Notes From Kenya: MSU Hyena Research: No work and all play

While on our morning observation yesterday, Benson and I had the joy of finding 5 hyenas on top of a very dead, very putrid vulture. While looking through our binoculars to ensure no subtle behaviors were missed, we were simultaneously trying (and failing) to cover our noses from the horrible smell. However, the hyenas didn’t seem to mind the smell, in fact they seemed to enjoy it. At first, it was difficult to tell if the hyenas had acquired the bird with intent to eat it, or if they were merely playing with it. Behaviors that we would typically classify as aggressions (e.g. snaps, bites, chases, and lunges) appeared to be being exhibited, but the recipient of the behavior never exhibited the submissive behaviors typically seen after an aggression (e.g. laying ears against the head, grinning, giggling, defensive parrying). With hyenas with ranks all across the board, it was quite odd at first to not see any submissive behaviors being displayed from the lower ranking individuals. In fact, it appeared that all five individuals (Arby’s, Athi, Complex, Eowyn, and Richard Hatch) were all excitedly vying for their turn to roll in the carcass and cover themselves in the smell of dead bird. After witnessing a few interactions that we initially thought were aggressive in nature, we were able to discern that these hyenas were indeed playing with not only each other but also the vulture carcass.

Play behavior is commonly seen during the development of mammalian species and is typically seen in juveniles. Adult social play has been observed in multiple mammalian species, including spotted hyenas (Estes, 2012). Play behaviors are often high energy – e.g. running or chasing, and overall result in a net loss of energy for the individual(s) involved. So why waste the energy, especially in this case where there was a seemingly perfect energy source present? Since it’s so initially costly, it’s thought that play behaviors function to fine tune animals to situations they will experience later in life (Nunes et al. 2002). In a gregarious animal like the spotted hyena, social play, like we saw yesterday, probably functions to establish relationships with other individuals in the social group (Holmes 1994, 1995). It’s also thought that certain play behaviors allow the players to strengthen their motor skills (Nunes et al. 2002) so that they’re better equipped to deal with situations in which those behaviors could help the individual defend themselves, territory, or a kill (in the case of hyenas). As for the function of rolling in a dead bird, it’s possible we’ll ever know. Maybe the smell is just as enticing to hyenas as it is revolting to us!