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Imagine you’re walking along a rocky beach when, out of the blue, you see this forearm-length
fish charge straight into the shallows.
We’re talking water that’s less than 10 centimeters deep — where a fish /that/ big
could easily end up beached.
After a moment, the animal kind of flops its way back into deeper water.
Then, it does it all over again.
And this is exactly what fish researchers saw off the coast of Saudi Arabia in May 2018.
So they started recording.
And it turns out it wasn’t just any old fish — it was a titan triggerfish, a voracious
and smart marine hunter.
And what they had witnessed was the animal flexing its brain power to snag crabs from
the shore.
Venturing into very shallow water might seem like a poor choice for any fish.
But that triggerfish was no fool.
It had spotten a tasty treat just out of its reach.
So, it figured out how to reach it.
Which might sound pretty clever, because it is.
And it’s right in line with what ichthyologists know about triggerfishes.
For example, in the 1970s, German biologist Hans Fricke tested the problem-solving abilities
of three yellow-spotted triggerfish he decided to call Odonus, Flip and Berta.
He showed Odonus a delicious sea urchin, then put it in a glass dish under an opaque lid.
It didn’t take the fish long to suss out the new materials and solve the problem to
reach the treat.
So, Fricke stepped up the difficulty: this time, the urchin went under a mesh container
that had to be lifted or tipped.
Then, he let Flip and Berta have a go at it.
Once again, the fish got their rewards — but each solved the problem slightly differently!
And they remembered what they learned.
When he moved the set up to a new area and re-tried the test, they both reached the urchin
much faster.
To Ficke, that indicated they were smart enough to generalize their knowledge to new scenarios.
On other dives, Ficke observed what appeared to be evidence for social learning in a different
triggerfish species; in other words, the fish seemed to learn from one another.
He came across five different individuals in a small area that all ate urchins in a
totally unique way.
Instead of flipping them over with jets of water like most triggerfish, they first bit
off the spines — then hauled the urchins up towards the surface so they could nibble
at the soft undersides as the denuded animals fell.
It seemed unlikely that each of them figured this out separately.
So, he concluded it was probably one fish’s idea — then, the other four watched and
/copied/ the behavior.
Now, the researchers aren’t sure if the beaching triggerfish they saw figured out
its clever hunting tactic all by itself, or learned it from another fish.
But no one has reported anything like it in any triggerfish species.
And either way, it shows that the titan has some pretty impressive smarts.
That may be because it’s got a big brain.
See, the part of the fish brain called the telencephalon is relatively large in triggerfishes.
And studies have linked larger telencephalons with better problem-solving abilities, at
least in some species.
Researchers have even suggested that if we really want to understand how cognitive abilities
evolve, we should study fish instead of quote “smarter” animals like primates.
That’s because fish are much more varied in their abilities, environments, and social
interactions than primates are.
So the clever tricks of triggerfish aren’t just cool to watch; they could help teach
us a lot about how intelligence evolves.
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