COS 53-5
Male rutting calls synchronize reproduction in Serengeti wildebeest
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.
Results/Conclusions
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.