Synchronised Wildebeest Calving

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The annual birth pulse on the short-grass plains, in which the large majority of pregnant females calve inside a window of roughly three weeks between late January and mid-March. Popular accounts put the total at 400,000 to 500,000 calves; the figure is a derivation from population size and pregnancy rate rather than a counted number, and it varies with which census estimate is used. Synchrony is reinforced behaviourally: females exposed to playback of male rutting calls were more than three times more synchronous in expected time to mating than isolated controls (Berry et al., Scientific Reports 2018). The functional explanation usually given is predator satiation — so many calves appear at once that resident predators cannot take a large fraction of them.