Colossal Squid: Your questions answered

Thanks to everyone who sent in questions – our scientists answered as many as they could during the live stream. There were so many great questions we couldn’t answer them all during the event, so as promised, the most frequently asked questions are answered below.

Visit the TONMO forum if you have further questions about the colossal squid. Dr Kat Bolstad and others from Auckland University of Technology’s Lab for Cephalopod Ecology and Systematics will endeavour to answer your questions.

Aaron Boyd Evans counts colossal squid suckers. Photographer: Norm Heke © Te Papa

Aaron Boyd Evans counts colossal squid suckers. Photographer: Norm Heke © Te Papa

Size

The most recent colossal squid specimen is approximately 350kg. The total length is unknown as the tentacles, which can be up to 2 metres in length, were not attached to the animal upon capture.

The colossal squid examined in 2008 weighed 495kg. Once the specimen was defrosted the final total length was determined to be 4.2 metres. It seems that the two tentacles may have shrunk considerably after the squid had died.
See How big is the colossal squid? for more information on size.

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Age and Lifespan

It’s estimated that colossal squid live to be around two years old. It’s possible that they grow from a few millimetres long to over 10 metres, in just two years! Scientists don’t know how old the most recent colossal squid specimen is. Hard parts of the squid, such as the beak, contain indicators of growth, a little bit like tree rings. This will help scientists estimate the age of the specimen.

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Habitat

Colossal squid are found in deep, cold waters of the Southern Ocean.

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Population Size

From examination of animals such as sperm whales, which prey on colossal squid, the species seems to be abundant in the Antarctic, but an exact population size is unknown. About 80% of sperm whale diet (by weight) is made up of colossal squid. A healthy sperm whale will eat between 1 and 1.5 tonnes of food each day – that’s a lot of squid!

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Diet

Colossal squid are known to eat large fish, such as the Patagonian toothfish, but what else makes up their diet is unknown. Scientists from  Auckland University of Technology (AUT) will analyse the stomach contents of the animal to determine what exactly the squid feeds on. This is the first colossal squid specimen to contain stomach contents, so it’s an excellent opportunity to learn more about the animal’s diet.

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Colossal squid beak. Photographer: Norm Heke © Te Papa

Colossal squid beaks can be used to determine the age of the specimen. Photographer: Norm Heke © Te Papa

How long does it take the squid to finish a meal?

It probably takes the colossal squid quite a long time to finish a meal, although scientists don’t know exactly how long. Patagonian toothfish are over 2 metres long, but the colossal squid has to use its beak to cut its prey into tiny pieces. The oesophagus (the tube linking the mouth to the stomach) is only around the size of an adult human thumb, as it has to fit through the middle of the doughnut shaped brain.

Other squid have a strategic, if rather gruesome, tactic to deal with this anatomical conundrum: they deliberately eat through the back of a fish’s neck, to sever the spinal cord and render the prey immobile. This gives the squid plenty of time to eat its dinner.

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Sex

Scientists examined the recent colossal squid and found that it was female, as are all colossal squid specimens found so far. It is unknown if there is a biological reason, such as sexual dimorphism or imbalances in the ratio of females to males, for the lack of male specimens.

Gender was determined by the animal’s anatomy as the specimen had ovaries, which contained eggs. If the specimen was male it would, like other animals that reproduce sexually, have a penis and spermataphoric gland.

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Reproduction

See Biology of the colossal squid for more information about reproduction.

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Colossal squid skin is delicate and tears easily. Photographer: Norm Heke © Te Papa

Colossal squid skin is delicate and tears easily. Photographer: Norm Heke © Te Papa

Skin appearance and colour

Colossal squid skin is gelatinous and delicate, which tears very easily. This is why the skin appears to be peeling. However, it’s in extremely good condition for a specimen of this size, and researchers have taken skin samples to investigate further.

Small pigment-containing cells, called chromatophores, give the skin its reddish-pink colour. Colossal squid can change their skin colour, from pale pink to deep red.

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Examination tank and water

The colossal squid was placed in fresh water to defrost, with gently running water used to ensure an even temperature across the specimen. The water turned brown due to the ink sac and liver releasing ink and lipids (building blocks of fats) into the water. The water probably also contained haemolymph (which is a bit like blood) and ammonium chloride (which squid use for buoyancy).

Scientists did not change the water as this would have caused damage to the fragile specimen.

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Eye

See The Eye of the Colossal Squid for more information about the eye.

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Aaron Boyd Evans counts colossal squid tentacles. Photographer: Norm Heke © Te Papa

Aaron Boyd Evans counts colossal squid tentacles. Photographer: Norm Heke © Te Papa

Hooks, suckers and beak

The hooks and beak are made of chitin, the same as fingernails or cats claws

The powerful suckers could give you a bruise, and a ring-shaped cut. The calcareous ring of teeth is quite sharp.

Each squid species has a beak that is unique in size and shape, which means that beaks can be used to tell species apart. The colossal squid uses powerful muscles to move the beak up and down. A bit like a parrot, the beak has an upper part and lower part, but in squid the lower part overlaps the upper one. The strong, sharp beak slices through prey’s flesh, cutting it into small pieces.

See The beak of the colossal squid for more information.

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Capture

The colossal squid was captured when by the fishing vessel San Aspiring, while the vessel was fishing for Patagonian toothfish in the Ross Sea.

When longlines were being drawn up, a colossal squid attacked a toothfish attached to one of the lines at 1500 metres below the surface. As the longlines were drawn up, the squid hung onto the toothfish and was brought to the surface. Entangled in fishing lines, and attacked by toothfish, the colossal squid was dying when it got to the surface and was unable to be released back into the water. The value of the animal to science was recognised, so it was carefully brought it aboard.

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More colossal squid info

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