Man’s best friend is losing more than hair.
Dogs cry with joy when reunited with their owners – proof of the powerful emotional bond between humans and their canine companions, according to a new study.
Pooches have tear ducts that gush out of happiness in a variety of situations, including seeing their owners for the first time after long periods of absence, according to Japanese researchers.
“We found that dogs shed tears associated with positive emotions,” Takefumi Kikusui, of Azabu University’s Human-Animal Interaction and Reciprocity Laboratory, said in a statement.
“We also discovered oxytocin as a possible underlying mechanism,” Kikusui said, referring to the so-called love hormone, which produces warm and fuzzy feelings.
In the study, published Monday in the journal Current Biology, Kikusui and his team placed strips of paper known as Schirmer’s tear test inside the eyelids of 22 dogs.
They then measured the amount of tears the mutts produced for one minute before and after reuniting with their owners after being separated for five to seven hours.
After the owner returned, the tears produced increased by an average of 10%, according to the researchers.
In contrast, the researchers did the same with people who weren’t the owners of the dogs and found that the dogs’ tears didn’t increase at all.
To examine the role played by oxytocin, the researchers placed a solution containing the hormone in the animals’ eyes and found that the number of tears increased significantly after the liquid was added, according to the study.
Kikusui said he was inspired to probe the reason for Fido’s emo eyeballs after seeing one of his poodles crying while nursing her puppies six years ago.
The researchers said they still don’t know if, like humans, dogs tear up because of negative feelings. And they don’t know if a dog’s tears serve a social function in the canine world.
But Kikusui said the study shows “dogs have become partners with humans”.
New York Post