HOW DO ANIMALS GLIDE IN THEIR NATURAL HABITAT? A HOLISTIC APPROACH USING THE FLYING LIZARD DRACO DUSSUMIERI

Gliding is a common form of aerial locomotion used by a diverse set of animals to perform behaviors essential for their survival. Behaviors like foraging, avoiding predators, seeking mates, and/or territorial aggression are influenced by selective pressures that can lead to differences in glide performance. Furthermore, the glide performance is dictated by the physics of the animal’s morphology and the environment in which it is performed. To understand the complex interplay between the animal’s morphology, behavior, and the environment and how it shapes glide performance, I ask an overarching question, how do animals glide in their natural habitat? I answer this question using a non-invasive motion capture technique in the natural habitat of the flying lizard Draco dussumieri. In Chapter 2, I describe in detail the gliding aerodynamics and the performance envelope used by Draco. In doing so, I discover a potential aerodynamic strategy that maximizes glide performance in terms of distance traveled and height lost. Chapter 3 extends the kinematic and aerodynamic analysis to an individual level looking at the influence of sex and body size on gliding performance. It shows the expected detrimental effects of isometric scaling of body size on aerodynamics but reveals compensatory changes in glide behavior to account for larger body size. Furthermore, I also show subtle glide performance differences within and among sexes, suggesting influences of selective pressure and ontogeny. Finally, I describe how gliding is actually implemented in the natural habitat. In Chapter 4, I focus on the sensory and environmental context looking at how Draco account for spatial complexity and tune their glide execution to reach their desired target. In doing so, I show that Draco primarily rely on vision to gather environmental information and use a path planning strategy to navigate their spatially cluttered environment. Overall, my findings provide the first holistic analysis of gliding showing how various intrinsic (sex, size, behavior) and extrinsic (environment) factors influence glide execution and performance. It presents a more biologically relevant picture of gliding than most studies conducted thus far and emphasizes the importance of observing behavior in the animal’s natural habitat.Doctor of Philosoph