The joys of pandiculation

It's one of my favourite words. "Pandiculation." It's that type of huge yawn where you stretch your arms upwards to the heavens and at the same time stretch out your back and maybe even, on special occasions, your legs too. It's yawning with your entire body.

It's one of those physical pleasures, like scratching an itch, that everyone enjoys. Yawning isn't really about getting in extra oxygen - and there are all kinds of theories about its purpose. But increasingly it's being looked at as a social response, yawning being triggered not by any physical need, but because we're all copycats. When someone else yawns, we yawn.

That goes for animals too. Dogs, who sleep all the time and so aren't even remotely sleep deprived, are always yawning. Researchers have found that what prompts this is hanging around with yawning humans. They're copying us.

Researchers in the United States this week have taken this a step further. Not only are animals inspired to yawn by other creatures, but an experiment wanted to find whether chimpanzees could be made to yawn by a cartoon. Guess what? The chimps watching a cartoon of chimps yawning started to yawn. It's contagious.