Dogs also 'cry' because they are happy to see their owners again

Dogs also "cry" because they're happy to see their owners again, according to a new study by Japanese scientists.

According to Agence France-Presse, Japanese scientists just published a study in the journal "Current Biology" on August 22 and found that dogs also cry when they see their owners again after being separated for a long time.

New research by Japanese scientists shows that dogs also cry for happiness

"We've never heard of animals shedding tears in happy situations, such as being reunited with their owners," said Takefumi Kikusui, a professor at the Human Interaction Laboratory at Azabu University in Japan and one of the study's authors.

Scientists measured the amount of tear fluid in the dogs' eyes using the Schirmer test. This is a widely used test that checks tear volume by placing a strip of special filter paper over the eyelid. The team tested the dogs during normal interactions with their owners.

The researchers found that when dogs were reunited with their owners after being separated for five to seven hours, the number of tears they produced "significantly increased" over the next five minutes.

New research by Japanese scientists shows that dogs also cry for happiness

They also found that dogs who met their owners shed more tears when they were reunited with other people they knew.

According to the researchers, this response may be related to the release of oxytocin, also known as the "love hormone" because of its involvement in building relationships.

The scientists then tried to test whether the tears had an emotional impact on the dog's owners. To do this, the team asked dog owners to rank different photos of when their dogs had artificial tears and when they didn't, according to how much they wanted to care for them.

"Photos of dogs in tears ranked significantly higher than photos of dogs in normal conditions," the study reads.

New research by Japanese scientists shows that dogs also cry for happiness

"Dogs that cry when interacting with their owners are likely to receive more care from their owners," Kikusui hypothesizes.

Over time, dogs have developed specific communication skills. Eye contact has been shown to play an important role in forming a bond between a dog and its owner.

In future studies, the researchers wanted to test whether dogs produced similar tears when they encountered other dogs.