Oxytocin may have turned dogs into man’s best friend

Chuck Bednar for redOrbit.com – @BednarChuck

Oxytocin, the so-called love hormone, may be the reason that dogs evolved into “man’s best friend”, and dogs who were given a dose of the neuropeptide performed better at following cues to find a hidden treat, according to new research from Monash University in Australia.

Jessica Oliva, who carried out the research as part of her Ph.D. studies in biological sciences and is lead author of a paper published last month in the journal Animal Cognition, explained that the findings provide new insight into exactly how dogs formed such a strong bond with humans.

In addition, she told ABC Science Online that the research could also make it possible to breed dogs that are even better at understanding human cues. Previous studies have found that oxytocin affected dogs and humans in much the same way, making them more trusting and cooperative.

For instance, Oliva said that patting and talking to a dog for just three minutes actually increased oxytocin levels in both people and canines, and other research has shown that the amount of the hormone in a dog’s urine increases based on the strength of its relationship with a human.

“So that really seemed to suggest that oxytocin is involved in feelings of closeness to your dog,” she told the website. However, Oliva and her colleagues noted that measuring the oxytocin levels in the blood of a canine does not necessarily indicate what is going on in the animal’s brain.

The test oxytocin’s impact on a dog’s ability to pick up and use human social cues in order to find food treats hidden in one of two bowls, the researchers recruited a total of 62 dogs (31 males and 31 females) and tested them on two separate occasions, between five and 15 days apart.

The dogs were administered either an oxytocin nasal spray (to ensure that it would easily reach the brain) or a saline placebo 45 minutes prior to the start of each session, and their performances were graded on a scale of one to 10. The dogs then took part in two trials in which one researcher gave them a momentary distal pointing cue, and two in which a gazing cue was used.

The results showed that dogs who were given oxytocin outperformed those that did not receive the chemical, ABC Science Online said, and the enhanced performance was still apparent up to 15 days after the neuropeptide was last administered. The results, Oliva explained, demonstrate clearly that oxytocin is “definitely involved in a dog’s ability to use human cues.”

She went on to explain that scientists have previous demonstrated that dogs are better at using non-verbal human cues such as pointing than their wolf ancestors, even if the latter are reared by people and wind up being highly socialized. She hypothesizes that something must have occurred in a dog’s brain during the domestication process to explain the phenomenon.

“That would really tell us more about evolution,” Oliva said, adding that some dogs featured in the experiment performed better at the task than others. She is currently investigating to see if there is some genetic difference in the oxytocin receptor genes in the dogs that performed better, and if she find any, it could lead to selective breeding of canines for use as guide dogs, police or military dogs, or customs dogs.

Researchers from the Animal Welfare Science Centre at the University of Melbourne and the Life and Environmental Sciences Department at Deakin University in Geelong, Australia, were also involved in the study, which was published online by the journal on February 3.


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