteuthis hamiltoni , derived from its characteristic sharp hooks on its arms and tentacles. In contrast, giant squid tentacles have suction cups with small teeth, according to ThoughtCo .

Although giant squids may be longer than Antarctic giant squids, the latter species have longer coats, wider bodies, and greater mass than their relatives. The size of the Antarctic giant squid is about 12 - 14m, weighing up to 750kg. This makes them the largest invertebrates on Earth . Their oversized size is also reflected in their eyes and beak. The Antarctic giant squid's beak is the largest of all squids, and its eyes are 30 - 40 cm in diameter, the largest in the animal kingdom.

Photos of Antarctic giant squid are very few because they live in deep seas and their bodies are not suitable for being brought to the surface. Photos show that before being brought out of the water, they had red skin and bulging coats. A specimen on display at the Te Papa museum in Wellington, New Zealand, but does not show the natural color or size of living squid.

Very few people have observed the Antarctic giant squid in their natural habitat.

Antarctic giant squid is found in the cold waters of the Southern Ocean. Their range extends to northern Antarctica and southern South Africa, South America and New Zealand. Based on the depth of capture, scientists determined that juvenile squid live at a depth of one kilometer while adults are active at a depth of at least 2.2 km. Therefore, the behavior of this squid is still a mystery to researchers.

Antarctic giant squid do not eat whales, instead they prey on whales . Some species of sperm whales have scars that appear to have been caused by fishing hooks in giant Antarctic squid tentacles, which may be used for self-defense. When researchers examined the contents of sperm whale stomachs, 14% of squid beaks came from Antarctic giant squid. Other animals that eat them include beaked whales, elephant seals, Patagonian toothfish, albatross, and sleeper sharks. However, the majority of these predators only eat juvenile squid. Adult squid beaks have only been discovered in the bellies of sperm whales and sleeper sharks.

Few scientists or fishermen have ever observed the Antarctic giant squid in their natural habitat. Due to their size, depth, and body shape, researchers believe they are ambush predators, using large eyes to watch prey swim by, then attack with their beaks. They have not been seen swimming in groups, so they may be solitary hunters. Scientists have also not witnessed the mating and reproduction process of Antarctic giant squid. What they do know is that they are sexually dimorphic . Adult female squid are larger than males and have ovaries containing thousands of eggs. It is possible that the Antarctic giant squid lays eggs inside the floating gel layer.

Currently, the Antarctic giant squid belongs to the group of "least concern" in terms of conservation. They are not an endangered species, although researchers cannot estimate the number of squid. Clashes between humans and the two giant squid species are very rare. Both species cannot sink ships and attack sailors. They like to live at great depths. Adult Antarctic giant squids usually do not come close to the surface of the water because warm temperatures affect their buoyancy and reduce oxygen in their blood.