"Dogs are smarter than cats, I know this to be a fact."

"Cats are far smarter than dogs because they do things dogs can't do."

"I've lived with both species and it all comes down to the individual."

For years I've received emails and questions at meetings that essentially boil down to, "Who's smarter, dogs or cats?" And, for years on end, I've given the same answer, namely something that goes, "I really can't tell you because it's not a particularly meaningful question." I know people disagree—some citing what they take to be facts, others relying on their own experiences—each claiming with a high degree of certainty that dogs are smarter than cats or that cats are smarter than dogs. The three quotes above are representative of many more I've received via email or heard in conversations over the years. 

Royalty-free stock photo dreamstime
Source: Royalty-free stock photo dreamstime

So, it's not surprising that the catchy title of a media release called "Sorry, Grumpy Cat—Study finds dogs are brainier than cats" caught my eye, as it did many others, some of whom wrote to me asking what does "brainier" mean and who's smarter, cats or dogs? I know that media titles can be misleading for any number of reasons, including they're meant to attract attention, so I immediately went to this essay and learned about a new and very important study about which I was previously unaware. (For more discussion on how titles can mislead, please see "Do Dogs Really Manipulate Us? Beware Misleading Headlines" about a research paper that really didn't show that dogs manipulate us, according to the researchers themselves.) 

The research essay by Débora J. Alvarenga and her colleagues about which the grumpy cat piece reports is 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 carnivores species." It has been provisionally accepted in the in the open access journal Frontiers in Neuroanatomy and will be available online sometime in the near future.

The abstract of this essay is available online for all to see and nicely summarizes what this team of researchers discovered. For example, carnivores don't have more cortical neurons than herbivores upon whom they feed for a given cortical size. They also report, "Carnivorans stand out in that the usual relationship between larger body, larger cortical mass and larger number of cortical neurons only applies to small and medium-sized species, and not beyond dogs: we find that the golden retriever dog has more cortical neurons than the striped hyena, African lion, and even brown bear, even though the latter species have up to three times larger cortices than dogs." They also discovered that carnivore brains are not affected by domestication, countering claims that individuals of domesticated have smaller brains than their wild relatives. 

In "Sorry, Grumpy Cat—Study finds dogs are brainier than cats" we read "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."

We're also told that the results of this study add a new twist to the question of who's smarter, cats or dogs? So, what does it mean that dogs are "brainier"—they have more cortical neurons, around 530 million—than cats, who have around 250 million? One of the co-authors of the research essay, Suzana Herculano-Houzel, is quoted as saying, "I believe (my emphasis) 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 ... 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." 

Does "brainier" mean "smarter?"

"There are no 'unintelligent' animals; only careless observations and poorly designed experiments" (J. Szentagothai 1987, p 3232)

This surely is a very interesting and important study, but It's a big jump—a leap of fur—to claim that dogs are "smarter" because they have more cortical neurons.1 In various essays and books, I've argued, and other researchers have agreed, that between species companions are fraught with error. For example, in an essay called "Do 'Smarter' Dogs Really Suffer More than 'Dumber' Mice?" I noted that it's become clear that the word "intelligence" needs to be considered in light of what an individual needs to do to be a card-carrying member of his or her species, and that comparisons between species don't really tell us much. So, asking if a dog is smarter than a cat or a cat is smarter than a mouse doesn't result in answers that are very meaningful." Dogs do what they need to do to be dogs, cats do what they need to do to be cats, etc. etc.

In another essay focusing more on brain size that I wrote with Jon Lieff M. D., a neuropsychiatrist specializing in the interface of medicine, neurology and psychiatry, called "The Birds and the Bees and Their Brains: Size Doesn't Matter," we noted, "Big brains and high EQ's2 may be useful for those animals who need them to be card-carrying members of their species, but small-brained animals do very well as long as they can do what they need to do to survive and thrive in their own worlds. The notion that small-brained animals are 'less intelligent' than big-brained animals and 'suffer less' also needs to be revisited as it's surely a myth." We provide numerous examples of small-brained animals who are plenty smart even when compared with larger brained individuals. Sophisticated cognitive abilities have been observed in a wide variety of species and include very unlikely candidates, a point also stressed in The Animals' Agenda: Freedom, Compassion, and Coexistence in the Human Age. 

Along the lines of what I just wrote, in one of the emails I received about this study, former zoo director, David Hancocks, who has been around individuals of numerous and diverse species, wrote, "Measuring braininess is a fatal error that humans make in assessing worth. Cats are as 'brainy' as cats need to be."

I also agree with award-winning Hungarian anatomist János Szentágothai when he wrote, "There are no 'unintelligent' animals; only careless observations and poorly designed experiments."

So, are dogs smarter than cats or are cats smarter than dogs, and does it matter?

So, the question to which the above text leads goes something like. "Are dogs smarter than cats or are cats smarter than dogs, and does it matter?" My take, that's obvious from what I wrote above, is that we don't know and it doesn't matter, unless of course individuals are treated differently if they're thought not to be all that smart and this is mistakenly taken to mean that they don't suffer as much as "more intelligent" individuals of the same or other species. 

I look forward to more comparative research and discussion on questions such as these and others that arise when considering the cognitive and emotional capacities of other animals including dogs and cats. There still is so much to learn about the fascinating cognitive and emotional lives of the nonhumans with whom we share our lives and our magnificent planet. 

1Technically, dogs and cats have fur.

2The EQ is "a measure of relative brain size defined as the ratio between actual brain mass and predicted brain mass for an animal of a given size." Estimates for the EQ's for different species and discussions of what they mean about intelligence and various behavior patterns can be seen here and here


Débora J. Alvarenga, Kelly Lambert, Stephen C. Noctor, Fernanda Pestana, Mads F. Bertelsen, Paul Manger and Suzana Herculano-Houzel. 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. Front. Neuroanat., 2017 DOI: 10.3389/fnana.2017.00118

Szentagothai J 1987 The 'mind-brain' relation: a pseudoproblem? In Blakemore C and Greenfield S (eds) Mindwaves: Thoughts on Intelligence, Identity, and Consciousness pp 323-336. Basil Blackwell: New York

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