Résumé
Tropical forests show high spatiotemporal seasonal variation in food availability, especially for fruits. To forage efficiently, frugivorous primates are expected to have higher spatiotemporal knowledge of food availability than folivorous primates. Here, we compiled published and new evidence to shed light on the foraging strategies and the underpinning cognition in the seasonally frugivorous western gorilla (G. gorilla) in response to seasonal changes in resources (high- and low-fruit seasons). Specifically, we assessed how western gorillas decide where to feed (movement heuristic and spatial knowledge), how to move (e.g., movement speed and straightness), and when to go (temporal knowledge) and come back to feeding sites (recursion pattern) when feeding mostly on fruits or leaves. Based on GPS tracks continuously recorded on three habituated groups in Central African Republic (May 2016 to November 2017), we found that western gorillas rely on spatiotemporal knowledge to decide where to go and when in both dietary seasons. Space-use patterns (daily path length and weekly range) were larger during the high-fruit season because of changes in food spatial distribution. However, the foraging strategies barely changed with seasons in terms of speed, straightness, and recursion patterns. Our results highlight how spatiotemporal cognition may buffer the effects of changes in food availability in seasonal frugivorous species. Given their role in seed dispersal, characterizing the cognition underlying tropical frugivore movements may provide insights into understanding large-scale ecological processes underpinning tropical forest regeneration and dynamics.