This week, scientists at Oxford University reported in a new study that dogs developed larger brains than cats over the years because dogs have more sociable brains.

The study analyzed more than 500 species of animals and their development during the course of 60 million years. Fossilized species were included in the samples scientists examined.

The data shows that monkey brains grew the most in relation to their bodies over time; horses, camels, dolphins and dogs follow in the list.

Overall, the information reflected that animals with more social tendencies (i.e. that live and travel in groups, and communicate with other animals) had larger brains and lived in more stable groups. Human brain size has developed much the same way.

Solitary animals (rhinos, deer, cats, etc.) had less development in their brains in the same amount of time.

"Even animals that have contact with humans, like cats, have much smaller brains than dogs and horses because of their lack of sociality,” said Professor Robin Dunbar, co-author of the study.

Previously, scientists thought that brain growth followed a similar pattern for all species of mammal.  This new study, however, indicates that social animals have bigger brains because they need to think more often than solitary animals.

“This suggests that the cooperation and coordination needed for group living can be challenging and over time some mammals have evolved larger brains to be able to cope with the demands of socializing,” said Dr. Shultz, the head author of the study.

The measurements were compared and contrasted with those of other animals to achieve a general idea of how mammal bodies have changed.

“For the first time, it has been possible to provide a genuine evolutionary time depth to the study of brain evolution,” said Dunbar.

To reach reporter Lindy Tolbert, click here.