Dog owners get the same surge of emotions when looking at their pooch as mothers do with their infants, scientists say.
In a trial they found the owners experienced a burst in the hormone called oxytocin when playing with their pets. Known as the 'cuddle chemical' or 'love drug', it has been found to dampen stress, combat depression, and breed trust in humans.
Playing with dogs releases the 'love drug' oxytocin, according to new research
Biologists Miho Nagasawa and Takefumi Kikusui from Azuba University in Japan, were inspired by their own experiences.
'Miho and I are big dog lovers and feel something changed in our bodies when gazed (upon) by our dogs,' Mr Kikusui told New Scientist.
They recruited 55 dog owners and their pets and took a urine sample from the owners before and after a half hour laboratory play session.
Some owners were put in a control group who sat in a room with their dog and were told to completely avoid the gaze of their pets.
Dog-owners who spent an average of two and a half minutes making eye contact during the play session, experienced a 20 per cent rise in their oxytocin levels.
But the group that avoided looking at their dog were shown to have a slight drop in their oxytocin levels.
Those who spent longer gazing at their hounds tended to rate their relationship with their pet as more satisfying than those who only held a short gaze during play.
Kikusui said that a flood of the cuddle chemical could explain why playing with dogs can lift moods and even improve symptoms of anxiety and depression.
They even suggested that oxytocin might have played a part in the domestication of dogs from wolves, about 15,000 years ago.
'Maybe during the evolutionary process, humans and dogs came to share the same social cues', such as eye contact and hand gestures, said Mr Kikusui.
He added: 'This is why dogs can adapt to human society.'