Cuttlefish that live more than 10 meters in length live in the ocean. Strangely enough, hardly anything is known about these giants. Three things we don't know about the giant squid and the colossal squid, the largest molluscs in the world.

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1. The size

Exploring the seas around Antarctica made it clear that there is an even bigger squid than the giant squid. "The colossal squid is the largest mollusk on earth. By weight. Think of an animal of 10 meters and more than 500 kilos," says marine biologist Bram Couperus of Wageningen University. However, the colossal squid is probably a bit shorter than the giant squid.

How long do the animals get? It is not known exactly. Large specimens of the giant squid reach up to 13 meters. Or more? Less? It is difficult to measure. The body of a squid can be divided into a head and a mantle, explains Couperus. "The mantle of an octopus is a spherical bag. In the case of a squid, the mantle has an arrow shape." Giant squid's head plus mantle can be 2.5 meters long.

The rest of its length takes a squid from its long arms, especially from two extra tentacles that the animals have for hunting. How long are they exactly? Biologists disagree. Outside the water, on the table in the lab, molluscs are even more elastic, making them look longer. Does the avid researcher who comes to 14 meters not pull the legs too hard when measuring?

2. Their menu

In addition to eight arms, squids also have two tentacles. With that they hunt. "With the giant squid, there are suction cups on the tentacles," says Couperus. The animal fires its tentacles at its prey and grabs its meal with its suction cups. Or so we think. No one has ever seen it happen, because giant squids live thousands of feet deep.

His cousin, the colossal squid, has an extra feature on his catching arms: there are hooks and suction cups on the tentacles. What do the animals eat? "Especially fish. And they cannibalize too," Couperus adds. "Smaller species have been found in the stomach of giant squids."

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Giant squid filmed in Japan

3. The movements of the colossal squid

Marine biologists have been able to film giant squids several times. "They are remarkably mobile," says Couperus.

That cannot be said of its relative around the South Pole. "The colossal squid has been calculated to have very low metabolism." That is the speed at which the animal consumes energy. "It would be enough for thirty grams of food a day. We assume that the animal is very still to waste little energy. If a prey comes along, it opens the attack. "

4. Their final resting place

We owe a lot of knowledge about giant squids to sperm whales. These huge whales dive thousands of feet in search of food. They sometimes have strange round scars around their mouths. That's because sperm whales have giant squid on the menu. They are the prints of vicious suction cups.

How a sperm whale catches a squid? Again no one has ever seen it, but the welts in the skin of the sperm whales indicate that their prey is a nice death-war.

The stomach contents of sperm whales can teach us about its prey. In addition to semi-decayed soft tissues, biologists in sperm whales' stomachs find the hard mouth of giant squids. The beak-like beak is not digested. By measuring the beak of complete squids that float on the beach or in the sea, biologists can check the ratio 'mouth to height'.

And even bigger beaks have been found in sperm whales. This may mean that the largest giant squids are longer than 14 meters. In addition, biologists from the University of St Andrews (Scotland) point out that relationships in molluscs are insidious. In a human of 1.70 meters, the arms can be longer or shorter.

It's even worse with squid. The researchers calculated that a squid with a length of 2.8 meters can be 5.8 meters long in total, but 27.5 meters is also an option.

And perhaps the largest giant squids are even bigger. Perhaps one of the reasons the animals are so out of control is that bigger automatically means harder to catch. The largest giant squids may be so large that sperm whales cannot catch them at all. Then their mouth does not end up in a sperm whale stomach either.

Do you know the difference between mythical creatures and real animals?