I don't really have a dog in this fight, no pun intended, but you would be wrong. The only modern study that looked at neurons of carnivorous animals including cats/dogs found that dogs have nearly twice the number of neurons in the cerebral cortex, and the ratio of cortical neurons to overall neurons is also higher (~20% vs ~23%).

https://www.frontiersin.org/articles/10.3389/fnana.2017.0011...

I know very little about brains in general but I would guess that the number of synapses (connections between nuerons) has more to do with intelligence than the number of neurons themselves. Could be that this scales exponentially. I think it's much easier to count neurons tho, seems like we have good numbers for lots of species.

Worth considering that African elephants have 3x the nuerons we do, Killer Whales twice as many only counting the cerebellum.

Cool list: https://en.wikipedia.org/wiki/List_of_animals_by_number_of_n...

It's interesting right! But it turns out elephants have about a third of the cortical neurons as humans, presumably they need more brain capacity to handle being enormous.

Orca, on the other hand, have more cortical neurons than we do, and much larger brains in general. Part of that is clearly that they have an incredible sense we don't, the ability to make three-dimensional maps out of sound, but orca are also remarkably complex beings and I don't have too much trouble believing that they're about as smart as us, just in a very different way that doesn't involve tools.

Ah. Turns out my numbers are based on packing density, while the study you cite is based on counting neurons. (I'm assuming here counting is the better choice :)

The main point remains either way - equating numbers of neurons with "smart" is a really odd definition of "smart". (I mean, most definitions of "smart" in animal studies are bonkers - the most common one is "is obedient")