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Yesterday, we looked at the way the intelligence of birds — developed along different neurological paths from that of mammals — is gradually being recognized. At JStor Daily, Matthew Wills, introducing a recent paper, tells us that reptiles too are are smarter than we used to think.

One reason that biologists used to think that reptiles are of uniformly low intelligence was a misunderstanding about their behavior in captivity:

Herpetologist Gilles De Meester and evolutionary ecologist Simon Baeckens write that, into the 1970s, researchers were dismissing reptiles as “reflex machines,” “intellectual dwarfs,” and creatures of “very small brain.” The latter description implies much—but those implications turn out to tell us more about researchers than the subjects of their studies.

The few earlier studies that seemed to confirm the dumb reptile stereotype had “inadequate and ecologically irrelevant experimental study designs, such as suboptimal room temperatures or insufficient reinforces,” write De Meester and Baeckens. For instance, food, which works well as a motivation for rodents and birds in cognitive tests, seems to have much less appeal to reptiles because of their low metabolic rate and irregular feeding habits. Snakes, as an example, may not want to eat for months after consuming large prey, so a new food source may not interest them at all.

“The Reptilian Renaissance,” April 11, 2025

It turns out that reptiles observed in the wild can be rather clever:

There’s even some evidence of reptilian tool-use: species of crocodiles and alligators “display sticks and twigs on their snout in order to lure nest-building birds.” This has only been observed in bird-breeding season, when the birds on the lookout for sticks to construct or repair their nests.

Once considered simple and “primitive,” the “reptilian brain is now recognized to govern complex behaviours,” write De Meester and Baeckens. They argue that reptiles show “immense potential” as model species for research into the “mechanisms, the development, and evolution of animal cognition.” “The Reptilian Renaissance”

In fairness, the fact that reptiles can afford to be torpid much of the time due to their low energy needs probably means that they don’t need to exercise intelligence as often as energy-burning mammals and birds do. But that’s a separate matter from not having intelligence.

The reptile brain

Mammals and birds have different types of brains from each other. But if reptiles can demonstrate intelligence similar to that of, say, mammals or birds, is it because they have similar types of brains to either?

At Neuroscience News, Irina Epstein reports that the Max Planck Institute looked at the question in a 2022 paper. They think that a basic ancestral brain developed 320 million years ago when reptiles, birds and mammals (all tetrapods) moved to land. But the subsequent development of their brains was quite different:

Neuroscientists at the Max Planck Institute for Brain Research in Frankfurt tackled this question by generating a molecular atlas of the dragon [lizard] brain and comparing it with one from mice.

Their findings suggest that, contrary to popular belief that a mammalian brain consists of an ancient “reptilian” brain supplemented with new mammalian features, both reptilian and mammalian brains evolved their own clade-specific neuron types and circuits, from a common ancestral set.

“Dragons and Brain Evolution,” September 2, 2022

That suggests that mammals, birds, and reptiles all developed different smart survival strategies on their own. It sounds like convergent evolution or intelligent design.

Complicating the picture is the evidence for smart fish and invertebrates

The manta ray, which has a rather large brain, also has a reputation for intelligence: From the Daily Mail,

Their large brains are also believed to have engorged regions known to play a role in higher functions, such as intelligence, vision and motor coordination.

In addition, manta rays are known to repeatedly revisit the same feeding areas or so-called ‘cleaning stations’ on coral reefs — where cleaner fish will nibble away any parasitic organisms that have attached themselves to the manta.

This behaviour has led researchers to conclude that mantas are able to creative cognitive maps of their environment to help them navigate back to these preferred locations.

They are also known to be highly curious animals and often initiate play-like behaviour with human divers — a phenomenon otherwise really only seen to such an extent in intelligent social marine mammals like dolphins and whales.

Divers also report that mantas actively solicit help when tangled in lines or injured, rather than the fear response more typical of a vulnerable animal.

“How intelligent are manta rays?” July 12, 2019

Other fish can lay claim to intelligence too. So intelligence doesn’t seem to be just a feature of tetrapod evolution.

And then there’s the octopus… Scientists clash over why these invertebrates are smart, as smart as lab rats. And then there are the cuttlefish. And crabs and lobsters too.

But this takes us back half a billion years. Maybe if we are looking for general principles underlying the development of intelligence, we would be wise to leave evolution out of it for a bit.

You may also wish to read: At Quanta: High bird intelligence developed on a different path. High intelligence developing on different paths is consistent with convergent evolution. It’s also consistent with design in nature. But it’s sad when otherwise intelligent people must play the “we’re just another animal” game while demanding attention for ideas that only humans can give.