Meeting Abstract

71.4  Wednesday, Jan. 6  Kinematics of a fast bat: Changes in wing kinematics with flight speed in the migratory bat (Tadarida brasiliensis) HRISTOV, N.I.*; RISKIN, D.K.; HUBEL, T.Y.; ALLEN, L.C.; BREUER, K.S.; SWARTZ, S.M.; Brown University, Providence, RI nickolay_hristov@brown.edu

Bats are unique among mammals in their ability to fly. Although flight in bats originated from a single common ancestor, the primitive flight apparatus has diversified over evolutionary time to match the tremendous radiation of bats. However, to date, there is little knowledge about how bats of different sizes and wing shapes are capable of producing the aerodynamic forces necessary for flight under different flight conditions. Understanding the mechanism of flight in bats requires accurate 3D kinematic descriptions of the wings of bats with diverse flight strategies. In this study we present a detailed description of the wing kinematics of a bat specialized for fast flight, flying at a range of speeds. Brazilian free-tailed bats (Tadarida brasiliensis) were trained to fly in a wind tunnel at speeds between 3.5 and 7.5 m/s. To reconstruct 3D motion of anatomical landmarks, markers were placed on the body and wings of bats and their motion was recorded with multiple high-speed digital video cameras. Kinematic parameters calculated from these motions show striking differences in the overall pattern of wing movement in this species compared to other species of bats. Throughout the wingbeat cycle, T. brasiliensis maintained a relatively flat wing surface with minimal wing bending. Furthermore, as flight speed increased, there was little change in the pattern of wing motion, instead, bats changed the shape of their wings by modifying wing extension, camber and angle of attack. This study demonstrates that the dynamic shape of the wing in flight is very different from its static morphology and the use of simple models to represent the diversity of flight strategies among bats is insufficient to capture their diversity.