Watching a group of lions yawn may seem like nothing more than big, lazy cats acting sleepy, but new research suggests that these yawns may be subtly communicating some important social cues. Yawning is not only contagious among lions, but it appears to help the predators synchronize their movements, researchers report in the journal Animal Behavior.
The discovery was partially made by chance, says Elisabetta Palagi, an ethologist at the University of Pisa in Italy. While studying play behavior in spotted hyenas in South Africa, she and colleagues often had the opportunity to watch lions at the same time. And she quickly noticed that lions yawn quite frequently, concentrating these yawns in short time periods, according to the German News Agency. Yawning is ubiquitous among vertebrates, possibly boosting blood flow to the skull, cooling the brain, and aiding alertness, especially when transitioning in and out of rest, the Science News website reported. In many species — like humans, monkeys, and even parakeets— yawners can infect onlookers with their "yawn contagion," leading onlookers to yawn shortly afterward.
Over four months in 2019, the researchers closely monitored 19 lions at the Greater Makalali Private Game Reserve. The team found that lions that saw another member of the pride yawn were about 139 times as likely to yawn themselves within the next three minutes. But the yawn contagion didn't stop there. Lions that caught a yawn from another lion were 11 times as likely to mirror the movements of the original yawner than those that hadn't. This motor synchrony" involved one lion yawning, then another yawning, then the first getting up and walking around or laying back down and the other doing the same thing.
In lions, contagious yawning might be important for maintaining social cohesion, Palagi says. Yawns that help lions harmonize their group movements could help get the pride all on the same page, crucial behavior for an animal that hunts and rears offspring cooperatively. Palagi notes that yawning often marks a shift between different physiological or emotional states. So, a yawn could be a good way for an individual in a social species to communicate to group mates that it is experiencing some kind of internal change.