Hyenas, often perceived as solitary creatures, continue to surprise researchers with their distinctive social lives. From fleeting encounters to long-term bonds, these predators exhibit a wide range of social interactions. In this photo, three hyenas join together to attack a lioness.
American biologist Kay Holekamp from Michigan State University is having a hard time with African hyenas. Originally planned as a short-term dissertation project, her research on hyenas in Kenya has evolved into a 35-year-long captivating project. Together with colleagues, she published a report in 2017 that revealed that hyenas form alliances against their competitor, the lion, not only around fresh prey meat. Interestingly, hyenas band together even when the obvious benefit seems to be missing. Zoologists refer to this form of cooperative behavior as mob formation.
In their new study, Holekamp and her team examined what motivation might lie behind this cooperative mob formation and under what conditions it arises. As part of their investigations lasting several years, they were able to observe around a thousand such alliances, which were mostly very short-lived. “These interactions often happen extremely quickly, there are a lot of hyenas and lions present and most of them move quite quickly,” says Holekamp. “This makes it very difficult to capture what is happening so precisely that we can include it in our analyses.”
The evaluation showed: Hyenas are more likely to form groups when there are no male lions nearby, which are particularly dangerous for the attacking hyenas. Around a quarter of hyena deaths are attributable to lions, the team reports. In addition, long-standing social contacts between the hyenas play an important role in cooperation. “The connections formed over time make the difference,” explains Holekamp’s colleague Kenna Lehmann. These relationships overcome social barriers between hyenas and promote alliances when hunting prey.
Scientists are fascinated by the findings about the social behavior of these mammals. “Finding these results was really exciting, but I think the fun of science is that you answer one question and immediately have 50 more,” says Tracy Montgomery, who now conducts research at the Max Planck Institute for Behavioral Biology.