(Image: Alessandra Zannella, Ivan Norscia, Roscoe Stanyon and Elisabetta Palagi)

Don’t worry, you’re not boring this lemur. An unexpected reason for yawning in these primates has been revealed for the first time.

Elisabetta Palagi from the University of Pisa in Italy and her team investigated yawning in two species of lemur from the Ankoba forest in southern Madagascar.


They weren’t surprised to find that lemurs yawned more when they were sleepy and that females and males yawned equally often.

But they also found that yawning was related to a lemur’s anxiety levels. For example, both species yawned more frequently shortly after being threatened by a predator.

Although stressful situations have been linked to yawning in some non-primates, the behaviour is usually a delayed response, observed about 30 minutes afterwards in lab studies. It’s thought to happen when an animal starts to relax.

Palagi and her team think the same could be true of lemurs, despite being much more immediate. Outside the lab, wild animals tend to recover more quickly, and predator threat is a familiar situation from which they have a chance to escape.

Yawning, which has been observed in animals from chimps to birds, seems to have various triggers. In elephants, it’s thought to be a tactic to cool down their brain while in budgies it may be a sign of empathy.

In humans, it was found to raise levels of cortisol, a hormone released in response to stress to make us more alert.

Journal reference: American Journal of Primatology, DOI: 10.1002/ajp.22459