Rats "Laugh" When Tickled With Ultrasonic Giggles
If you could hear at frequencies beyond human capability, a tickled rat would sound absolutely delighted. Scientists have discovered that rats emit high-pitched chirps around 50 kilohertz when tickled—sounds that researchers interpret as the rodent equivalent of laughter.
Neuroscientist Jaak Panksepp pioneered this research in the early 2000s after studying play vocalizations in rats for years. He had a breakthrough thought: What if that sound was laughter? So he tickled some rats. The ultrasonic vocalizations were provoked very easily, especially when targeting areas like the nape of the neck—the same spots rats go for during playful wrestling with each other.
What Rat Laughter Sounds Like
These aren't squeaks of distress. Rat laughter comes in the form of 50-kilohertz ultrasonic calls that are completely inaudible to human ears without specialized recording equipment. When researchers slow down and pitch-shift these recordings, they sound like rapid chirping—tiny giggles from tiny creatures.
The most ticklish rats emit the most frequent and robust chirps, and they're also the most naturally playful individuals. It's not just a reflexive sound—it's tied to their personality and emotional state.
Rats Actually Seek Out Tickling
Here's where it gets really interesting: tickled rats develop preferences for the humans who tickle them. In Panksepp's experiments, rats would actively seek out the specific hands that had made them "laugh" previously. Inducing laughter promoted bonding between rats and researchers.
Rats also prefer hanging out with happier rats. When given a choice between two adult rats—one that chirped frequently and one that didn't—young rats spent substantially more time with the apparently jollier companion.
The Brain Science Behind the Giggles
Research published in 2025 linked these reactions to a specific brain region in the somatosensory cortex. When scientists stimulated those neurons directly, rats would giggle even without being physically tickled. The tickle sensation activates particular neurons that trigger the vocalization response.
Another 2025 study in Current Biology found that repeated tickling increases oxytocin receptors in the ventromedial hypothalamus—the same "bonding hormone" system involved in human social attachment. Tickling literally strengthens the social bond between rats and their ticklers.
Why This Matters
This research reveals that play, laughter, and joy are evolutionarily ancient behaviors shared across mammals, not uniquely human traits. The discovery has transformed our understanding of animal emotions and contributed significantly to affective neuroscience—the study of the neural mechanisms of emotion.
It also has practical applications for animal welfare. Researchers now use tickling protocols to improve the wellbeing of laboratory rats, recognizing that positive emotional experiences matter for these intelligent, social creatures. A 2025 study specifically focused on refining tickling techniques to enhance positive welfare outcomes.
So yes, rats laugh when you tickle them. You just need the right equipment to hear their joy.