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Sorry, Garfield: Science says dogs are smarter than cats

New research shows that dogs' brains have more than twice as many cells linked to thinking and complex behavior than cats' brains do.
Image: Cute Dog
A cat and a dog at a Blessing of the Animals ceremony at Washington National Cathedral in October 2006.Win McNamee / Getty Images file

Half of you will love this, and half of you will hate it: An international team of scientists says its research strongly suggests that dogs are smarter than cats.

A paper accepted this week for publication in the journal Frontiers in Neuroanatomy reports that dogs' brains have more than twice as many cortical neurons — the cells linked to thinking, planning and complex behavior — than cats' brains do.

Image: A cute dog
A pug dog at the annual Crufts dog show in Birmingham, England, in March 2011.Oli Scarff / Getty Images

The team, working at universities and zoos around the world, counted the number of cortical neurons in eight carnivorans, a large class of mammals that have teeth and claws that allow them to eat other animals. (That's different from carnivores, the much larger class of all meat-eating animals, including bears, raccoons and seals.)

They found that dogs have about 530 million cortical neurons, while cats have about 250 million.

"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," said Suzana Herculano-Houzel, an associate professor of psychology and biological sciences at Vanderbilt University, who developed the method the team used to count neurons.

The research explains why, but first, here's another picture of an adorable dog to help it go down easier:

Image: A cute dog
A dog seen dressed as Moana during the Haute Dog Howl'oween Parade on in Long Beach, California, on Oct. 29.Chelsea Guglielmino / Getty Images file

The research accounted for physical brain size, assessing the number of cortical neurons against the size of the brain they can cram into. And it turns out that dogs have more sheer brainpower even than carnivorans with much larger actual brains — including African lions and brown bears.

Why? The paper puts it this way: "Large carnivorans appear to be particularly vulnerable to metabolic constraints that impose a trade-off between body size and number of cortical neurons."

In other words: Once a species grows beyond a certain size, the energy needed to hunt meat roughly equals the energy the species is able to consume. And because the brain uses more energy than any other organ, there's not enough leftover energy for it to continue developing, evolutionarily speaking.

(The sweet spot appears to have been found by raccoons, which have about the same number of cortical neurons as a dog, but in a brain only the size of a cat's, according to the research.)

"Dogs have the biological capability of doing much more complex and flexible things with their lives than cats can."

"Meat eating is largely considered a problem-solver in terms of energy, but, in retrospect, it is clear that carnivory must impose a delicate balance between how much brain and body a species can afford," Herculano-Houzel said.

Think about it. When was the last time you saw a seeing-eye cat or a cat trained to sniff out bombs?

"I'm 100 percent a dog person," Herculano-Houzel said. "But with that disclaimer, 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.

"At the least, we now have some biology that people can factor into their discussions about who's smarter, cats or dogs."