The "mutual gaze" between dogs and their owners can lead to a bond that is similar to the one between a mother and child, a team of Japanese scientists have revealed.
Humans also experience the same feelings of affection for their dogs as they might do for their family, they found.
"It can be said that dogs successfully cohabit with humans because they have been successful in adapting the bonding mechanism to relations with humans," explained lead author Miho Nagasawa from Azabu University, Japan.
During the study, dogs were observed for 30 minutes in a room with their owners. The amount of time the dogs made an eye contact with their owners was used to put the dogs into two groups: long gaze and short gaze.
The dogs that gazed at their owners the most saw a significant increase in their oxytocin levels after the experiment.
In the second experiment, oxytocin was sprayed onto the nose of some dogs. The dogs were put into a room with their owner and two strangers for 30 minutes. The team discovered that female dogs looked at their owners for longer and owners of these dogs released more oxytocin.
"The lack of an effect on male dogs could be down to sex differences in the function of oxytocin," the authors wrote.
The results show the existence of a continuous bonding loop between humans and dogs driven by oxytocin. Eye contact between a mother and her baby strengthens their attachment by activating the so-called 'love hormone'-- oxytocin -- in the mother's brain.
This drives emotional bonding between parent and offspring by encouraging both nurturing and interactive behaviours.
The findings were detailed in the journal Science.
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