A research study has come up with some nice comparisons of brain size and the number of neurons amongst a selection of carnivores – see below:
- Human – 16 billion
- Gorillas – 8-9 billion
- Chimpanzees – 6-7 billion
- African elephant – 5.6 billion
- Golden retriever – 627 million
- Lion – 500 million
- Hyena – 495 million
- Small dog/mutt – 429 million
- Racoon – 348 million
- Cat – 250 million
- Brown bear – 251 million
- Mongoose – 116 million
- Ferret – 39 million
The number of neurons is not reflected in brain size. For example the brown bear has a brain ten times the size of a cat’s even though the number of neurons is similar.
It is speculated that the dog’s assumed superior intelligence over the domestic cat is due to pack living (social living) as opposed to the solitary lifestyle of the cat. Although domestic cats are adapting to group living, the domestic cat’s wild ancestor is a solitary hunter. A social lifestyle demands more complex behaviors to enable cooperation.
I have used the word ‘assumed’ because the study’s leader, Dr Suzana Herculano-Houzel, stated that she believes that..
“the 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,”
She believes that dogs have the ability to do much more complex things with their lives than cats. She uses the word ‘cats’ but must specifically domestic cats as the lion (living in prides) has almost the same number of neurons as a Golden Retriever.
Brief comment: ‘Intelligence’ is a tricky subject to discuss and compare. And there will be wide variations amongst individuals of a species as we are well aware with respect to people. There are different types of intelligence. This study does not appear to discuss this.
Dr Suzana is the Associate Professor of Psychology and Biological Sciences, of Vanderbilt University in Tennessee. The study was published in the journal Frontiers in Neuroanatomy.