This hormone could be making your dog aggressive

New York: Do your dogs turn aggressive and start barking, growling or try to lunge the moment they canine see another canine walk by? According to a new research, their hormones are partly to blame for this.

The findings showed that oxytocin and vasopressin -- hormones that are also found in humans -- play an important role in shaping the dogs' social behaviour.

Dogs that reacted aggressively showed higher levels of total vasopressin in their systems, suggesting a link between vasopressin and aggression.

Similarly, oxytocin was found to help inhibit aggression in the dogs, the researchers said.

"Dog aggression is a huge problem. Thousands of people are hospitalised every year for dog bites, especially kids, and aggression is one of the main reasons that dogs get relinquished to shelters," said Evan MacLean, assistant professor at the University of Arizona.

"It would be reasonable to think that if vasopressin facilitates aggression, you could develop pharmaceuticals that could target the vasopressin system to help in cases where dogs are really aggressive."

Better understanding the biology behind canine aggression could help with the development of interventions, the researchers said.

For the study, published in the journal Frontiers in Psychology, the team recruited pet dogs of varying ages, breeds and sexes, whose owners reported struggles with leash aggression.

Further, when oxytocin levels of the pet dogs in the study were compared to a group of assistance dogs, which are specifically bred to have non-aggressive temperaments, the researchers found that the assistance dogs had higher levels of oxytocin and higher oxytocin-to-vasopressin ratios. This supports the idea that oxytocin may help inhibit aggression in dogs.

In addition, the researchers found that aggression problems in dogs appear after some sort of traumatic experience.

"Often it was that the dog was attacked by some other dog and is in a hypervigilant state after that event -- almost like a post-traumatic reaction," MacLean added.