It used to be: Dog vs. cat, Who’s smarter? Now it’s Bird vs. reptile: Who’s smarter? Experts on the fascinating world of animal intelligence are locked in a debate over whether number of neurons or brain volume indicates intelligence (cognitive capacity):

In previous work, [Pavel] Němec and colleagues showed that birds have high neuronal densities. “They basically compensate, with these densely packed neurons, [for] the fact that they have relatively small brains in absolute terms, but they have just as many neurons as mammals,” he says. But they didn’t know whether that was true of reptiles as well. In the new study, the researchers found that reptiles have very low neuronal densities, with an average neuron number 20 times lower than that of birds or mammals of similar body size.

Sophie Fessl, “Reptiles are the Real Bird Brains” at The Scientist (March 22, 2022)

So that measure would favor the birds, But some don’t want number of neurons to simply replace brain size as a simple measurement:

Barbara Finlay, a cognitive neuroscientist at Cornell University who was not involved in this study, says that the researchers present a “useful piece of information,” particularly basic data long missing about reptiles. However, she questions whether neuron numbers—or any other single factor—in isolation can really be a proxy for computational power. “Counting up numbers does not equal cognition,” she tells The Scientist.

Additional information about the brain’s morphology and connectivity, as well as the way different types of neurons are packed into a brain region, would improve brain power estimates, Finlay says. “Brain mass has many aspects that anchor its computing power. Since neurons vary widely in size and synaptic density across structures and species, the number of synapses, the organization of single regions, the overall network structure of the brain and brain energy consumption are all important,” she adds in an email to The Scientist.

Sophie Fessl, “Reptiles are the Real Bird Brains” at The Scientist (March 22, 2022)

It’s true that brain size is not a very good measurement. Lemurs with brains 1/200 the size of chimps’ pass same IQ test. And even lizards can be smart.

Might there be another way of looking at it? From recent reports about bird smarts in the science literature, here’s the standard reptiles must beat or match:

➤ Some birds can recognize faces, which is not thought to be common in the bird world.

Some penguins match the vocal calls of fellow penguins to their faces or other aspects of their physical appearance, making them the first birds besides crows known to have this double-sense recognition ability.

Christa Lesté-Lasserre, “Penguins have rare ability to recognise each other’s faces and voices” at New Scientist (October 12, 2021) The paper is open access.

We don’t know for sure that the African penguin’s ability is rare. It hasn’t been studied much.

➤ Many birds learn their parents’ calls while they are still in their eggs:

Over a decade ago, behavioral ecologist Diane Colombelli-Négrel was wiring superb fairy wrens’ nests to record the birds’ sounds when she noticed something odd. Mother fairy wrens sang while incubating their eggs, even though it would have made more sense to keep quiet to avoid attracting predators…

For birds such as superb fairy wrens (Malurus cyaneus) that perfect their songs with parental tutoring, it was thought that sound perception began well after hatching. But when it became obvious that mother birds were intentionally singing to their eggs, “we knew we were on to something,” says avian ecologist Sonia Kleindorfer of the University of Vienna.

Lesley Evans Ogden, “Some birds learn to recognize calls while still in their eggs” at ScienceNews (September 16, 2021)

Apparently, the unhatched wrens learn a “vocal password” from their mother that helps distinguish them later from parasitic cuckoo nestlings. Four other species of birds were also found to communicate with their unhatched offspring. Human babies also recognize their mothers’ voices while they are still in the womb, which may also help with bonding later.

➤ Australian magpies outwit scientists by helping each other remove tracking devices:

During our pilot study, we found out how quickly magpies team up to solve a group problem. Within ten minutes of fitting the final tracker, we witnessed an adult female without a tracker working with her bill to try and remove the harness off of a younger bird.

Within hours, most of the other trackers had been removed. By day 3, even the dominant male of the group had its tracker successfully dismantled.

Dominique Potvin, “Altruism in birds? Magpies have outwitted scientists by helping each other remove tracking devices” at The Conversation (February 21, 2022)

PBS, offers a detailed but inconclusive discussion about what the birds could have been thinking. But the main point is that they were able to perceive the situation clearly enough to act in concert to remove the trackers at all.

So that is the standard reptiles must beat. Will they beat it? Stay turned!

Note: The recent paper by Pavel Němec and colleagues arguing for number of neurons as the winning ticket is open access.

You may also wish to read: Spiders are smart; be glad they are small Recent research has shed light on the intriguing strategies that spiders use to deceive other spiders — and prey in general. Invertebrates like spiders and octopuses can be smarter than we used to think and we are only beginning to discover their many strategies. (Denyse O’Leary)

and

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 is it that we want machines to be and do under our guidance that these—often seemingly strange—life forms are and do spontaneously? The life forms do those things to stay alive. Does it matter then that machines are not alive?