24 Jul 2020

On the Intelligence of Fish

I'm not as dumb as you look ...


I.

I suppose the cognitive ability of mammals and birds is now pretty much an established fact; that is to say, human beings have finally conceded that they are not the only creatures that possess minds and know how to think and use language, etc.

Unfortunately, however, there's still lingering prejudice when it comes to other classes of animal - fish, for example, are still not accorded the respect they deserve and many people continue to subscribe to the belief that they and other acquatic lifeforms are intellectually inferior to terrestrial organisms.

One doesn't have to be an ichthyophile - or even particularly fond of our underwater friends - to be irritated by the injustice of this and the anthropocentric conceit it displays ... 


II.

To say it loud and clear right from the start: fish are not stupid!

In fact, in many areas, such as memory, their cognitive abilities match or exceed those of animals usually ranked above them in the hierarchy of intelligence constructed by man; numerous studies have shown that they can retain information for months or even years - and this includes goldfish!

And whilst they typically have quite small brains (relative to body size), some species have extremely large brains (again, relative to body size) and are capable of learning complex tasks and forming cognitive maps. (There are some people who can barely manage to do this.) 

Of course, having only mouths in which to hold and manipulate objects (no fingers, no hands or feet), severely restricts their use of tools. But some species of fish use shells and rocks in ways that might surprise many and in one recent laboratory study, Atlantic cod were trained to pull a string in order to release food from a feeding machine. Also, let's not ignore the fact that fish can construct sophisticated shelters and nesting places ...

Such behaviour may be innate, rather than learned, but it's still impressive: for we're not just talking holes in the sand here, but deep and extensive excavations reinforced with coral fragments; beautiful-looking pebble mounds and sand towers; nests made from vegetation, glued together with bodily fluids specially secreted for the job and decorated with coloured algae and/or bits of artificial material that now litter their world just like ours. The fact that fish will often make repairs and build extensions (quicker than my next-door-neighbour) further suggests considerable DIY know-how.

Moving on, we come to the question of social intelligence (i.e., the capacity to know themselves and recognise others) ...

It seems that fish can remember things about other individuals; whether they are friend or foe, for example - something that is obviously quite crucial in a world of dog eat dogfish - and this causes them to modify their own behaviour accordingly (including ways that might even be thought of as manipulative and deceptive, though probably it's going a bit far to say they possess a theory of mind).

Although rare, there are instances of fish cooperating with others of their kind; when hunting prey, for example, it often pays to work in groups. And they can communicate amongst themselves using sign language as well as squeaks and other low-frequency sounds, inaudible to the human ear.

Thus, D. H. Lawrence was wrong to describe them as soundless and out of touch. Indeed, they even enjoy gently rubbing their bodies against one another, so are not suspended in watery isolation, forever apart. That said, Lawrence does recognise that fish not only know fear but joie de vivre - and their joy is often expressed in play behaviour; another key indicator of intelligence.

Finally, fish can learn from other fish simply by observing them in action (this is sometimes described as the cultural transmission of knowledge). You might ask what does a fish have to learn? Well, the location of a reliable food source, or a convenient hiding place, would be two examples of things that it might be crucial to have knowledge of. And, if you are a fish who happens to provide a grooming service for another species, it's important to learn how to do a good job.    

So, in sum: fish are intelligent and sensitive animals, with good memories, impressive problem-solving skills, and the ability to learn new things. We should treat them with the same care and respect as we would warm-blooded creatures, even if they are to some extent forever beyond our understanding and even if, as Lawrence says, we will never know their gods.


Notes

Image adapted by Stephen Alexander from a bottle of Albariño by Faustino Rivero Ulecia; a refreshing white wine with a citric finish that makes a perfect accompaniment to, er, fish ... 

See: D. H. Lawrence, 'Fish', in The Poems, Vol I., ed. Christopher Pollnitz, (Cambridge University Press, 2013), pp. 289-94. The poem is very lovely, even if technically incorrect on a number of points; but then, to be fair, Lawrence was a poet and not a marine biologist. It can be read online by clicking here

For a sister post to this one on the intelligence of reptiles, click here


1 comment:

  1. Excellent, important post. Thank you.
    The book to read on this subject is What a Fish Knows, by Jonathan Balcombe.
    Do all you can to end the mass horrific exploitation of fish, please. They are the most murdered animal on the planet. Trillions are killed by insensitive greedy human fools each year. An horrendous massacre.
    And they are tormented by idiotic selfish anglers, in the name of "sport". Lawrence alludes to this cruelty in his great poem, Fish.
    There's now a campaign to end all fishing. Please lend your support.
    Thank you.
    And please DON'T keep fish as pets.
    It sends them mad. And makes them ill.
    Great Lawrence scholar, Keith Sagar, was an authority on tropical fish, who made more money from his books about that than from all his literary criticism. He kept them, in a huge aquarium. But when he left a neighbour to look after them while he was on holiday, the neighbour, without thinking, turned his electric off, and they all died. He never kept them again.

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