It was often thought that dogs only empathize with people in need but never do they cry. However, a new study from Japan suggests otherwise. According to the study, dogs might cry when reunited with their human parents.
Researchers carefully selected 18 dogs without separation anxiety and measured their daily tear production. They captured each dog's tears when together with their parents and compared them to their tears when reunited with their parents after being separated for five to seven hours. The result was that the dogs teared up significantly during the reunion.
When separated for a while and reunited with their parents, dogs display affiliative behaviors such as licking their parent's faces, jumping on them, and wagging their tails. During these times, oxytocin (the love hormone) is released into their system. Researchers believe that dogs emit tears during reunions because of oxytocin, and it causes their parents to want to comfort them.
Researchers displayed pictures of dogs with artificial tears and dogs without artificial tears. They then asked people to rate how much they wanted to care for the dogs. Most people ranked dogs with artificial tears higher than those without artificial tears. The result shows the existing human-canine bond.
Interestingly, the study didn't mention dogs' breeds and how that impacted the study. Therefore it is safe to assume that it applies to most dog breeds.