Dogs Have Bigger Brains Than Cats Because They Are More Sociable, Research Finds

Over millions of years dogs have developed bigger brains than cats because highly social species of mammals need more brain power than solitary animals, according to a study by Oxford University.

The research team analysed available data on the brain size and body size of more than 500 species of living and fossilised mammals. It found that the brains of monkeys grew the most over time, followed by horses, dolphins, camels and dogs. The study shows that groups of mammals with relatively bigger brains tend to live in stable social groups. The brains of more solitary mammals, such as cats, deer and rhino, grew much more slowly during the same period.

The research team used available data of the measurements of brain size and body size of each group of living mammals and compared them with similar data for the fossilised remains of mammals of the same lineage. They examined the growth rates of the brain size relative to body size to see if there were any changes in the proportions over time. The growth rates of each mammal group were compared with other mammal groups to see what patterns emerged.

Source:

http://www.sciencedaily.com/releases/2010/11/101127105348.htm

Original Paper:

S. Shultz, R. Dunbar. Encephalization is not a universal macroevolutionary phenomenon in mammals but is associated with sociality. Proceedings of the National Academy of Sciences, 2010; DOI: 10.1073/pnas.1005246107