Rats Giggle When Tickled

Tell them a good knock-knock joke, and rats won’t blink an eye. But tickle their soft spots and they’ll burst into laughter — it’s just too high-pitched for humans to hear. Researchers have found that tickled rats emit ultrasonic squeaks of delight and have even identified the part of the brain responsible for this joyful response.

Rats are surprisingly playful. They chase one another, wrestle, and even play games that resemble tag and hide-and-seek. Better yet, they often come back for more, eagerly seeking out another round of tickles — especially on their backs and bellies.