Laughter makes bonobo monkeys more cheerful, scientists say

Have you ever heard the saying: "Laughter is the best medicine"?

For years, it's been known that when we laugh our bodies release chemicals called endorphins - hormones which make us feel good.

Now, scientists say it could also be the case in the animal kingdom too.

They've found that bonobos become more cheerful after they hear other bonobos giggling!

What did scientists find?

Researchers at Indiana University in the US trained bonobos to recognise two different boxes - a black box and a white box.

The black box always contained a delicious food snack and white one was always empty.

After scientists had trained the bonobos to always approach the black boxes and to avoid the white ones, they decided to add in a third box into the mix.

Experts would then either play the sound of bonobo laughter or a control sound - before presenting the chimpanzees with a grey box that they had never seen before.

Dr Sasha Winkler, the lead author of the study, explained: "We know that other apes, like chimpanzees, have contagious laughter during play.

"We were wondering if that behaviour could be explained by positive emotions produced from the sound itself," she added.

The team found that the chimpanzees were much more likely to approach the grey box after hearing the sound of bonobo laughter, treating them like a reward box - which indicated a more optimistic expectation of finding a treat.

Experts say their results suggest that hearing laughter brings about positive emotions and may therefore influence bonobos' decision making.

They also think it could help offer clues about how humans developed emotion.

"Studies like ours can help to untangle the evolutionary building blocks of empathy, communication, and cooperation in humans," Dr Winker added.