Dogs cry for joy too

Dogs produce more tears when they meet their familiar people again – which in turn has a touching effect on them. This effect is mediated by the bond-strengthening hormone oxytocin.

Can dogs cry? This question is asked over and over again, also in various Internet forums, and time and time again, the answer from experts is: No. Of course, dogs’ eyes also water, they say, but this has nothing to do with emotions, it only indicates a health problem.

A post in Current Biology (August 22) contradicts this belief. “We’ve found that dogs shed tears because of positive emotions,” says Takefumi Kikusui, a veterinarian at Japan’s University of Azabu. One of his bitches, a poodle, was breastfeeding her dogs and noticed that her eyes were watery.

Of course, this observation does not yet allow for a scientifically established statement. So, Kikusui and his colleagues subjected dogs to a standard measurement of human tears, the Schirmer tear test, before and after what they believed elicited positive feelings in dogs: reunion with their human owners the day after separation. In fact, they measured more tears in the dog’s eyes afterwards than before. Did not work with strangers.