The selection pressures that arise from capturing prey and avoiding predators are some of the strongest biotic forces shaping animal form and function. Examining how performance (i.e., athletic ability) affects the outcomes of encounters between free‐ranging predators and prey is essential for understanding the determinants of predation success rates and broad scale predator–prey dynamics, but quantifying these encounters in natural situations is logistically challenging. The goal of our study was to examine how various metrics of predator/prey performance determine predation success by studying natural predator–prey interactions in the field with minimal manipulation of the study subjects. We used high‐speed video recordings of free‐ranging sidewinder rattlesnakes (predator, Crotalus cerastes) and desert kangaroo rats (prey, Dipodomys deserti) to study how performance at various stages of their encounters alters the outcome of their interactions. We found that predation success depends on (a) whether the rattlesnake struck accurately, (b) if the rattlesnake strike was accurate, the reaction time and escape manoeuvres of the kangaroo rat, and (c) if the kangaroo rat was bitten, the ability of the kangaroo rat to use defensive manoeuvres to avoid subjugation by the snake. The results of our study suggest that the role of performance in predator–prey interactions is complex, and the determinants of predation success are altered by both predator and prey at multiple stages of an interaction in ways that may not be apparent in many experimental contexts. A http://onlinelibrary.wiley.com/doi/10.1111/1365-2435.13318/suppinfo is available for this article.

No abstract

Predators often employ a complex series of behaviors to overcome antipredator defenses and effectively capture prey. Although hunting behaviors can improve with age and experience, many precocial species are necessarily effective predators from birth. Additionally, many predators experience innate ontogenetic shifts in predatory strategies as they grow, allowing them to adapt to prey more appropriate for their increased size and energetic needs. Understanding how the relative roles of innate age-specific adaptation and learning have evolved requires information on how predation behavior develops in situ, in free-ranging predators. However, most of the research on the ontogeny of predation behavior is based on laboratory studies of captive animals, largely due to the difficulty of following newborn individuals in nature. Here, we take advantage of the unique tracks left by juveniles of a precocial viperid, the sidewinder rattlesnake (Crotalus cerastes), which we used to follow free-ranging snakes in the field. We recorded details of their ambush hunting behavior, and compared the behaviors of these juveniles to adult snakes that we monitored in the field via radio telemetry. Although juvenile and adult behaviors were similar in most respects, we did find that adults chose more effective ambush sites, which may be due to their increased experience. We also found that juveniles (but typically not adults) perform periodic tail undulations while in ambush, and that juveniles displayed slightly different activity cycles. Both of these latter differences are likely the result of age-specific adaptations for juveniles' greater reliance on lizards versus small mammals as prey. We also compared the general predatory behavior of sidewinders to that of other species in the genus Crotalus. These findings will provide important baseline field information for more detailed empirical research on the ontogeny of predation behavior in precocial vertebrates.

Predation plays a central role in the lives of most organisms. Predators must find and subdue prey to survive and reproduce, whereas prey must avoid predators to do the same. The resultant antagonistic coevolution often leads to extreme adaptations in both parties. Few examples capture the imagination like a rapid strike from a venomous snake. However, almost nothing is known about strike performance of viperid snakes under natural conditions. We obtained high-speed (500 fps) three-dimensional video in the field (at night using infrared lights) of Mohave rattlesnakes (Crotalus scutulatus) attempting to capture Merriam’s kangaroo rats (Dipodomys merriami). Strikes occurred from a range of distances (4.6 to 20.6 cm), and rattlesnake performance was highly variable. Missed capture attempts resulted from both rapid escape maneuvers and poor strike accuracy. Maximum velocity and acceleration of some rattlesnake strikes fell within the range of reported laboratory values, but some far exceeded most observations. Thus, quantifying rapid predator-prey interactions in the wild will propel our understanding of animal performance.