JOIN USA new study set to put an end to the intelligent-pet debate has claimed that their friendly character has helped dogs to develop bigger brains than cats.
It was often thought that the feline pet was smarter than its canine counterpart because it needed less attention but researchers at the Oxford University have discovered that cat's brains are smaller because they are less social.
The intelligence of "a man's best friend" has evolved at a greater rate than the less social cat over millions of years, they said.
This is for the first time, scientists have charted the evolutionary history of the brain across different groups of mammals over 60 million years and identified huge variations in how their brains have changed, the Telegraph reported.
The researchers found that there was a link between the size of an animal's brain in relation to the rest of its body and how socially active it was.
Dr Susanne Shultz, who led the research, said: "Dogs have always been regarded as the more social animals while cats like to get on with their own thing alone. But it appears that interaction is good for the brain and extends to other species, like ourselves.
"We are even more social than monkeys and apes and it is this ability to get on with each other that has helped us dominate the planet.
"This study overturns the long-held belief that brain size has increased across all mammals. Instead, groups of highly social species have undergone much more rapid increases than more solitary species."
For their study, published in Proceedings of the National Academy of Sciences, the scientists analysed available data on the brain and body size of over 500 species of living and fossilised mammals.
They found that the brains of monkeys grew the most over time followed by horses, dolphins, camels and dogs.
It was also found that groups of mammals with relatively bigger brains tended to live in stable social groups, while the brains of more solitary mammals such as cats, deer and rhino, grew much more slowly during the same period.
Previous research had suggested that the growth rate of the brain relative to body size followed a general trend across all animal groups.
But the new study overturns this view, showing there is a wide variation in patterns of brain growth across different groups of mammals and not all of them have larger brains -- suggesting social animals had to think more.
Dr Shultz said: "This suggests the co-operation and co-ordination 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 socialising.
"All dogs are quite good at solving problems, which gives credence to the traditional image of the cunning fox which is a member of the same family. Dogs descended from wolves which appear to have the biggest brains as they live in large family groups."