This is a guest post from Eli Strauss, a PhD student in the Zoology department at Michigan State University. He is interested in the evolution of sociality and the causes and consequences of variation in social system structure. Eli plans to compare the social behavior of hyenas in and around Harar with hyenas located in the Masai Mara Game Reserve in southern Kenya.
In my opinion, the social system of the spotted hyena is one of the most interesting attributes of the species. They live in clans ranging from 3 to over 120 individuals, and every hyena has a unique rank inherited from its mother. Despite the sometimes massive clan sizes, hyenas usually congregate in subgroups and the whole clan is almost never together all at once. Hyenas recognize and know the ranks of all other individuals in the clan, and will alter their behavior depending on who is nearby. A hyena’s rank is a huge determinant of the sort of life it might live, because rank determines access to food and other coveted resources. If you have ever seen hyenas interacting with each other, you probably remember lots of chasing, giggling, and growling. These are parts of everyday hyena life, where higher-ranking individuals behave aggressively towards lower-ranking hyenas, sometimes to take food from them and sometimes just to remind them who is boss.
After spending two weeks with the Harar hyenas, however, it has come to my attention that there may be a factor more important than rank in determining the success of these hyenas: boldness around humans. This is particularly pronounced at the hyena-feeding site, where the hyena that is most comfortable approaching and taking food from Abbas ends up eating the most. In fact some hyenas, such as Marcus’ friend Willi or the new boldest-hyena-in-town Willi II, use their boldness to protect themselves from the meddling of higher ranked hyenas. These hyenas will approach Abbas from the side closest to the spectators, placing them in an area that most (higher ranking) hyenas aren’t comfortable going.
The boldest of them all: Willi II’s extreme comfort with people lets him enjoy the bulk of the food while higher rankers are too nervous to do anything but sit and watch.
Of course, boldness isn’t only important at the feeding site. It also plays a role in who gets access to food left on the streets and the dumpsters of Jogol, as well as who gets first crack at the garbage as it is delivered to the dump in the mornings. It’s hard to say exactly how influential boldness is on the life and health of Harar hyenas, but it is certainly an interesting question. Who knows, maybe, when it comes to determining the success of Harar hyenas, boldness outranks rank.