Why brainy tail-wagging top dogs can teach aloof cats a thing or two

By DAVID DERBYSHIRE

Top dog: Scientists claim pet dogs are smarter than cats because friendly social mammals need more intelligence than solitary, aloof ones


Looking down on the world – and especially those tail-wagging dimwits known as dogs – may seem like the natural order of things for cats.

No longer. For scientists yesterday claimed pet dogs are smarter than their feline counterparts.

The reason, they claim, is that dogs evolved bigger brains because friendly, social mammals need more grey matter than solitary, aloof ones.

The findings, which are bound to divide pet owners around the world, come from a study into the brain size of more than 500 species of living and fossilised mammals.

The researchers at Oxford University charted the evolution of mammal brains over the last 60million years – from a few million years after the dinosaurs became extinct to the modern day.

They discovered that there is a strong link between the size of a brain relative to an animal’s body and how sociable that creature is.

Sociable mammals such as whales, dogs, dolphins and humans tend to have much larger brains compared to their bodies. Solitary species – such as tigers, domestic cats and rhinos – have less grey matter, the scientists found.

Prof Robin Dunbar, co-author of the study, said: ‘For the first time, it has been possible to provide a genuine evolutionary time depth to the study of brain evolution.


‘It is interesting to see that even animals that have contact with humans, like cats, have much smaller brains than dogs and horses because of their lack of sociality.’

The study, published in the journal Proceedings of the National Academy of Sciences, found that the brains of monkeys expanded the most over evolutionary history, followed by horses, dolphins, camels and dogs.

Groups of mammals with relatively bigger brains tend to live in stable groups, they found.

The researchers believe that living in a group is more demanding mentally than having a lonely existence.

The study is also challenging previous research which suggested the brains of all mammals evolved to be larger at a similar rate.

Co-author Dr Susanne Shultz 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.

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.’

source: dailymail