Squid and Octopus – can we see eye to eye?

As Squidward Tentacles said to SpongeBob Squarepants, “If I had a dollar for every brain you don’t have, I’d have one dollar.”

Brains aside, what else do squids have that sponges don’t?

Last night I watched a BBC documentary “Giant Squid: Filming the Impossible – Natural World Special” (http://www.bbc.co.uk/programmes/b0377t15) on the giant squid, that elusive creature of the inky deep, famed for suckering onto ships of yore with unfeasibly long tentacles and pulling them under the waves.

Well, who knows, but the scientists shown in the documentary had a fairly hard task to locate a real, live giant squid way more than 800 metres below the surface, which is where they generally live, so I think it would be incredibly rare to see a living specimen waving its spectacular tentacles about at sailors on deck.

Finding the giant squid

They did, however, manage to film some incredible footage of a giant squid by dangling some bait from a line and diving in their special, spherical, glass vessel to an incredible depth below the waves.

I almost had an attack of claustrophobia just watching them. But then I realised that this was just like the GUP vessel commanded by Captain Barnacles in the children’s programme, the Octonauts, and felt much better. Captain Barnacles is always OK.

While we’re on the subject, I also have to comment that, since watching the Octonauts, I have become a lot more knowledgeable about marine life, as it is incredibly well-researched and accurate (apart from the wild anthropomorphism, size and scale, the animated vegetables and the squid with a monocle…er, but my point stands otherwise.) Hurrah for the BBC!


Captain Barnacles and crew

Eye witness

Anywaaaaay…..back to the documentary, the squid hove into sight, attracted by the bait, and was not put off even when a strong light was shone onto it. The most remarkable and surprisingly beautiful aspect of this strange being was that it was shiny and completely golden, something not seen in the dead specimens which was all that had previously been seen by man. It was utterly mesmerising.

It appeared to be similarly mesmerised by the GUP (yes, I know it’s not really called that, but it’s stuck now so just go with me). It wafted about with its huge eye fixed on the camera – or as it felt, on me.

The creature was three metres long, missing, as it was, its two hugely long tentacles and left only with the regular length ones. Its eyeball was the size of a football, with a big, odd pupil.  And then it BLINKED. “Who knows,” breathed David Attenborough “what it is thinking.” Who indeed.

Freshly-caught squid – closeup of eye

Windows to the soul?

I was very disappointed last year, when I visited the Bristol aquarium, to discover that their huge octopus in a tank, the giant pacific octopus named Elsa, had died. I wondered if she had died of loneliness and a broken heart from being squelched into the surprisingly small, now empty tank, but it turns out that they only live for four years or so, broken heart or no.

I was disappointed because I had very much wanted to look into her eyes and try to see what can be found in the eye of a huge cephalopod. Quite a lot, I like to think. Not just eye-wise, but also soul-wise.

People often identify with marine mammals, particularly dolphins, and speak of their high intelligence, social structure, memory, and communication.  I suppose a squelchy thing with tentacles just isn’t quite as touchy feely.  (Or actually it is probably too touchy feely, come to think of it). Nobody pays for a ‘swimming with cephalopods’ experience, do they?

But they are indeed quite intelligent, probably in part due to their predatory ways and the need to find food. In fact, they are by a long way the most intelligent of all invertebrates.

Various species are capable of assorted feats, ranging from climbing on board ships to sneak into the containers of freshly caught crabs for an easy snack, to throwing rocks in an aquarium, and learning how to open a screw-top jar which opened clockwise, containing another screw-top jar which opened anti-clockwise, and retrieving an edible treat from inside this. They pick up coconut shells, carry them off and arrange them strategically to make shelters.


And most amazingly, they can communicate by turning themselves an array of colours to communicate with each other, though it is perhaps the pulsating and flashing patterns rather than the colours themselves which signal the message.

But it doesn’t stop there – the Caribbean Reef Squid can flash out a message to one friend on one side, and use the other side of his body to flash out a different message to another friend on the other side. I was previously quite proud of the fact that I can be typing something out, and continue to do so whilst talking to someone about something else. Now I don’t feel quite so smug. Or dextrous.

Mammal appeal

The fact that the majority of us don’t find cephalopods the most endearing of creatures is probably not merely that their bodies are weird – all squelchy ‘cephalo’ and ‘pod’ and nothing else – it is that we just ‘get’ other vertebrates, and particularly mammals. We think the babies are adorable.

Why do we relate to other mammals so easily? Could it be those BIG eyes that they have, just designed to melt our hearts with their utter cuteness? And don’t forget those long eyelashes. I have never seen a baby squid but I suspect it isn’t very cute. But their eyes are most definitely enormous, so why is this?

Relative differences

Cephalopods have a highly evolved and complex, yet very different nervous system from vertebrates. The last common ancestor of cephalopods and vertebrates existed more than 500 million years ago.

Despite our differences, we crucially all inherited a particular gene  (called Pax6) which allowed us to develop eyes.

Now, you don’t need me to point out that the difference between a squid or octopus’s body and our own, or indeed any vertebrate’s body, is quite pronounced and remarkable, as we evolved into very different things. For a start, their mouths are where their bottoms should probably be and they eat with their heads*.

*I am aware that this may not be pure scientific fact…..

What is fascinating, though, is that their eyes are surprisingly like our own. They contain a lens, which focuses images onto a retina, and that focus can be altered. The middle of the eye is full of liquid, like ours. And while the giant squid has eyes either side of its head for all-round vision, the colossal squid even has them on the front to allow for depth perception.

However there are definite differences. For example we focus using muscles to shape our lens, whereas they move the lens around to focus. We have rods and cones to detect light and colour, while they have a different type of receptor cells and don’t see in colour (or at least see colours as we do).

Overall though, it is still what is called a ‘camera eye’; in other words, an enclosed structure with an iris, a lens, a liquid middle, and a retina to sense the image. Just like ours. In contrast, consider an insect’s compound eye. You just can’t look into it and get anything back, can you?

Put a lid on it

Now, some types of squid, myopsids, have a cornea, which keeps their eyes protected. Others, the oegopsids, do not, so to protect their eyes, say perhaps from a strange GUP full of humans shining a torch in their faces, they have eyelids made of skin and can blink, like the giant squid in our documentary.

That, for me, really made the encounter, and somehow felt almost like a moment of acknowledgement, a confirmation that the lights were on and somebody was definitely at home.

The whole eye and eyelid of this squid, and my own, are a splendid example of convergent evolution. By different paths, we have reached a similar condition. Now, isn’t that what we all look for in a meeting of the minds?

So what else have we converged on?

Do you mind?

In 2012 a group of brainy bigwigs (cognitive neuroscientists, neuropharmacologists, neurophysiologists, neuro-everythings) got together at Cambridge University to talk about consciousness in humans and other animals. They came up with what they called The Cambridge Declaration on Consciousness. This was the fairly obvious assertion that lots of animals, including all mammals and birds, have the neurological capacity for consciousness. But perhaps less obvious was the specific inclusion of octopuses in this category.

While the concept of consciousness is acknowledged, like a cephalopod, to be rather slippery, and its existence in animals we can’t communicate with must be even more slippery, my own, probably non-scientific understanding is that, aside from awareness of self and other, consciousness means having what I would call a ‘mind’ rather than just a brain.

A friend of mine who did get to see Elsa the octopus in the Bristol aquarium, before her demise, told me that she looked into Elsa’s eyes, with their big pupils, and Elsa looked into hers, and she had a great feeling of empathy for the animal.

David Attenborough said it:  who knows what she was thinking?

Whatever it was, it would appear that something about that convergent evolution and the camera eye can tug at the same part of us as the mammalian connection.

I defy you to look into the eyes of a cephalopod and feel nothing.

Of course, the monocle can be a little distracting….


Professor Inkling of The Octonauts

In case you have not guessed, I am definitely not a marine biologist, scientist, or in any way expert, I just enjoy good documentaries, The Octonauts, and wish David Attenborough was my Grandpa, so please excuse any faults or inaccuracies in the above!


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