Spatiotemporal antipredator responses of capybaras in areas with and without apex predators

Abstract

Predation risk can drive spatial and temporal adjustments in prey behavior. This study investigates the spatiotemporal responses of capybaras (Hydrochoerus hydrochaeris) to predation pressure in two areas: the Pantanal in Brazil, where their main predators - jaguars (Panthera onca) and pumas (Puma concolor)- are present, and the Iberá Wetlands in Argentina, where these apex predators were absent until jaguars were reintroduced in 2021. Linear models and circular statistics were used to test whether the capybara’s gregarious behavior, distance to water (safe zones), and activity patterns differ between sites before jaguar reintroduction in Iberá, while controlling for temperature and lunar cycles. Capybaras in Pantanal displayed high group cohesion, foraged close to water, and limited their activity to daylight hours, regardless of temperature or moonlight. Conversely, Iberá capybaras exhibited flexible spatial and temporal patterns, foraging at varying distances from water and adjusting activity according to environmental conditions, mainly temperature. These results suggest that capybaras coexisting with pumas and jaguars perceive predation risk in space and time, adapting their behaviors accordingly. These findings emphasize the potential role of predation risk in shaping prey behavior and suggest that the reintroduction of apex predators can restore ecological processes like trophic cascades affecting not only prey populations but also entire biological communities.