Energetics-informed behavioral states reveal the drive to kill in African leopards

Abstract

The drive to kill prey is central to understanding the population viability and ecological effects of large carnivores. This drive is modulated by behaviorally determined energetic expenditures, yet current methods of estimating the energetics of terrestrial carnivores are too coarse to inform the fine time scale behavioral decisions that incur the energetic costs leading to predation. Here, we use combined GPS and accelerometer collars calibrated to measure energetic outputs at scales of seconds to months on African leopards in Kenya. Fine-scale data on energetic expenditures and movement allowed us to determine energetically informed behavioral states that accurately identified when animals killed or scavenged prey, and allowed us to visualize novel details concerning the cryptic natural history of these predators. Our results revealed large variation in daily field metabolic rate ranging from 11,000 to 32,000 kJ depending on the animal and the specific behaviors undertaken. Leopards expended 47,470 kJ between kill events on average, but this was increased if meal size from the previous kill was large. Our methods also allowed us to estimate the energetic costs of dispersal, territorial patrol, and parental care, considered important factors in overall energetic balance and thus the drive to kill. Based on this approach, we demonstrate how the cycle of behavior, energetic expenditure, and predatory drive underlies population trajectories of large carnivores as well as their direct and indirect effects on ecosystems.