Do Rats Like to Be Tickled?

Here’s why we should care.

Rat closeup
Rats make the same noise when being tickled as when they play with each other. Niccirf / Getty Images

Just like people, some rats enjoy being tickled while others don’t love the experience quite so much, a new study finds.

Tickling is an unusual sensation. Some people find it pleasurable and enjoy the giddy response that happens when nerve endings are lightly stimulated. But too much pressure can make tickling uncomfortable and then it’s not so enjoyable. Lab rats feel the same way.

Researchers at the University of Bristol in the U.K. tickled rats, listening to the sounds they made during the process. They used these vocalizations to better understand the animals’ emotional states which ultimately they hope will help them improve the rats' well-being in the lab

Being able to measure a positive emotional response in animals is an important way to improve their welfare, says lead researcher Emma Robinson, professor of psychopharmacology.

“My lab works mainly in the field of psychopharmacology and studying potential new treatments for mood disorders. As part of our work we have developed a method which provides a very sensitive and reliable measure of an animal's emotional state,” Robinson tells Treehugger. “The method looks at how an animal's memory for a particular experience is modified by their emotional state at the time of learning.”

This is called an affective bias, she says.

“Working with our colleagues in animal welfare we decided to see if we could use our affective bias test to measure the emotional response of individual rats to being tickled so we could find out if their vocalizations were a direct reflection of their emotional experience.”

They recorded the sounds the rats made when they were being tickled and compared the number of calls each animal made with its individual affect bias.

They found that not all rats liked to be tickled, although no rat actually hated the experience. They either found tickling neutral or positive and the more calls they made while being tickled, the more positive they found the experience to be.

Rats emits 50-kilohertz calls at a rate that directly reflects how they feel emotionally at the time, Robinson says. They are also more “honest” with their response to tickling than humans and non-human primates.

Sometimes people will laugh while being tickled, even though they don’t enjoy it.

“Laughter in response to tickling in human and non-human primates does not correspond with how much they like the experience with people reporting they did not find tickling pleasant even though they laughed at the time,” Robinson explains.

The findings were published in the journal Current Biology.

Tickling and Stress

Researchers have tickled rats before. They found that when you tickle a rat, it will make a giggle-like squeak, jump happily, and even chase your hand, hoping to be tickled again. 

A 2016 study published in the journal Science found that the somatosensory cortex is the tickle center of the brain. Rats made the same ultrasonic 50-kilohertz giggle when tickled as they made when they were playing with other rats.

However, they were less likely to respond happily to tickling when they were stressed. When the rats were made anxious by putting them under a bright light or elevated on a platform, they weren’t in the mood to be tickled.

Goal of Tickling Research

Researchers hope to use this new laughter information to make life better for rats in the lab.

 “Our main interests from this work are about finding ways which we can easily measure the emotional experience of rats so we can better manage their welfare,” Robinson says.

“What we show here is that listening to their calls could be a way to achieve this. We need to test in other situations but if they find similar results, labs could use calls alone as a way of working out the best ways to positively influence the welfare of laboratory rats.”