The debate is over!
November 29, 2017
The first study to actually count the number of cortical neurons in the brains of a number of carnivores, including cats and dogs, has found that dogs possess significantly more neurons than cats, raccoons have as many neurons as a primate packed into a brain the size of a cat's, and bears have the same number of neurons as a cat packed into a much larger brain.
Credit: Jeremy Teaford, Vanderbilt University
There's a new twist to the perennial argument about which is smarter, cats or dogs.
It has to do with their brains, specifically the number of neurons in their cerebral cortex: the "little gray cells" associated with thinking, planning and complex behavior -- all considered hallmarks of intelligence.
The first study to actually count the number of cortical neurons in the brains of a number of carnivores, including cats and dogs, has found that dogs possess significantly more of them than cats.
"In this study, we were interested in comparing different species of carnivorans to see how the numbers of neurons in their brains relate to the size of their brains, including a few favorite species including cats and dogs, lions and brown bears," said Associate Professor of Psychology and Biological Sciences Suzana Herculano-Houzel, who developed the method for accurately measuring the number of neurons in brains.
(Carnivora is a diverse order that consists of 280 species of mammals all of which have teeth and claws that allow them to eat other animals.)
The results of the study are described in a paper titled "Dogs have the most neurons, though not the largest brain: Trade-off between body mass and number of neurons in the cerebral cortex of large carnivoran species" accepted for publication in the open access journal Frontiers in Neuroanatomy.
As far as dogs and cats go, the study found that dogs have about 530 million cortical neurons while cats have about 250 million. (That compares to 16 billion in the human brain.)
"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," Herculano-Houzel explained.
"I'm 100 percent a dog person," she added, "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."
This. Means. War.
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