A team of researchers is about to publish findings that indicate that dogs have about twice the number of neurons in their cerebral cortexes than cats have. University researchers from Brazil, Denmark, South Africa, and the United States contributed to the study, which is set to be published in the journal Frontiers in Neuroanatomy. Their research indicates that dogs have about the same intelligence as do raccoons and lions, while domestic cats have a level of intelligence comparable to that of bears.
The study found that dogs have about 530 million cortical neurons, while cats have about 250 million. In comparison, humans have as many as 16 billion neurons in our cerebral cortexes, by far the highest number of any terrestrial animal. Among our closest cousins, orangutans and gorillas have about 8 to 9 billion neurons, while chimpanzees have about 6 to 7 billion neurons.
“l 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,” said Suzana Herculano-Houzel, MSc, PhD, an associate professor of psychology and biological sciences at Vanderbilt University and a primary researcher on the project.
One of the most intelligent nonprimate animals the research team has studied is the elephant, which has 5.6 billion neurons. Herculano-Houzel notes that elephants also have higher-than-typical neuron counts in their cerebellums, the part of the brain that controls motor skills; that may help them wield their hefty trunks.