| Gliding has evolved numerous times in mammals, however little is understood about the selective pressures that drove its origins. Multiple working hypotheses have been put forth to explain why gliding has evolved. These include the need to escape predators, to forage over wider areas, to minimize cost of transport, or as a result of habitat structure. Little systematic data on the gliding behavior of free-ranging animals has been collected. This dissertation focuses on gliding mammals from two distinct lineages, the colugo (Galeopterus variegatus) and southern flying squirrel ( Glaucomys volans). This study uses custom designed animal-borne data loggers to collect systematic data on the locomotor behavior of these animals within both ecological and biomechanical contexts.;Results suggest that free-ranging colugos spend very little time engaged in locomotor behaviors. Furthermore, most glides recorded are much shorter than the maximum achievable distance. In addition, the high cost of vertical climbing to initiate glides results in higher locomotor costs for gliding locomotion that would be predicted for animals of similar size running the same horizontal distance. This evidence coupled with the observation that colugos spend such a small fraction of their daily time budget engaged in locomotor activity suggests that factors other than maximizing locomotor economy or total distance traveled have played a greater role in the origins of gliding.;A high level of aerodynamic control is also required for gliding to control the trajectory and land safely in the desired location. Results suggest that during glides, colugos generate more force than is required to offset body weight to glide at constant speed. In doing so, they are able to reduce velocity in the vertical or horizontal dimensions continuously throughout the glide. A complex landing maneuver, resulting from symmetric limb movements, is initiated just prior to landing further reducing velocity, allowing animals to alight safely on the landing tree. This work shows that both ecological pressures and biomechanical constraints shape the gliding behavior of mammals. |
