VANHOOYDONCK, BIEKE*; JIMENEZ, MARTIN; IRSCHICK, DUNCAN J.: Effects of surface diameter on acceleration in arboreal lizards

Few studies have examined how environmental factors affect acceleration, and none have examined the effects of surface diameter on acceleration. Many animal species occur in habitats that vary in surface dimensions, particularly arboreal lizards. We studied the effects of surface diameter on acceleration in the arboreal lizard, Anolis sagrei. Two surface diameters were employed (0.5 cm and 6.5 cm), and acceleration and other kinematic variables were examined over the first five strides of locomotion. Over the first five strides, speed and stride length increased significantly, and these quantities also increased on the broad surface diameter. Stride frequency was slightly greater on the broad surface, but the difference was not statistically significant. Both the angle of the trunk and the tail remained fairly constant across different strides, and neither variable changed significantly with surface diameter. Acceleration was substantially lower (<50%) on the narrow surface, especially for the first several strides, after which differences were minimal. These data suggest that movement on narrow surfaces could significantly impair an organism’s ability to escape predators and capture prey.