London - If your otherwise well-behaved dog barks at the postman, the reason could well be in its feet.
Scientists have found that “left-pawed” canines are more aggressive towards strangers than their “right-pawed” counterparts.
They tested dozens of pets with a special toy to find out which side they favoured and then analysed their behaviour.
The left paw is controlled by the right hemisphere of the brain, which other studies have shown is linked to negative emotions.
The results mirror those for humans as research has shown the same is true of people.
For the canine project, Dr Luke Schneider studied 75 pets, including labradors, border collies, golden retrievers, Shetland sheepdogs and crossbreeds.
They were given a cylindrical toy containing food, which they tried to get out. Because of the shape, the dogs had to use one paw to hold it still and the other to get at the treats inside.
Over at least 50 attempts for each, Dr Schneider, from the University of Adelaide, could establish a left or right preference.
Only 10 percent of humans are left-handed but the ratio was much more even for dogs. Around a third were classed as left-pawed and a third as right with the remainder being “ambilateral” or being able to use both equally.
When owners detailed how the pets behaved with strangers, there was a clear split. The left-pawed dogs scored almost twice as high for aggression than the ambilateral ones and markedly higher than the right-pawed.
None of the dogs in the project were particularly noted for their aggression, it was reported in the Journal of Veterinary Behaviour.
Dr Schneider said: “There is research in the human world as well that positive and negative emotions can be located in the left and right hemispheres.
“It seems to go the same way in humans and other animal species – that the negative emotions are in the right hemisphere. There are many, many overlaps between human and animal brains.”
In 2010, a study found that left-handed people are more likely to be angry, clumsy and awkward because their two brain hemispheres communicate more, spreading negative emotions.
Famously aggressive left-handers include Alexander the Great, Billy the Kid and John McEnroe. - Daily Mail