If you thought laughter was just a human trait, you couldn’t be more wrong. Many animals have their own unique ways of expressing joy. If you’ve ever watched a dog with its tongue flopping out or seen ...

Human laughter is common, but it’s a somewhat mysterious part of our evolution. It’s clear to evolutionary scholars that we laugh as a part of play, signaling our cooperation or friendliness. But how ...

If you tickle a rat's belly, it squeals with laughter. However, we are unable to perceive this laughter as its frequency, around 50 kHz, exceeds the range of human hearing. Neuroscientist Jaak ...