Dog owners know how wonderful it is to come home from a long trip and be greeted by a dog that is wagging its tail, jumping up and down, and licking their face.
A recent study in the journal “Current Biology” suggests that those happy dogs may be shedding more than just fur on your clothes; they may also be tears.
One of the study’s authors, Takefumi Kikusui, said that the idea that animals cry when they are happy, like when they are reunited with their owners, could be a “world first.”
Researchers used a test, which involves putting a special strip under the eyelids, to measure how much tears were in the eyes of the dogs.
To get a baseline reading, they gave the test to the dogs while they were interacting normally with their owners.
When dogs saw their owners again after being away for five to seven hours, they shed “significantly” more tears in the five minutes that followed.
They also found that the dogs’ tears were louder when they were with their owners than when they were with other people they knew.
The researchers think that this emotional response, which makes people cry, is related to the release of oxytocin, which is also called the “love hormone” because it helps people form bonds.
The researchers then wanted to see if the tears had any effect on how the owners felt. They did this by asking the dog owners to rank different pictures of their dogs, with and without fake tears, based on how much they wanted to care for them.
The Japanese research team said, “The dog photos with fake tears were rated much higher than the normal dog photos without tears.”
Kikusui thought that people might pay more attention to their dogs if they had emotional outbursts when they were with them.
The authors say that when babies are upset, they cry, which makes their parents care for them more.
Dogs are the only animals that people have been able to successfully tame, and they have their own unique ways of communicating. It has been shown that eye contact is important for a dog and owner to become close.
In future studies, the researchers want to find out if dogs act the same way around their dog friends.
