As humans, we use laughter to signify enjoyment and comfort among friends. Though its evolutionary origins have always been a bit mysterious, it's a joyous part of human existence that does well to be shared with others.
Thanks to recent studies that collected existing scientific literature regarding animal play behaviors, we now know that the act of laughter is shared among at least 65 other species!
While there has been prior research indicating that a few animals out there have their own form of laughter, namely other primates and rats, new studies show that it's actually far more common than once believed, with at least 65 species sharing the behavior!
Laughter has been found in a variety of primates, dogs, cows, seals, foxes, and mongooses just to name a few. It's also been noted in at least three bird species, including parakeets and Australian magpies.
The study was conducted by primatologist Sasha Winkler and UCLA professor of communication Greg Bryant.
They also categorized the types of laughter by looking at traits of the vocalizations. They'd record how loud the laughter was, whether it was high-pitched or low-pitched, short or long, and whether or not it was a single call or a number of sounds.
Play-language has been seen in many different species for decades now. This behavior can include facial expressions, like what is called "play-face" in primates, and physical body movements, such as "play bows" in canines.
All are used as a diffuser, indicating to the other party that they mean no harm in their actions.
In fact, it almost always looks like fighting, two friendly parties rough-housing as a form of enrichment and bonding. Thanks to play-languages they can continue to have fun safely by communicating with their playmates.
"When we laugh, we are often providing information to others that we are having fun and also inviting others to join," said Winkler, "Some scholars have suggested that this kind of vocal behavior is shared across many animals who play, and as such, laughter is our human version of an evolutionarily old vocal play signal.”
Both Winkler and Bryant have expressed that further research into play vocalizations would be good, but it can be very difficult to come across in the wild as not every play sound is audible to the human ear.
Scientists can get rats to laugh easily by tickling them (yes, really), but their version of laughter is an "ultrasonic vocalization" that can't be heard by human ears.
Meanwhile, primates have a play sound that's extremely similar to human laughter, making it far more recognizable.
By learning more about play sounds, we can relate them right back to us humans, and learn how "human social complexity allowed laughter to evolve from a play-specific vocalization into a sophisticated pragmatic signal,” as Winkler and Bryant put it.
And though the human complexities of laughter are abundant, knowing that it's so deeply entrenched in not just our evolutionary history, but that of potentially hundreds of species across the world, is a beautiful thing!
h/t: Open Culture
