Like humans, dogs have tear ducts that are filled with tears to keep their eyes clean and healthy. But tears in dogs that do not tend to fall as they do when humans cry, It has not been associated with passion before.
Takefumi Kikusui, a professor in the Laboratory for Human-Animal Interaction and Reciprocity at Azabu University in Japan, decided to investigate canine tears after witnessing a standard poodle when she had puppies six years ago. Notice that her eyes watered as she breastfed her dogs.
“We’ve also come to discover oxytocin as a possible mechanism behind it,” Kikusui said, referring to the hormone sometimes called in humans the love or mother hormone.
To verify the link, Kikusui and his team measured the amount of tears among 18 dogs with a standard test known as the Schirmer tear test. He. She It included a paper tape that was placed inside the dogs’ eyelids for a minute before and after they were reunited with their owners after five to seven hours of parting.
“The size of the rupture was assessed by the length of the wetted portion of the STT. Baseline was approximately 22 mm, and owner reunification increased by 10%,” Kikusui explained via email.
With the help of 20 dogs, researchers compared the amount of tears before and after they were reunited Owners and people with whom the animals were familiar. Only the reunion with the owner increased the amount of tears.
To understand whether oxytocin plays a role in tear production, a solution containing the hormone was applied to the surface of 22 dogs’ eyes. The amount of tears increased significantly after oxytocin was applied, compared to the control solution.
There’s still a lot researchers don’t know about dog tears. Humans often cry in response to negative emotions, but the researchers did not test whether dogs did the same either. Nor do they know if a dog’s ability to tear up plays a social role in dogs Globalism.
Kikusui said Humans could have taken better care of the dogs that got the tears. His team showed 74 People He photographed the faces of dogs with artificial tears inside and without artificial tears and asked them to arrange the animals. People gave more positive reactions when they saw the dogs with teary eyes.
“Dogs become partners with humans and we can form bonds,” Kikusui said in a statement.
