Research has shown evidence of an animal sense of humor, revealing that animals have far more in common with us that we ever imagined.
Aristotle once said that “only the human animal laughs.” Until recently, most scientists probably agreed with him. Along with other emotional capacities, laughter and a sense of humor were considered exclusively human traits. But now animal behaviorists and neuroscientists are discovering that humans have far more in common with other animals than we ever imagined, including a sense of humor.
Because animals cannot tell us if they find something funny, scientists have focused on the response to humor—laughter. There are two kinds of laughter: physical and cognitive. Physical laughter occurs in response to physical contact, such as being tickled or engaging in rough and tumble play. Cognitive laughter occurs in response to a joke or other intellectual stimulation.
Jaak Panksepp, a neuroscientist with Washington State University’s College of Veterinary Medicine, studies the origins of emotions. He explains that “neural circuits for laughter exist in very ancient regions of the brain, and ancestral forms of play and laughter existed in other animals eons before we humans came along with our hahahas and verbal repartee.”
So it is not surprising that scientists have observed laughter-like vocalizations in other species, including the humble rat. Using specialized audio equipment, Panksepp discovered that rats produce a high-frequency vocalization when tickled by researchers, when playing with other rats and when mating. Panksepp also discovered that rats that laughed the most played the most, and that laughing rats prefer the company of other rats that laugh.
In response to pleasurable physical contact—such as tickling, wrestling, chasing and other forms of play—chimps, bonobos, gorillas and orangutans produce laughter-like vocalizations, often opening their mouths and exposing teeth the same way humans do when laughing. And, like humans, chimps find laughter contagious, and often laugh simply in response to other chimps laughing, which tends to prolong socializing. According to a study by researchers at the University of Portsmouth in England, chimps also use laughter to cope with unfamiliar relationships, in much the same way as humans might laugh to soften an awkward moment.
Some primates have even demonstrated cognitive humor. Koko, the famous female gorilla who has been the subject of extensive research, is said to know over 1,000 American Sign Language signs and 2,000 words of spoken English. She has sometimes used her impressive vocabulary to engage in sophisticated word play with a humorous edge. For example, she once tied her trainer’s shoelaces together and signed, “Chase!”
Dolphins may not share Koko’s sign language skills, but when it comes to mischievous humor, these aquatic brainiacs can be surprisingly naughty. It is common knowledge among both animal behaviorists and people who live near dolphins that they will occasionally swim silently behind unsuspecting pelicans and then plunge forward and pull their tail feathers, seemingly for no purpose other than the pleasure of pranking a pelican. They have also been observed rolling turtles while swimming and teasing fish by offering bait and then snatching it away.
As for dogs, it appears that they laugh, too. At the Animal Behavior Center in Spokane, WA, researchers Patricia Simonet, Donna Versteeg and Dan Storie discovered that dogs pant a specific when they want to initiate play. To the human ear, it sounds pretty much like a regular pant. But when scientists used a spectrograph to analyze various pants, they found that this particular pant has a different pattern of frequencies. When dogs hear this pant (named the “dog-laugh,” by researchers), they respond favorably with play-bows or play-chasing.
As part of their research project, Simonet, Versteeg and Storie recorded dog-laugh panting and played the recording to shelter dogs. The dogs responded by wagging their tails, playing and engaging in other positive social behaviors. The recording also seemed to help decrease stressful behaviors. The researchers are hopeful that the dog-laugh recordings will soon be widely used to soothe shelter dogs, which could potentially result in faster adoption times.
On a personal level, I have always believed that dogs have a sense of humor. Even without a spectrograph, I can tell when my dog, Spooner, is “laughing” as he steals a ball from me. And when one of Spooner’s much smaller playmates repeatedly leads him into a low hanging branch during games of chase, both dogs seem to be “laughing” every time Spooner falls for it.
Of course, I realize that this is just a connection I am making between my own personal sense of humor and my observation of the dogs’ behavior. And yet, animal behavior expert Jonathan Balcombe—author of Pleasurable Kingdom: Animals and the Nature of Feeling Good (Palgrave Macmillan Trade) and other books on animals—asserts that there is value in making these sorts of connections. He believes that they help us to remember that these other beings with which we share our world are really not so different from us. And then we realize that, as it turns out, we are not alone after all.