By Kim Gilliam

Dog owners say their pets are smartest because they are loyal, joyful and trainable. Cat owners say their pets are smarter for completely different reasons; cats are independent, cunning hunters with boundless curiosity.

So, which pet has the edge over the other?

We now officially know the answer to this age-old question, and some of you aren’t going to like the answer. A team of researchers counted the number of neurons in dog and cat brains and found that one had twice as many as the other. The answer is … dogs. At least when it comes to raw brain power.

A study published in the journal Frontiers in Neuroanatomy in December 2017 counted cortical neurons in the brains of eight different carnivorous animals. The dogs studied included a golden retriever, which had 627 million neurons, and a smaller
mixed breed dog with 429 million. The cat studied had 250 million neurons by comparison.

Dogs had the most neurons of any carnivore, even though they didn’t have the biggest brains. They were found to have about as many neurons as a raccoon and lion, while the cat’s neuron count was similar to that of a brown bear. Previous studies indicating carnivores need greater brain capacity than prey appear to be unfounded. It now appears that there isn’t much difference at all.

Neurons are where the brain processes information, so the more of them an animal has, the more cognitive ability it has, i.e. the more information it is able to process. Cortical neurons are thought to be responsible for decision-making and problem-solving. As you might expect, humans have a great many more, with an average of about 16 billion neurons, whereas orangutans and gorillas have about 8 to 9 billion.

“I believe the absolute number of neurons an animal has, especially in the cerebral cortex, determines the richness of their internal mental state and their ability to predict what is about to happen in their environment based on past experience,” neuroscientist Suzana Herculano-Houzel from Vanderbilt University said. “Our findings mean to me that dogs have the biological capability of doing much more complex and flexible things with their lives than cats can.”

Note that neurons are not the only one way of measuring intelligence – some consider brain size and structural complexity for example. It’s also important to note that researchers suggest caution in pitting different species against each other in a study such as this, as different species are often intelligent in different ways, each shaped by evolution to solve the problems in their natural habitat.

The bottom line? Cats and dogs are likely “geniuses” within their environment, no matter how many neurons they have.

Kim Gilliam co-owns Frolick Dogs, an indoor dog gym in Alexandria, with her husband, Kevin Gilliam.