Vanderbilt University neuroscientist Suzana Herculano-Houzel tells us, in a recent paper, that tyrannosaurs had a similar number of brain neurons as “primates.”

But how would we know? Herculano-Houzel starts from the assumption that dinosaurs descended from birds and makes a distinction between theropod dinosaurs like the Tyrannosaurus and others:

From that assumption, Herculano-Houzel realized that theropods in particular had a similar correlation between body mass and brain size to pre-impact or basal birds. From there, he used the neuron counts of modern birds like emus and ostriches and applied the same scaling rules to calculate how many neurons theropods like T-Rex might have had.

frank landymore“In terrifying news, the big-brained T-rex may have been as smart as primates” in futurism (January 9, 2023) The document is open access.

This is his case, in his own words:

Here are some thoughts from other research:

First of all, we tend to think that the order of extinct vertebrate dinosaurs is very similar to the reptiles of today and that reptiles cannot be intelligent. But today’s reptiles may be more intelligent than is generally believed. Limits can be practical rather than intrinsic.

Here’s an example: the anole lizard was found to be as capable as the tit (a small bird) in a problem-solving test for a food reward (a larva). But because anoles are exothermic (cold-blooded), they didn’t need many larvae. Not compared to the birds, anyway. Birds are endothermic (warm-blooded). So the anoles had the same problem-solving ability, but they didn’t need it as often because they can just turn off their metabolism. Of course, dinosaurs may have been endotherms like birds rather than exotherms like reptiles, but the difference may not always manifest as a difference in intelligence.

Intelligence tests for life forms should probably take into account questions like: How important is it for this life form to solve this problem soon?

Crocodiles (alligators, alligators, crocodiles) have been reported to use sticks as lures, play games, and work in teams.

All it really means is that endothermy and problem-solving intelligence are not the same thing.

And then there’s the now-famous octopus: the invertebrate controls eight limbs and consequently has a large amount of brain tissue. Perhaps that will allow it to rival mammals in intelligence.

None of this proves that the Herculaneum-Houzel hypothesis is correct; it’s just plausible. Predators tend to be smarter than prey, after all, and exotherms can definitely be smart. In any case, the most accepted thesis of why the entire order dinosaurs they went extinct it’s not that they were all stupid but the planet was hit by an asteroid:

NASA keeps track of potential asteroid impacts today. We are not immune, although we have a better chance of creating defenses than dinosaurs. Whether or not dinosaurs ever used tools.

You may also want to read: Even lizards can be smart, if you catch them at the right time. But can we give machines what the lizard has by nature? What do we want machines to be and do under our guidance that these often seemingly alien life forms are and do spontaneously? Life forms do these things to stay alive. Does it matter then that the machines are not alive?