Hyenas engage in plenty of play-fighting, and they have a way to let fellow hyenas know when an attack is part of a game: they bob their heads and make clear facial expressions.
Known for their particularly vicious fights and a strong dominance order in their clans, hyenas also frequently spend long periods of time play-fighting with each other. But they always make sure the message is clear that they don’t intend to be aggressive, especially if the fight is uneven, says at the University of Pisa, Italy.
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“It seems that if I want to play hard, I need signals to clarify that I am not attacking you, and that this is only play,” says Palagi.
Palagi and her colleagues used multiple video cameras, including some motion-activated ones, to gather 38 hours of play-fighting footage among 24 wild spotted hyenas (Crocuta crocuta) at the in Limpopo, South Africa.
Their analyses revealed that adults will regularly play-fight with other adults or with juveniles – while juveniles will also play-fight with each other – and that they consistently use subtle body language to communicate with each other that the fight isn’t serious, says Palagi.
That body language involves mostly a relaxed, open mouth – similar to that previously reported in dogs, bears, seals and chimpanzees when they play-fight – but also a characteristic head bobbing, somewhat reminiscent of a . Hyenas bob their heads during other gentle interactions with each other as well, such as before mating or affiliative behaviours like muzzle rubbing. But the relaxed, open mouth is used specifically during playtime, says Palagi.
Surprisingly, the more unbalanced the play-fight is – meaning when one hyena was clearly “winning” and the other “losing” – the longer the play session lasts, says Palagi. In most animals, when the play-fight gets too uneven, the players either stop the fight or it escalates into true fighting. But hyenas seem to have an alternative approach. “This is completely different from any other species,” she says. “It’s incredible.”
That might be to do with their good communication, she says. The team’s analyses revealed that the more one hyena was winning over another hyena, the more the hyenas showed the relaxed, open-mouth expression. And when adults started play-fighting with juveniles, they also used this facial expression more, although youngsters tended to bob their heads more when play-fighting with each other.
Regardless of the body language they choose to instigate play, however, the hyenas always ensure their potential playmate is looking at them before making it. “They’re not just relying on vocalisations,” says Palagi. “Visual cues like facial expressions and body postures are important.”
Journal references: Current Zoology, Ěý˛ą˛Ô»ĺ Animal Behaviour,
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