Meeting Abstract
Many arboreal animals, from insects to vertebrates, use directed aerial descent (DAD) to avoid predation, locate mates or resources, and minimize deleterious impacts of a jump or fall. Such behaviors may have been an important precursor to the evolution of flight in vertebrates, and thus merits closer inspection even outside the context of the arboreal-cursorial debate. Here, we show that arboreal salamanders in the genus Aneides, some of which inhabit the crowns of the world’s tallest trees, use DAD during jumps despite having no apparent specialized aerodynamic control surfaces such as skin flaps. High-speed cameras were used (at 500 fps) to image arboreal salamanders from dorsal and lateral perspectives as they jumped from both raised platforms onto a landing pad, and into a vertical wind tunnel that simulated an extended descent. One non-arboreal plethodontid, Ensatina eschscholtzii, was studied in the vertical wind tunnel for direct comparison. E. eschscholtzii cannot jump, and its aerial performance varies greatly. Kinematic analysis revealed that all filmed salamanders were capable of mid-air stabilization, parachuting, and landing in a prone posture during jumps or falls. Aneides vagrans may also be capable of controlled maneuvers during extended descents as simulated in the vertical wind tunnel. Mid-air stabilization, parachuting, and maneuvers appear to be controlled by deliberate movements of the limbs, feet, and tail of these arboreal salamanders. This new example of DAD, the first to document the mechanics of aerial behavior in any salamander, suggests that the oft-cited long limbs and active tail of Aneides may serve in functions supplemental to climbing, and also is relevant to aerial hypotheses for the origin of flight in vertebrates.
