Escape behaviour varies with distance from safe refuge

Abstract

Abstract Locomotor performance and behaviour are important for escape from predators, yet the intersection of these strategies is poorly studied. Escape behaviour is context dependent, and optimal escape theory predicts that animals that are farther from a safe refuge will generally use faster running speeds but might choose to use more variable escape paths. We studied locomotor performance and behaviour of six-lined racerunner lizards (Aspidoscelis sexlineata) escaping on natural surface runways that were varied experimentally to be either 5 or 10 m from a safe refuge. On the 5 m runway, lizards usually escaped directly towards the refuge, attained a slower maximal running speed (3.2 m s−1) at ~3 m from the start, and reached the target refuge in most of the trials (80%). On the 10 m runway, lizards used more variable behaviour, including reversals and turns, attained a faster maximal running speed (3.7 m s−1) at ~6 m from the start, and reached the final refuge in only 43% of trials. Free-ranging racerunners were rarely > 5 m from their nearest refuge and used escape paths that were typically < 5 m. Our findings align with predictions from optimal escape theory, in that the perceived risk of a predator–prey encounter can drive adjustments in locomotor behaviour and performance. Additionally, we show that the escape behaviour of free-ranging lizards closely matches their escape behaviour and performance during controlled escape trials.