COS 53-5
Male rutting calls synchronize reproduction in Serengeti wildebeest

Tuesday, August 11, 2015: 2:50 PM
341, Baltimore Convention Center
Justin M. Calabrese, Conservation Ecology Center, Smithsonian Conservation Biology Institute at the National Zoological Park, Front Royal, VA
Allison Moss Clay, Center for Species Survival, Smithsonian Conservation Biology Institute
Richard D. Estes, Center for Species Survival, Smithsonian Conservation Biology Institute
Katerina V. Thompson, College of Computer, Mathematical, and Physical Sciences, University of Maryland
Steven L. Monfort, Smithsonian Conservation Biology InstituteInstitution, Front Royal, VA

Tightly synchronized calving in vast herds of Serengeti wildebeest overwhelms predators and dramatically increases calf survivorship, but despite decades of study, the proximate synchronizing mechanism remains unknown. It has long been hypothesized that mass male rutting calls act to induce female ovulation and thus synchronize reproduction in large wildebeest herds, but this hypothesis has yet to be conclusively tested. Here, we test the rutting call hypothesis by combining a season-long field experiment with stochastic process models.


We show that females isolated from all male stimuli were 14.3 (3.4, 39.2) times more variable, and thus significantly less synchronous, in their time to estrous relative to an experimental group exposed to recordings of male rutting vocalizations. Additionally, calving distributions predicted from the playback treatment could account for the synchrony observed in independent calving data from the Serengeti, while predictions based on the control group could not. Taken together, our results reveal that male rutting vocalizations alone can account for most of the calving synchrony observed in the immense herds of the iconic Serengeti wildebeest.