There are two kinds of people in this world: dog people and cat people. The personalities of these two camps are about as distinctive as the species themselves.

Rancor is not limited to which species is superior but includes heated debates over which is smarter.

According to a recent study, dogs have about “twice the number of neurons in their cerebral cortexes,” leading some scientists to believe they’re the smarter species of the two.

From National Geographic:

One of our most contentious debates may now have an answer.

Dogs, it turns out, have about twice the number of neurons in their cerebral cortexes than what cats have, which suggests they could be about twice as intelligent.

This finding was provisionally accepted for publication and will soon publish in the journal Frontiers in Neuroanatomy. A team of researchers from six different universities in the U.S., Brazil, Denmark, and South Africa contributed to the research.

One of the study’s authors is noted neurologist Suzana Herculano-Houzel. For the past decade, the now Vanderbilt professor has been studying cognitive function in humans and animals. To get as precise a measurement as possible, she starts by counting neurons, a special type of nerve cell found in the brain that transmits messages.

“You take the brain and turn it into a soup,” she said, matter-of-factly, as the first step to finding these neurons. From there, she said, you end up with a number of suspended nuclei from neuron cells that allow the researchers to estimate the number of neurons present.

Why use neurons and why do researchers believe they’re the best rubric for intelligence?

“Neurons are the basic information processing units,” said Herculano-Houzel. “The more units you find in the brain, the more cognitively capable the animal is.”

To make her results-yielding “brain soup,” as she calls it, the research team used only a part of the brain called the cerebral cortex, the crinkly outer layer that sits on top of the brain’s other pieces. While different parts of the brain process outside stimuli like sight and touch, the cerebral cortex puts these stimuli together to drive decision-making and problem-solving, among other functions.

“The cortex is the part of the brain that gives complexity and flexibility,” said Herculano-Houzel.

To get an idea of how many neurons dogs and cats might typically have, the team used three brains—one from a cat, one from a golden retriever, and one from a mixed-breed small dog. Two brains were used to study dogs because the canines vary so greatly in size.

In each of the dogs’ brains, despite varying in size, researchers found about 500 million neurons, more than double the 250 million found in the cat’s brain.

Based on the number of neurons found, they speculated that dogs have roughly the same intelligence as raccoons and lions, while domestic cats have comparable intelligence to bears.

Even if the science is settled here I have no reason to believe argument over the “better” species will end any time soon.

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