Squid Facts

Squid Profile

For millions of years, the Earth went through an edgy teenage period where it spent a whole period covered in ice.

But almost the second as this ice thawed and the Ediacaran began, ancestral molluscs popped into existence. The marine “Garden of Ediacara” was perhaps the most mysterious, alien-like habitat for life on our planet, and in it, there began a lineage of molluscs that would survive every subsequent mass extinction event and come out of it alive, intelligent, lethal, and ready for the next.

By the end of the Ediacaran or the beginning of the Cambrian, cephalopods were taking over. And today, no animals embody the off-world intelligence and cold, predatory nature of these ancient life forms than the squid.

Squid Facts Overview

Squid are as different from humans as it gets, living, as they do, in habitats inhospitable to our species, using bodies with no bones, and lights instead of sounds to talk to one another. Yet, they have similarities, too: a killing instinct, an intelligence, and the urge to attack people who are making too much noise in their homes.

Interesting Squid Facts

1. They’re ancient

Squids are a superorder – that is, two orders of animals in the cephalopod class. They are members of one of the longest lines of complex life that we know about: the molluscs.

That places them in the same phylum as clams, snails, and the slugs that steal your lettuce. This is the largest marine phylum there is, and has been immensely successful on land, too, becoming second only to the arthropods.  

Squid didn’t diverge from their modern relatives until the Jurassic, but cephalopods before them were remarkably similar. Hooked tentacles, vicious beaks, and enormous eyes, as well as ink sacs, siphons for rocket propulsion, and… shells.

Squid, along with cuttlefishes and octopuses, migrated their shells internally, and what’s left of the ancestral squid shell now makes up a slender bone-like support inside the animal called a pen.

And aside from these constants, there is a wealth of differences to be found within the squids themselves.

2. They’re diverse

Squid come in all sizes and colours, and quite a range of shapes, too. For example, the Oegopsida order contains eerie animals like the bigfin squid, with the body of a deflated balloon and eight metre tentacles, while the other squid order, the Myopsida, contains various species of squid that can flash with different colours.

And then, there’s a third order in which there is a single squid species you can fit on your thumbnail.

3. They can be tiny

The so-called pygmy squid has an entire order to itself. It’s a single species, and the smallest squid known, at around 1.5 cm across. This little plankton feeder comes in various colours and patterns too, and behaves just like many other squid species, only in a much smaller world.

And at the other end of the spectrum are the largest invertebrates on the planet.¹

4. Or enormous

Giant squid are so elusive that they were only photographed for the first time in 2004-ish, and only caught on video a couple of times since then.

They are real-life krakens and inhabit the most inaccessible regions of our planet in the deep oceans. Inaccessible to us, that is – sperm whales notoriously dive down there to eat them.

And they come back up with terrific scars from the hooked suckers – something which is only found in the Oegopsida squids – and something which goes to show just how mean these animals are. Specimens have been washed up that were 14 metres long, and some unconfirmed reports offer 20 metres as the record.

And they hunt down there in the pitch black, with the largest eye in the animal kingdom and a hardened beak that can bite through a fish spine in one. And giant squid are the longest, but colossal squid have them beat by weight. At around 500 kg, these are the heaviest animals with no bones.

And, from what we know about their octopus relatives, their intelligence may well be more frightening still.

5. They’re smart

Now, deep-sea animals live in cold temperatures, and when animals are cold, they’re generally pretty stupid. Think crocodiles, sloths, and Greenland sharks. But not all squids operate at these temperatures.

Some, like the Humboldts, are far hotter. And with heat comes speed, and the chance at having a fast brain, as well. Squid are known to flash at different speeds, likely communicating with information encoded in the frequencies of these flashes, and they can change colour, too. Humboldts flash to show aggression or excitement, and this has been witnessed firsthand by some divers who were lucky to get out of the situation alive.

Most squid species, like octopuses, are solitary, but Humboldts are not only gregarious, but likely social, cooperative hunters. These two-metre squids are the wolves of the ocean, able to solve problems, communicate with light, and even attack divers.

They are aggressive, fast, and dangerous animals, and they’ll eat anything, even their own kind. These animals show us what we might come to learn about other species like them, too.

6. They’re not going anywhere

There are no squid species listed as Endangered on the IUCN Redlist. That’s not to say they’re all doing fine – we barely understand the ones we are most familiar with. But squids as a whole make up between 300 and 400 species, and they have survived extinctions that would have killed us sixty times over.

The most secure are those lurking in the deep. The deepest oceans are a remarkably stable environment that barely fluctuates in salinity and temperature. And so even with the total annihilation of surface-dwelling species, the deep sea will ride it out and be ready to repopulate the shallows once the dust settles.

So, of all life forms on the planet today, squid – or whatever they will evolve into – are possibly the most likely to be here in another half a billion years.

Squid Fact-File Summary

Scientific Classification

1. , “Idiosepiidae”, Wikipedia.