Discoveries

September 06, 2022

Tears of Joy

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It can be a tearing-up moment to see an owner reunited with their dog after a long period of time.

But it’s not just the humans who are crying, NPR reported.

A new study found that dogs can shed tears when reunited with their owners or with other familiar humans.

For their paper, researchers placed small pieces of filter paper inside the pooches’ lower eyelids to measure the volume of tears dogs shed before and after reunions – better known as the Schirmer tear test.

The tear volume was assessed in the dog’s home environment with their owners present and again shortly after the pets and their owners were reunited after being separated for five to seven hours.

The team also conducted the same experiment with humans familiar to the dogs that weren’t their owners.

Unsurprisingly, the findings showed that the canines would “cry” more when reunited with their owners than with familiar people.

The study provides evidence that humans are not the only creatures capable of shedding tears because of an emotional response.

Still, Jessica Meekins, a researcher at Kansas State University, questioned the results, noting that tear production varies between animals and species.

She added that future studies should look into the composition of the tears to determine an emotional trigger, such as hormones, electrolytes and proteins.

“It would be interesting to know… whether those tears contain similar molecules to what’s been identified in people in certain studies and in trying to investigate why we cry,” Meekins said.

This story originally appeared in the September 06, 2022 newsletter, Pinned Down.