For centuries, laughter was considered an exclusively human quirk — a sign of our emotional complexity and advanced social lives. But science is now quietly chuckling at that idea. According to a fascinating study out of Lund University, most mammals — and even a few birds — can laugh too.
Yes, really. Rats giggle, elephants let out rumbling chuckles, and sea lions have been known to produce something uncannily close to laughter. The catch? Much of it happens far beyond our range of hearing. Take rats, for example: when they play, they emit high-pitched squeaks in ultrasonic frequencies — essentially, laughter we can’t detect without special equipment.
The realization began when researchers noticed that rats made these squeaks during playtime. Intrigued, they expanded their observations to other mammals and found striking similarities across dozens of species. The patterns were clear:
Put simply, laughter is nature’s way of saying “we’re good.” It acts as social glue, helping animals connect, cooperate, and navigate the sometimes tricky business of getting along.
Just as in humans, laughter in animals changes with age. Younger animals let loose more freely, laughing often during play. Adults, however, use it with more purpose — to signal friendliness, defuse tension, or smooth over social hiccups. It’s less about pure joy and more about communication.
Of course, not every chuckle is cheerful. Some animals use laughter-like sounds in less lighthearted situations — the way we might laugh nervously or sarcastically. These vocalizations can appear in moments of stress, competition, or uncertainty, blurring the line between play and conflict.
The most remarkable insight from Lund’s research is what it suggests about evolution. If both mammals and certain birds can laugh, then the roots of this ability must stretch deep into the past — possibly over 100 million years. Laughter, the scientists argue, likely evolved as an ancient social tool, helping early species communicate, cooperate, and keep the peace.
So, the next time your dog pants happily during a game of fetch or your cat chirps mid-pounce, remember — they might not just be excited. They could be laughing right along with you.
Source: forskning.se / Lund University