Do mixed-species groups travel as one? An investigation on large African herbivores monitored using animal-borne video collars

Abstract

Although prey foraging in mixed-species groups benefit from a reduced risk of predation, whether heterospecific groupmates move together in the landscape, and more generally to what extent mixed-species groups remain cohesive over time and space, remains unknown. Here, we used GPS collars with video cameras to investigate the movements of plains zebras (Equus quagga) in mixed-species groups. Blue wildebeest (Connochaetes taurinus), impalas (Aepyceros melampus), and giraffes (Giraffa camelopardalis) commonly form mixed-species groups with zebras in savanna ecosystems. We found that zebras adjust their movement decisions solely on the basis of the presence of giraffes, being more likely to move in zebra-giraffe herds, and this was correlated with a higher cohesion of such groups. Additionally, zebras moving with giraffes spent more time grazing, suggesting that zebras benefit from foraging in the proximity of giraffes. Our results provide new insights into animal movements in mixed-species groups, contributing to a better consideration of mutualism in movement ecology.