Do dogs cry and shed tears when they are happy or sad like humans?
Do dogs shed tears?
Japanese researchers found an increase in tears produced by dogs when their owners returned after an absence of 5 hours. The research was sparked by prof Takefumi Kikusui when he noticed that his dog had tears in her eyes after nursing her puppies and when he returned home at the end of the day.
In a following study, researchers tested whether dogs secrete tears during reunions with their owners. They found that to be true and in addition that the tear secretion is mediated by oxytocin, a hormone that facilitates caregiving which is why it is also called the love hormone.
They also found that tears in dogs’ eyes could facilitate human caregiving behavior. Dogs can distinguish between blank and smiling human facial expressions so we could expect dogs to be able to learn how to activate certain preferred facial expressions in humans.
Oxytocin increases social bonding between dogs.
Why do dogs shed tears?
Dogs probably shed tears when reunited with their owners as a result of the domestication of dogs by humans.
Domestication and sharing their lives probably led to both humans and dogs learning certain behaviors in order to communicate with each other. It is believed that dogs acquired the cognitive ability to communicate with humans which is superior to any other species that interact or shares space and experiences with humans.
Whether dogs cry depends on the definition of crying
In the human definition of crying, tears are a requirement. We would say crying is an emotional state accompanied by tears. People cry because they are sad, distressed, or happy, in fact, any emotional state could generate tears in humans.
If your dog is in an emotional state because he is happy to see you and simultaneously he produces tears, then we can say dogs do cry. If your dog “cries” by whining, yelping, barking, growling, howling, sighing or groaning, that would not be crying in human terms.
I suppose another question would be whether dogs cry tears when they are emotionally distressed or physically hurt.
Based on the research that emotional tears generated by dogs are a result of the production of oxytocin, we can expect that dogs do not cry because of negative emotions. Oxytocin is the “love hormone” and is produced in response to positive emotions.
If dogs cry (produce tears) in response to negative emotions, that would be the ultimate proof that dogs do cry in the sense that humans understand crying.
Dogs communicate non-verbally
Dogs communicate mostly by body language, so there may be less demand for other forms of communicating emotions, discomfort or unhappiness.
If you observe your dog’s behaviour when you interact with each other, you will notice the body language.
It is often much the same as human body language such as hanging the head, drooping shoulders, listlessness (disinterest), and the like. In addition, dogs use their tails, ears, and tongues in ways that humans don’t.
In conclusion, we could say all dogs cry because they shed tears, but we need more research before we can say dogs cry based on all the emotions we humans understand.