Do dogs cry like we do? The question is debated between those who denounce a form of anthropomorphism and those who consider that our 4-legged friends experience emotions very similar to ours. The findings of a new study tip the scales in favor of the latter. They were published on Monday August 22 in the scientific journal Current Biologyreported the Guardian.
According to this work, it would indeed seem that dogs produce tears when they find their owner after having been separated from them for several hours. In addition, the intensity of these cries would be linked to the levels of oxytocin, the hormone of love and bonding.
The study in question was carried out by a team of Japanese researchers at theAzabu Universityat Sagamihara. Co-author, Professor Takefumi Kikusui explains that it all started with her own experience with her dogs, in particular a female Poodle who had babies 6 years earlier.
He had noticed that his dog’s facial features became more tender when she was nursing her puppies and that her eyes watered at such times. ” This is where the idea came to me that oxytocin could increase the secretion of tears “says the scientist.
A phenomenon that occurs at high intensity only with dog handlers
He and his colleagues began by measuring the volume of tears produced by 18 dogs in their normal environment, at home and with their owner. They then compared it to that secreted during the first 5 minutes when these canids found their master after a separation of more than 5 hours. The teacher Kikusui and his team have thus observed a greater volume of tears produced during reunions than when the quadrupeds were alone at home.
An increase which was not noted in 20 other dogs having found familiar people, but not being their masters. The phenomenon therefore only takes place with the owners.
Another experiment carried out within the framework of this study consisted in asking 74 people to say, on a scale of 0 to 5, to what extent they wished to avoid or, conversely, to take care of dogs whose photos with and without tears in the eyes. Researchers noted that watery canines had 10-15% more participants wanting to care for them. Which suggests, according to scientists, that watery dog eyes trigger this type of emotion in humans.
They also describe the way in which the exchange of glances between dogs and their owners provokes a release of oxytocin in the latter.
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An attitude designed to elicit protective and nurturing behavior
« Through this process, their tears could elicit protective behavior or nurturing behavior in their masters. “says the team.
She adds that this is ” of the first report demonstrating that positive emotion stimulates tear secretion in a non-human animal and that oxytocin plays a role in tear secretion »
Finally, the teacher Kikusui and his colleagues point out that dogs are the only animals to have developed such a high level of communication with humans using gaze and eye contact.