We aren’t the only ones to laugh. In fact, it might not be a surprise to learn that other primates laugh such as chimpanzees, gorillas, bonobos and orangutans show laugh-like vocalizations, but you might be surprised to learn that dogs and rats laugh too! Rats emit short high frequency sounds during play or when tickled. The vocalization is so high pitched that humans can’t hear it. The rats have been found to have what is called “tickle skin” which is found on certain prominent areas over the body. Tickling between the experimenters and rats leads to social bonding and the rats are then conditioned to seek tickling.
Dogs laugh as well. The laugh sounds very similar to a pant to the human ear, but with the help of specialized equipment burst of frequencies can be measured to indicate laughing. Just like in humans, the social laugh in dogs initiates play behaviour and decreases stress hormones. In a 2005 study conducted by Patricia Simonet, Donna Versteeg and Dan Storie where one- hundred-and-twenty dogs were measured across stress behaviours including growling, salivation, pacing, barking, panting, cowering, and lunging. The dogs were compared with each other across a baseline and found that when the laugh track recording was played, they showed an increase in tail wagging and displays of play face. They also showed more social behaviour such as approaching and lip licking. It seems therefore that humans aren’t the only ones to benefit from a good laugh!
Most behavioural psychologists agree that animals and humans laugh in a much different way and while we both laugh for social reasons, animals still lack the underlying self-awareness to laugh exactly like we do so in that sense laughter is somewhat unique to humans.
Above: Rats laugh!