Meeting Abstract

P2.203  Thursday, Jan. 5  Kinematics and Performance of Arboreal Limbless Locomotion in Boiga irregularis BAUM, J.T.*; JAYNE, B.C.; Univ. of Cincinnati, Cincinnati; Univ. of Cincinnati, Cincinnati

In arboreal habitats branch orientation and spacing vary considerably. Branches and objects such as pegs provide discrete locations for snakes to generate propulsive forces when they use lateral undulation. However, the consequences of branch spacing for locomotor performance of snakes and nearly all animals are poorly understood. Hence, we determined maximal speeds and kinematics of an arboreal snake (Boiga irregularis) crawling on cylindrical perches (diameter = 1.6 cm) with horizontal and vertical orientations and five different peg spacings (10, 20, 30, 40, and 80 cm). All of the snakes used lateral undulation on all of the surfaces, and peg spacing, perch orientation, and their two-way interaction all had significant effects on all measures of performance and kinematics. For the horizontal perches, the mean speeds at the smallest and largest peg spacing were approximately 10% snout-vent length/sec, and the greatest mean speed was for the 40 cm spacing (16% SVL/sec). Unlike snakes on the horizontal surfaces, the mean speeds for the vertical surface varied little with peg spacing and were uniformly slow (range 5-6% SVL/sec). For both perch orientations the number of pegs touched by the snake decreased as peg spacing increased, and while touching only one peg the snakes crawled with apparent ease and steady speed. In addition, the snakes crawled vertically using one peg as quickly and easily as they did using 2-10 pegs. Pegs on a horizontal cylinder are probably important for both balance and propulsion of snakes, whereas pegs protruding from vertical cylinders probably resemble those protruding from horizontal planar surfaces by being used almost exclusively for propulsion.