<p> A predator's attempt to capture prey involves energetic costs and risks of injuries. The need to avoid potentially severe consequences is one of the reasons why predation often requires high performance. I investigated the effects of different environmental conditions on predation performance in Florida kingsnakes. When pursuing prey in tight spaces (e.g., rodent tunnels) kingsnakes cannot coil around the prey as they do for constriction in open areas. Instead, they use pinioning, which involves using bends of the body to compress prey against a hard surface. </p><p> First, I analyzed the effects of tunnel width on pinioning performance, quantified as the peak pressure exerted on the prey. I tested three tunnel widths and hypothesized that the moderate width would elicit the highest performance. However, I found that the narrow tunnel led to the highest performance. The lowest pressures were exerted in the broad tunnel. These results suggest that as body length increases, the postures may become less stable and have less effective force transmission, leading to weaker pressure exertion. </p><p> Second, I investigated how darkness affects pinioning performance. I hypothesized that pinioning performance would differ in the dark compared to the light. I found that kingsnakes have significantly higher performance in the dark. The higher performance in the dark could be a means of behaviorally compensating for the snake's inability to use vision to assess the size and activity of the prey, and hence its risk of escape or injury to the snake in self-defense. </p><p> Together, these projects demonstrated that extrinsic factors (spatial constraints and darkness) and intrinsic factors (specific body parts involved) can affect an individual's behavior and performance. Hence, studying performance under different conditions is important for developing a detailed understanding of functional mechanisms as well as a broader understanding of the biology, ecology, and evolution of organisms.</p><p>