By Dr. Becker
Do rats laugh?
As it turns out, yes, they do!
A neuroscientist at Washington State University by the name of Jaak Panksepp noticed that when young rats in his laboratory were grouped together, the instruments he uses to hear high frequency rat sounds picked up lots of little chirping noises.
Young rats make these same chirping sounds when they play together, and given the choice, they prefer to spend time with other rats who chirp at the same 50 kHz frequency. The chirps seem to be indicators of rat happiness – they make the same sound when dopamine circuits in the brain are stimulated. In addition, the high-frequency ultrasonic chirps are distinct from other sounds rats make.
Dr. Panksepp wanted to find out whether the rat chirps he was hearing were, in fact, the sounds of laughter. So he decided to conduct a highly sophisticated scientific experiment – he set out to tickle some rats.
Panksepp discovered the rats’ chirping increased dramatically when they were tickled. And the more they were tickled, the fonder the rats grew of the researcher doing the tickling. Scientists have also discovered rats will run mazes and press levers if tickling is their reward.
Rats Bond with Their Ticklers
Humor and laughter in animals other than humans has not been the subject of much study. According to the magazine Scientific American:1
“Aside from anecdotes, we know very little about nonhuman primate laughter and humor, but some of the most significant findings to emerge in comparative science over the past decade have involved the unexpected discovery that rats – particularly juvenile rats – laugh. That's right: rats laugh. At least, that's the unflinching argument being made by researcher Jaak Panksepp, who published a remarkable, and rather heated, position paper on the subject in Behavioural Brain Research.”2
Dr. Panksepp and his research assistants have conducted many studies on rat laughter in recent years, and they’ve discovered similarities between the chirping in young rats and laughter in young children.
Rats are especially ticklish in the nape area, which is also the area young rats tend to target when they play together. Panksepp discovered the most ticklish rats are also the most playful. Even more interesting, the rats appear to bond with their ticklers – the animals seek out specific human hands that had tickled them previously.
“Young rats have a marvelous sense of fun.”
Some scientists aren’t convinced the sounds rats make when tickled qualify as laughter, but Dr. Panksepp has been busy gathering evidence of the similarities between the chirps of young rants and human laughter.
In a paper3 published in Science magazine a few years ago, Panksepp made this observation:
“Although no one has investigated the possibility of rat humor, if it exists, it is likely to be heavily laced with slapstick. Even if adult rodents have no well-developed cognitive sense of humor, young rats have a marvelous sense of fun. We have already bred rats that exhibit playful chirping, and thereby hope to track down some of the genes for joy. Perhaps we will even stumble on new molecules to alleviate depression as well as some excessive-exuberance disorders.”
Here’s a short video of Dr. Panksepp’s rat tickling experiment: