If you own a dog that is calm around people it knows but barks at strangers or the postman, the reason could be in its feet.
Scientists from Australia monitored a group of 75 dogs, including Labradors, border collies, golden retrievers, Shetland sheepdogs and crossbreeds. These particular breeds were chosen because they were not particularly noted to have high aggression levels.
Their research did not find a connection between left-pawed dogs and their excitability or attention seeking. However, it did find that dogs with a preference for their left paws scored twice as high in aggression toward strangers compared to dogs that preferred their right paws or either paw.
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 Schneider, 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."
The left paw is controlled by the right hemisphere of the brain, which is associated with more negative emotions. Scientists believe the findings reflect what has previously been observed in humans.
"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, from the University of Adelaide, 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 paws."
The findings, published in the Journal of Veterinary Behavior, reflect what has been previously observed in humans. Negative emotions are located in the right hemisphere of the human brain, similar to what was found with the canines.
According to a study in the Journal of Traumatic Stress, because left-handed people tend to be right-brain dominant, they are more prone to fear and anxiety.
"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," Schneider said.
How to determine if your dog is a "leftie" or a "rightie"
If your dog knows how to "shake," which paw does it offer first and most often?
If your dog is given a treat within a toy, which paw does it use to touch the toy first? Which paw is used to hold the toy?
Put a treat under something that is just out of reach of your dog. Which paw does it use to try to retrieve it?
If your dog wants in at the backdoor, which paw does it use to "knock" with?