Dogs have more brain power than cats, say scientists

Dogs are significantly brainier than cats, according to a new study.

While cats have around 250 million cortical neurons – brain cells linked with intelligence – dogs have some 530 million.

Cortical neurons are involved with thinking, planning and other complex behaviours associated with intelligence.

“How many neurons you have in your cerebral cortex, I believe, is a major determinant of your biological capabilities,” said Vanderbilt University neuroscientist Dr Suzana Herculano-Houzel, one of the study’s co-authors.

Dr Herculano-Houzel developed the method for accurately measuring the number of neurons in brains.

“I’m 100 per cent a dog person,” admitted Dr Herculano-Houzel.

That bias aside, she said these findings suggested dogs had the capacity to do “much more complex and flexible things with their lives than cats can”. 

In a Royal Society journal article published last year, neuroscientists Professor Ursula Dicke and Professor Gerhard Roth stated that the number of cortical neurons “comes to mind quite naturally” when searching for a “neurobiological basis of intelligence”.

“At the least, we now have some biology that people can factor into their discussions about what’s smarter, cats or dogs,” said Dr Herculano-Houzel.

The new findings emerged from a broader study, published in the journal Frontiers in Neuroanatomy, investigating the relative brain sizes and numbers of cortical neurons found in a range of carnivorous mammals.

Besides cats and dogs, Dr Herculano-Houzel and her collaborators also measured the brains of hyenas, lions, bears, mongooses and raccoons. 

Hunting requires more intelligence than grazing, so the scientists assumed they would find far higher numbers of cortical neurons compared to brain size in meat-eating mammals than found in their prey.

In fact, it turns out the cortical neuron-to-brain ratio was low in larger mammals like bears. This is the same relationship between number of cortical neurons and size as is found in plant-eating mammals.

A bear’s brain is 10 times the size of a cat’s, but it has about the same number of neurons.

Brains require a lot of energy, and though meat provides plenty of that, the scientists concluded carnivores must strike a balance between investment in brains packed with cortical neurons and overall size.

“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,” said Herculano-Houzel.