Hunting, scavenging, and kleptoparasitism: A fitness-maximising approach to predicting predator foraging strategy

Mammalian carnivores' foraging strategies include hunting, scavenging, and kleptoparasitism (stealing). Despite the prevalence of literature on predator-prey systems, the factors that result in the deployment of these strategies and their effects on predator-prey systems (and ecological communities) are well understood. In this study, we use an energetics-based computational model to investigate how a focal predator's interactions with potential prey and other predators constrain the use of these strategies. Our results predict the dependence of predator foraging strategy on predator energetics as well the body sizes of the focal predator, prey, and the 'victim' of stealing/scavenging. In particular, our results predict the boundaries of predator foraging strategies exceptionally well. By employing dimensional reduction, we are able to describe the phase transition from a state where the focal predator relies predominantly on hunting to a state where the focal predator largely relies on scavenging and stealing, by a reverse sigmoidal function. We verify these results using data from a large number of field observations. Our model can be easily extended to predict the prevalence of different strategies in real predator-prey assemblages as well as the effect of predators foraging in groups on the deployment of different predator foraging strategies.