Are mammals the only animals that yawn? © Getty Images

Are mammals the only animals that yawn?

We aren't alone in the animal kingdom when it comes to having a good yawn.

Asked by: Fernando Sasso, by email

Advertisement

No. If you mean opening the mouth very wide and breathing deeply then some fish, birds and even snakes yawn. Baboons, guinea pigs and Siamese fighting fish yawn to show aggression. Some penguins yawn during courtship rituals (but presumably not because they’re bored). Some snake’s yawn after a good meal. We don’t yet understand all the many functions of yawning.


Advertisement

Subscribe to BBC Focus magazine for fascinating new Q&As every month and follow @sciencefocusQA on Twitter for your daily dose of fun science facts.