Long-distance communication and fission-fusion dynamics in spotted hyenas

Spotted hyenas live in fission-fusion societies, where clan members move alone or in small subgroups that split and merge over time. Despite being widely dispersed over several kilometers, hyenas can come together rapidly for collective defense of prey items against lions, or in conflicts with neighboring clans, via long-distance recruitment calls known as "whoops".

We aim to investigate how communication and coordination interact in these dispersed animal societies, using collars that simultaneously track the positions, vocalizations, and activity patterns of hyenas within a clan. We are interested in how information is transmitted over long distances in these groups, how hyenas decide whether or not to respond to recruitment calls, and how such communication impacts their long-term movement dynamics.

This project is in collaboration with Frants Jensen, Andrew Gersick, Mark JohnsonKay Holekamp, and the MSU-Mara Hyena Project. In a pilot experiment, we recently fitted 5 adult female hyenas with collars that record their positions once per second using GPS, their vocalizations using an audio recorder, and their activities using an accelerometer. We are also performing playback experiments to test whether hyenas respond more strongly to calls from individuals in their own clan, as compared to calls from members of a neighboring clan or calls from strangers. In future work, we will fit tracking collars to an entire clan of hyenas to observe their behavior simultaneously, allowing us to address how information flows within these distributed animal societies.

Hyena ranging patterns

 

Visualization of two days of GPS data from five collared hyenas (each color represents a different individual).

Playback experiments

 

We are performing targeted playback experiments to assess hyenas' responses to recruitment calls. Here, a hyena ("Bora") hears a whoop call from one of her clan-mates and responds by running in the direction that the call came from. Note that a second hyena ("Fay") also responds - you can see her running in from the right hand side of the screen near the end of this clip.

Long-term responses to recruitment calls

This visualization shows the same playback experiment as above, viewed from the perspective of our GPS data. The box shows the location of the speaker where the whoop calls are played from (it turns yellow when the calls start). Blue dot shows the focal hyena we were watching in the above video ("Bora"), and the orange dot shows the second hyena ("Fay") who was sitting nearby and also responded. While Bora soon returns to her original resting location, Fay continues on toward the clan border after the playback. Two other hyenas (red and pink dots) located farther away are also shown.