Lion proximity, not moon phase, affects the nocturnal movement behaviour of zebra and wildebeest

Abstract Moon phase affects nocturnal activity patterns in mammals. Among ungulates, a number of studies have found animals to be more active over full moon nights. This may be because increased luminosity provides increased opportunity to forage and/or increased ability to detect predators; known as the visual acuity hypothesis. Here, we use GPS ‐derived movement data to test for the influence of moon phase on plains zebra Equus quagga and blue wildebeest Connochaetes taurinus activity in Kruger National Park, South Africa. We compare animal movement (rate and displacement) over full and new moon nights, and consider the effect of lion proximity. We found that lion proximity largely determined the nocturnal movements of zebra and wildebeest, not moon phase. When lions were >1 km away, there was no difference in the nocturnal movement activity of prey animals over full and new moon conditions, contradicting previous findings. When lions were within 1 km of these animals, however, the movement of zebra and wildebeest greatly increased over the new moon, the relatively dark period when lion were most likely hunting. Although we could not explicitly test for predator detection here, our findings suggest that the visual acuity hypothesis does not hold for zebra and wildebeest in Kruger National Park (KNP) given that there is no evidence for increased foraging activity over the full moon. The influence of moon phase on the nocturnal activity of African ungulates may be more complicated than anticipated, and we suggest that this cannot be estimated unless predator proximity is accounted for.