Cephalopod Intelligence: Actually Not That Dry

In his astonishing debut blog, Boris digs down into the nitty gritty details of cephalopod intelligence – a topic I’m sure is on everyone’s mind. To learn more about the adaptations of squids and octopuses, their prehistoric origins, and what the heck a cephalopod even is, read on Macduff. Whether you’re a complete biology novice or Sir David Attenborough himself, you are sure to find something fascinating in this post.

28th June 2021 (Tau Day!)

By Boris

In the animal kingdom, certain species exhibit extraordinary abilities; from the tardigrade’s ability to survive many extreme conditions to the pistol shrimp’s method of stunning prey with 210 decibel weaponised bubbles. Also, Keep your eyes peeled for a blog on tardigrades!

Invertebrates vs. Vertebrates

But, in regard to intelligence, the vertebrates reign supreme. The humans, great whales, corvids – don’t confuse with a certain pesky virus – and even the manta ray all show prowess in the skills which make up ‘intelligence’; be it memory, problem solving, tool use or a high level of sentience.

Cephalopod - The Manta Ray
Manta Ray

The Manta Ray (Left) has the largest brain of any fish, explaining its ability to recognise itself in mirrors, a feat few animals can perform.

Despite the vertebrate’s general superiority in the intelligence department, one group of invertebrates has bucked the trend. 

The Cephalopod: A Dark Horse

#1 The Mimic Octopus

Cephalopod - The Mimic Octopus
The Mimic Octopus

The cephalopods (squid, octopuses, cuttlefish and the nautilus) all exhibit unparalleled intelligence in the invertebrate world. The Mimic Octopus (Right) copies the behaviour of flounders, jellyfish and lionfish to ward off predators.

#2 The Broadclub Cuttlefish

Conversely, the Broadclub Cuttlefish is able to rapidly change the colour and patterns on its skin to transfix and hypnotise its prey.

Cephalopod - The Broadclub Cuttlefish
The Broadclub Cuttlefish

The application of intelligence to escape predation or catch prey is unimpressive when compared to the quasi-human behaviours of some cephalopods. 

#3 The Humboldt Squid

Cephalopod - The Humboldt Squid
The Humboldt Squid

The Humboldt Squid, an aggressive pack hunter, has been seen communicating with members of its own species by showing certain patterns and colours on its skin, expressing emotions of anger, fear or the desire to mate. These predators can grow to two metres and there are tales of their attacks on humans.

#4 The Common Octopus

Cephalopod - The Common Octpus
The Common Octopus

The Common Octopus, which I am sure has made its way onto many of your plates, is capable of fun. Scientists have seen them pushing objects towards currents, catching said object and repeating this process. The capability and need to keep one’s mind occupied is a significant marker of high intelligence, few animals have shown this characteristic to this extent, especially not invertebrates.

#5 The Blanket Octopus

The Blanket Octopus can use tools like the torn-off tentacles of the Portuguese Man-Of-War. The octopus grasps the base of the tentacle, devoid of stinging cells, and presents the venomous section to potential predators. In addition, the Blanket Octopus is extremely sexually dimorphic, with females of the species getting to 2 metres, and males barely reaching 2.4 centimetres.

Cephalopod - The Blanket Octopus

Cephalopod Brain Structure

The science behind cephalopod intelligence is complex as the structure of their brains is incomparable to vertebrate brains. Firstly, a majority of the neurones present in a cephalopod are not clustered in a brain. Instead, they are spread out amongst their eight arms.

These neurones, while still connected to the brain, are relatively independent. This allows the arms to perform complicated tasks on reflex, without any hinderance to the central brain.

Secondly, the structure of the cephalopod brain is downright alien. The optical lobes of the brain are enormous compared to the rest of the brain, the squid’s axon-controlling muscle contractions in the body are so large they visible to the naked eye. What’s more, the oesophagus passes right through the middle of the brain.

Why is the Cephalopod brain so smart?

But why? What is the use of these smarts? Why did these creatures ditch their hard shells and exchange them for big brains and camouflage?

As Molluscs, cephalopods are soft bodied, much like their relatives slugs and snails. And just like snails, cephalopods once possessed a hard shell, allowing them to protect their soft interior. They were also able to fill chambers in their shell with gas to give them buoyancy.

Where did the Cephalopod saga all begin?

Cephalopod - Pre-historic Octopus

Then, their predators adapted stronger jaws and rounded teeth to crush these shells, leaving the cephalopods and their predators in an evolutionary arms race, 470 million years ago.

Through gradual mutation and subsequent natural selection, some cephalopods internalised their shells and diminished their size, allowing them to provide structure but removing any gas chambers.

Without these shells, the cephalopods became Coleoids. The Coleoids diversified as they could now explore deeper waters and move much faster. The groups that survived are the octopuses, squid and cuttlefish.

In my opinion, it was their increased intelligence, which had to evolve due to their lack of a shell, which enabled them to compete and make it into modern day.

In Summary

Cephalopods are bloody clever. The EU (the Brussels tentacles themselves) passed a law in 2010, prohibiting the scientific testing on cephalopods without anaesthetic. Moreover, Peter Godfrey-Smith’s book Other Minds has brought the subject of their brains and psychology tomany humans, and I would strongly urge you dear readers to give it a read. 

Thank you for soldiering on to the bitter end. If you liked this blog, please get in touch via our instagram  or email and let me know what you think.

Keep a close eye out for upcoming blogs including What Are Tardigrades?

I’ve been Boris – tarrah!


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1 Comment

  1. Gavriel Sacks

    Happy late Cephalopod Week! Absolutely love this debut

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