Because they live at depths of thousands of meters and rarely surface, the behavior and reproduction of Antarctic giant squid remain a great mystery to researchers.
A simulation of the giant Antarctic 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 more elusive relative: the Antarctic giant squid. The first evidence of the Antarctic giant squid came from tentacles found in the stomach of a sperm whale in 1925. It wasn't until 1981 that researchers captured the first intact Antarctic giant squid, a nearly mature female. This animal's scientific name, Mesonychoteuthis hamiltoni , derives its name from its distinctive sharp, hook-like appendages on its arms and tentacles. In contrast, the giant squid's tentacles have suction cups with small teeth, according to ThoughtCo .
Although giant squids can be longer than the Antarctic giant squid, the latter has a longer mantle, a wider body, and greater mass than its relatives. Antarctic giant squids can measure around 12-14 meters and weigh up to 750 kg, making them the largest invertebrates on Earth. Their enormous size is also evident in their eyes and beaks. The Antarctic giant squid's beak is the largest of all squid species, while its eyes have a diameter of 30-40 cm, the largest in the animal kingdom.
Photographs of Antarctic giant squid are scarce because they live in deep seas and their bodies are not suitable for being brought to the surface. Photographs show that before being brought to the surface, they have red skin and a bulging mantle. One specimen is on display at the Te Papa Museum in Wellington, New Zealand, but it does not show the natural color or size of a living squid.
The Antarctic giant squid is found in the cold waters of the Southern Ocean. Its range extends north of Antarctica and south of South Africa, South America, and New Zealand. Based on fishing depths, scientists have determined that immature squid live at depths of one kilometer, while adults operate at depths of at least 2.2 kilometers. Therefore, the behavior of this species of squid remains a mystery to researchers.
Antarctic giant squid do not prey on whales; instead, they are prey for whales. Some sperm whales have scars, seemingly caused by hooks, on the tentacles of Antarctic giant squid, possibly used for self-defense. When researchers examined the contents of sperm whale stomachs, 14% of the squid beaks came from Antarctic giant squid. Other animals that eat them include beaked whales, elephant seals, Patagonian toothfish, albatrosses, and sleeper sharks. However, most of these predators only eat immature squid. The beaks of adult squid have only been found in the stomachs of sperm whales and sleeper sharks.
Very few scientists or fishermen have ever observed Antarctic giant squid in their natural habitat. Due to their size, depth of habitat, and body shape, researchers believe they are ambush predators, using their large eyes to track prey swimming by, then attacking with their beaks. They have never been seen swimming in schools, so they are likely solitary hunters. Scientists have also never witnessed the mating and reproduction process of Antarctic giant squid. What they do know is that they belong to a group with sexual dimorphism. Adult females are larger than males and have ovaries containing thousands of eggs. It is possible that Antarctic giant squid lay their egg clusters inside a floating gel layer.
Currently, Antarctic giant squid are classified as "least concern" in terms of conservation. They are not endangered, although researchers have not been able to estimate their population. Encounters between humans and the two giant squid species are rare. Neither species can sink ships or attack sailors. They prefer to live at great depths. Adult Antarctic giant squid usually do not surface near the water's surface because warm temperatures affect their buoyancy and reduce oxygen in their blood.
An Khang (According to IFL Science/ThoughtCo )
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