Variation in resting strategies across trophic levels and habitats in mammals
Physical and Biological Sciences
Ecology and Evolutionary Biology
Mammals must balance activity (foraging, finding a mate) with sleep in order to minimize predation and/or competition. However, factors influencing sleeping strategies, and the degree to which resting strategies are driven by the activities of predators and/or prey, remain largely unknown. Despite the potentially large survival consequences of sleeping in a suboptimal time or place, behavioral ecology research tends to focus on the active portions of species' daily patterns. Our goal was to examine how mammalian sleeping strategies varied with position in the food web, body size, and habitat. We reviewed 127 publications on mammalian sleeping and classified strategies into three categories: social (e.g., sleep in groups), temporal (e.g., sleep during the day), or spatial (e.g., sleep in burrows). Temporal strategies were the most common (54% of all cases), but body size and food-web position strongly influenced the animal’s sleeping strategy. Specifically, small mammals or mammals that were lower on the food chain (e.g rabbits or mice) used mainly spatial or social strategies, whereas larger animals or animals that were higher on the food chain (e.g. lions or bears) use mostly temporal strategies. Human activity strongly altered sleeping strategies, most notably the sleep-timing of top predators. These human-caused changes in sleeping behavior ripple up and down the food chain, and negatively impact multiple levels of the food web.
