Meeting Abstract
100.5 Sunday, Jan. 6 Meal size affects the speed and modes of arboreal locomotion of the brown tree snake, Boiga irregularis MACKEY, T.L.*; JAYNE, B.C.; University of Cincinnati, Ohio; University of Cincinnati, Ohio mackey.93@gmail.com
Snakes commonly consume large prey and move in diverse environments including trees. Unlike many terrestrial environments, animals in trees commonly need to move on variable slopes and to balance on narrow, cylindrically shaped branches. Hence, we expected the arboreal locomotor performance of snakes to decrease substantially after consuming large meals that increased their weight and altered their distribution of mass. To test for this likely cost of consuming a large meal, we determined the maximal speed and mode of locomotion for 15 individuals of a highly arboreal snake species, Boiga irregularis, when they were unfed and within 48 hours of eating one or two mice, each of which averaged ~12% of the snake’s mass. The snakes crawled on cylindrical surfaces 24 mm in diameter, with and without pegs and with the long axis oriented horizontally or inclined 45 degrees. On all surfaces with pegs the snakes performed lateral undulation, and their maximum speed decreased significantly with increased meal size. When moving up the inclined cylinders without pegs, all snakes used concertina locomotion, and the maximum speeds after eating two mice were significantly slower than those of the other two treatments. On the horizontal cylinders without pegs, 87% of the unfed snakes had continuous sliding contact while performing lateral undulation, whereas after eating two mice 80% of the snakes periodically stopped and gripped the cylinder while performing concertina locomotion at speeds that were not significantly different from those of the unfed snakes. Thus, although large meals were often detrimental to speed, the behavioral response of switching the mode of locomotion (concertina) prevented slipping and long-axis rolling which commonly occur on smooth cylindrical surfaces.
