[15][16] Captured in 2007, the largest colossal squid weighed 495 kilograms (1,091 lb),[17] and is now on display at the Museum of New Zealand Te Papa Tongarewa.

[18][19] In 2022-23 there were several attempts made by scientists including an ocean exploration non-profit KOLOSSAL to find and film the colossal squid in its natural habitat for the first time to learn more about its biology and ecological behavior.

[20][21] The science team used a tourism vessel[22][23] to survey 36 locations throughout the Southern Ocean and may have filmed for the first time a small juvenile colossal squid.

[3] Little is known about their behavior, but it is believed to feed on prey such as chaetognatha, large fish such as the Patagonian toothfish, and smaller squid in the deep ocean.

[36] Studies measuring the δ15N content of the chitinous beaks of cephalopods to determine trophic ecology levels have demonstrated that the colossal squid is a top predator that is positively correlated with its increased size.

[37] The colossal squid is thought to have a very slow metabolic rate, needing only around 30 grams (1 oz) of prey daily for an adult with a mass of 500 kilograms (1,100 lb).

[38] Estimates of its energy requirements suggest it is a slow-moving ambush predator, using its large eyes primarily for prey-detection rather than engaging in active hunting.

[43][44] The allowed increase in visual detection strategies, including reduced diffraction blurring and greater contrast distinction, must be extremely beneficial to the colossal squid to justify the large energetic expenses to grow, move, camouflage, and maintain these eyes.

[43] The colossal squid's increased pupil size has been mathematically proven to overcome the visual complications of the pelagic zone (the combination of downwelling daylight, bioluminescence, and light scattering with increasing distance), especially by monitoring larger volumes of water at once and by detecting long-range changes in plankton bioluminescence via the physical disruption of large moving objects (e.g., sperm whales).

[43] The colossal squid's eyes glow in the dark via long, rectangular light-producing photophores located next to the lens on the front of both eyeballs.

[46] It is hypothesized that the colossal squid's eyes can detect predator movement beyond 120 m, which is the upper limit of the sperm whale's sonar range.

[43] Squid have been found to detect the movement of sound waves via organs called statocysts (similar to the human cochlea).

[47] Colossal squid are essentially deaf to high frequencies, such as whale sonar, so they rely largely on visual detection mechanisms to avoid predation.

[14] This species, then named Mesonychoteuthis hamiltoni after E. Hamilton who made the initial discovery, was formally described by Guy Coburn Robson in 1925.

[14] In 1981, a Soviet Russian trawler in the Ross Sea, off the coast of Antarctica, caught a large squid with a total length of over 4 m (13 ft), which was later identified as an immature female of M.

[50] The largest recorded specimen was a female, which are thought to be larger than males, captured in February 2007 by a New Zealand fishing boat in the Ross Sea off Antarctica.

[52] Media reports suggested scientists at the museum were considering using a giant microwave to defrost the squid because thawing it at room temperature would take several days and it would likely begin to decompose on the outside while the core remained frozen.