The debate can resume, there is now a biological argument in addition.
Among the great controversies that unleash partisan passions of the century, there is certainly politics, for sure the eternal debate between chocolate and the badly named chocolate bread, but above all, that of the superiority of dogs on the market. cats, or vice versa.
It would seem that a freshly prepared study slices – at least scientifically – the question. An international group of researchers has studied the number of neurons in the cerebral cortex and the size of the brain of several carnivorous animals, to determine in particular whether wild or domestic animals saw their neural composition affected according to whether they need to hunt or not. . Among them therefore, dogs and cats.
And it turns out that if dogs do not have the largest brain in carnivores, they have a fairly high number of neurons, which proportionally ranks them above the striped hyena, the African lion, brown bear… and cat.
“I believe that the absolute value of neurons that an animal possesses, especially in the cerebral cortex, determines the richness of its internal mental state and its ability to predict what will happen in its environment, based on its past experience” , says Suzana Herculano-Houzel , neuroscientist and associate professor at the Vanderbilt Brain Institute who took part in the study.
Intelligence is not just about neurons
The new results invalidate those of previous scientific works which estimated that the dogs had 160 millions of neurons against 300 millions for the cats, and lending to the first 74 grams of brain and 25 grams for the second ones. The new study puts forward 250 million neurons for cats and 530 for dogs.
“Our research means that dogs have the biological ability to do things that are far more complex and flexible than cats. At least we now have a bit of biology that people can summon in their discussions to find out which dog or cat is the smartest, “says Herculano-Houzel.
The number of neurons, however, is not the decisive criterion for intelligence. As Sciences Avenir pointed out after Nicolas Sarkozy’s release, which suspected that only “two neurons of intelligence” were lent to him, the number of neuronal connections as well as the glial cells surrounding the neurons are decisive.
And herbivores are not necessarily victims
Be that as it may, it does not seem that predators have more neurons than their prey, nor meat eaters more than herbivores. Brown bears, for example, have a cerebral cortex that is ten times larger than that of cats, but have the same number of cortical neurons.
Herculano-Houzel claims that although eating meat is widely regarded as a response in terms of higher energy, a more subtle balance needs to be restored, which takes into account the proportions of the brain and body of the different species.
But in terms of neural density, the most badass is probably the raccoon, which has the number of neurons in a dog for a cat-sized brain, making it comparable to primates. The man counts, him, close to 21 billion neurons.