Left-pawed dogs are more likely to act aggressively towards strangers than their right-pawed counterparts, according to a just-published study in the Journal of Veterinary Behavior.
Although we don’t usually give it a lot of thought, dogs—like people—will inherently use one paw more than another for everyday tasks, like scratching on a door to get in, grabbing a toy, or showing affection. But, if your dog is calm around people it knows but barks ferociously at strangers or the postman, the reason could be in its feet, reports the Deseret News.
Scientists studied 75 dogs, including Labradors, Border Collies, Golden Retrievers, Shetland Sheepdogs and mixed breeds, to establish which paw preference they showed and then analyze their general behavior for various predominant traits to see if lefty or righty’s showed differences in basic aggression level. These particular breeds were chosen because they were not particularly noted to have high aggression levels, the study states.
To determine whether the dog had a paw preference, they were given a circular toy that contained food. Due to the shape, the dog had to hold the toy down with one paw and use the other to retrieve the treats inside.
According to Dr. Luke Schneider of the University of Adelaide, after at least 50 attempts for each animal, they could establish a left, right, or an "ambilateral" (no preference) paw preference. In humans, only about 10 percent are left-handed. However, around a third of the animals tested were classified as left-pawed, a third as right-pawed, and the remainder as being "ambilateral."
"We found that dogs with a preference for left paws were reported by their owners to show high levels of aggression towards strangers," Dr Luke Schneider told The Telegraph.
"The left pawed dogs scored almost twice as high as ambilateral (ones with no preference) and also higher than dogs with right paw preference.”
The left paw is controlled by the right hemisphere of the brain, which is associated with more negative emotions, the researchers state.
They believe their findings reflect what has previously been observed in humans. "There is research in the human world as well that positive and negative emotions can be located in the left and right hemispheres, and it seems to go the same way in humans and other animal species, that the negative emotions are located in the right hemisphere. There are many, many overlaps between human and animal brains," Dr. Schneider said.
According to a study in the Journal of Traumatic Stress, left-handed people tend to be right-brain dominant and are more prone to fear and anxiety, Deseret News reports.
This predictability did not appear to carry over to other emotional reactions, such as excitability and attention seeking, according to the findings.
This study also only involved observing front paws, although dogs also demonstrate preference in the hind limbs, with one usually leading when the dog gallops.