There have been legends among sea voyagers and sailors about fierce and terrible giants- monsters capable of attacking ships and dragging sailors to the depths to devour them from ancient times. The legends were confirmed: the colossal squid, known to be the largest invertebrate on the planet, has the power and strength to go toe-to-toe with a whale.

The colossal squid is genuinely enormous, monstrous even. It owns the biggest eye among all animals on the planet, with a diameter larger than a ball. If it inhabited the shallow, warm waters instead of living in the deep waters of Antarctica, the colossal squid would make sharks look like child’s play.

Table of Contents

Quick Facts about Colossal Squid

Colossal squid
Colossal squid | Image Credit – Wikimedia Commons
Scientific NameMesonychoteuthis hamiltoni
HabitatAntarctic and Arctic Oceans
Prey onFish, Squid
ThreatSperm Whale
Distinctive FeatureMassive body size and largest eyes
Weight500-750 kg
Length14 meters
Shape of BrainDoughnut
IUCN Conservation statusLeast Concern

Discovery of Colossal Squid

Image of colossal squid in New Zealand
Image of colossal squid in New Zealand | Image Credit – Museum of New Zealand

The researchers first identified the colossal squid in 1925. They found its arms in the stomach of a dead sperm whale. Not until 1981 first whole creature was captured alive in a net. The largest of all those captured was recorded in 2007 in New Zealand and weighed almost half a ton.

The San Aspiring, a New Zealand fishing vessel, caught the colossal squid in February 2007. The crew was fishing with baited hooks and unexpectedly caught a 500 kg colossal squid nibbling on an Antarctic toothfish to death. They captured the squid and took it to the ship’s freezer as a sample. It is currently exhibited in the Te Papa Tongarewa museum.

There seems to be much respect from both fishermen and researchers regarding the colossal squid. It remains one of the most mysterious squid species to date for man.

Perimeter making the Colossal Squid the scariest Creature

Also referred to as Antarctic squid, an investigation has certified that colossal squid is not fearsome and scariest creatures as we perceive. They are not even aggressive or fast; however, the ancient legends of enormous sea creatures with giant tentacles devouring ships and crew have made these creatures fearsome and scariest for us.

Apart from the legends, their massive size has also made them the scariest creatures. The following features of the colossal squid are enough to confirm how much scarier they are for us.

1. Gigantic Size

The colossal squid is a mollusk belonging to the family of Cranchiidae. It is an animal with a total length of up to 14 meters and a maximum weight of 750 kilograms. This species, like all squids, has eight arms and two tentacles located in the contour of the mouth opening. Both structures differ in various aspects. 

First of all, the arms measure up to 1.15 meters and have suction cups and non-rotating hooks. The tentacles are approximately 2.1 meters long and have between 22 and 25 hooks that can rotate 360 degrees. The two prehensile tentacles help to hold the prey. However, the colossal male squid uses its arms to support the female while they copulate.

2. Largest Eyes

Dr Kat Bolstad holding the lens from a colossal squid eye
Dr. Kat Bolstad holding the lens from a colossal squid eye | Image Credit – Norm Heke

Colossal squids have the largest recorded eyes in the entire animal kingdom, with diameters reaching up to 27 cm. In 2008, Scientist Dan Nilsson of Lund University in Sweden was present at the only dissection of a colossal squid.

There, the scientist examined and handled the eyes – particularly the complex parts of the lens. “At first, we were surprised because there were no other eyes in the same size range. You can find eyes up to the size of an orange in the sea, like those of the great swordfish.” Professor Nilsson told BBC News.

The researchers suggest this may have given the species an evolutionary advantage. It could be related to a greater ability to detect large predators, such as the sperm whale, instead of facilitating prey identification from long distances. The researchers have extensively studied the visual range of this species. The enormous eyes capture the tiny light sources coming from the bioluminescent plankton. 

These lights are activated when the sperm whale dives to hunt. Thus, the colossal squid gets enough time to escape from its predator. “It is predation by large toothed whales that have driven the evolution of gigantism in the eyes of these squids,” said Sonke Johnsen, a biologist at Duke University in Durham, US, who was also part of the study of the research team. The eyes of the same size could have allowed ichthyosaurs, giant marine reptiles that disappeared approximately 90 million years ago, to avoid attacks by even larger fearsome pliosaurs.

Apart from the size, the eyes of the colossal squid also have larger pupils measuring around 80-90 mm across. The huge pupils absorb 144 times more light than those of a human. The importance of vision is also supported by the large size of the optic lobe of these squids, much larger, also proportionally, than the corresponding part of the human brain.

3. Bioluminescence Eyes

These squids have photophores, light-emitting organs elongated in shape and located on each eye’s ventral surface. These structures are composed of specialized mitochondrial cells called photocytes. The photocytes have particular crystalloid characteristics in this squid, with profiles resembling needles. 

In addition, reflective platelets are rare and associated with a microtubular matrix, which gives the borders a comb-like appearance. Photophores can be used in multiple ways, depending on the animal’s needs. Thus, it could be a misleading technique since when the colossal squid is illuminated, the other predators may not consider it a threat. It allows it to get close to and hunt down prey.

4. Fearsome Arsenal Weapons

The colossal squid derives its scientific name, Mesonychoteuthis hamiltoni, because of its distinguishing characteristics. The name derives from the Greek words mesos (middle), onycho (claw), and teuthis (squid), referring to the sharp hooks on the arms and tentacles of the colossal squid.

Thus, it is specially equipped with a fearsome arsenal of weapons, including rotating barbed hooks. The large, powerful fins are about five feet in diameter and make the squid a dangerous predator. It is the only member of the Cranchiidae family with two rows of large hooks in the central part of its arms, thus replacing the suckers, which appear in the proximal and distal parts and are provided with small teeth.

In the final half of the pair of tentacles appears an exclusive and surprising feature: it has two rows of hooks, slightly smaller than those of the arms, which can rotate 360 degrees. These rows are flanked by a row of tiny suckers on each side that help manipulates and hold prey.

Each of the squid’s eight arms has 20 suckers near the beak, 16 hooks further down the arm, and about 150 suckers near the tip. Confident with these weapons, the squid goes toe to toe with the whale, not backing down from a fight. 

Intermittent washing off of carcasses of sperm whales on the shores often depicted scars on their bodies that indicate they regularly do battle with colossal squid, at least in the southern hemisphere waters where they live. And the colossal squid beaks found in the stomachs of sperm whales indicate that the latter usually wins.

5. Ambush Hunting

The squid uses its large and sensitive eyes aided by the supraocular photophores to search for prey. When it finds one, it quickly launches itself propelled by its large fins, launches its tentacles, and grabs it tightly with its rotating hooks. It subsequently wraps it with its arms to finely shred it with its beak. Once held, it is almost impossible for the prey to escape.

The squid fillets the fish with its beak, eating the meat from one side. “Much worse for the fish is the squid start eating at the tail,” said Kathrin Bolstad, associate professor at Auckland University of Technology. When the anglers in New Zealand caught the squid, it was eating a 6.5-foot-long Patagonian toothfish.

6. Deepest Habitat

In the colder waters, the colossal squid is found; throughout Antarctica, New Zealand, and even parts of Africa. Its habitat is so difficult that it hinders its observation. It tends to live in the deepest regions of these areas, more than 1,000 meters below the surface.

Because it lives in the vast depths of oceans, it remained a mysterious and scarier creature for a long time. Even with advanced technology, it is difficult to observe its natural behaviors. Small and juvenile squids tend to be closer to the surface, making tracking easier.

Conservation Status

The IUCN has categorized the colossal squid as a species of least concern. Although the risk of disappearing is low, several factors threaten the populations of this cephalopod. Thus, occasionally, the colossal squid is caught incidentally. In addition, as a marine animal, its development can be affected by water pollution. It leads to the degradation of its natural habitat and the premature death of some species.

Concerning conservation actions, there are no concrete measures. The protectionist organisms suggest carrying out investigative works where this cephalopod’s distribution, ecology, and life history are studied.


The colossal squid has always been one of the ancestral animals of those stories of sailors with more legends than truth. The pirates feared it, the buccaneers respected it, and the sailors dreamed of capturing it. However, the researchers and investigations have led to the fact that they are not fiction but a reality covered with a veil of mystery.

(Last Updated on May 23, 2022 by Sadrish Dabadi)

Ankur Pradhan holds a bachelor’s degree in education and health and three years of content writing experience. Addicted to online creative writing, she puts some of what she feels inside her stormy heart on paper. She loves nature, so she is trying to motivate people to switch to alternative energy sources through her articles.