Meeting Abstract

112.1  Tuesday, Jan. 7 10:15  Incline, peg height, peg shape and body shape have interactive effects on the arboreal locomotion of snakes NEWMAN, S.J.*; BERNS, H.M.; ZENTKOVITCH, M.M; JAYNE, B.C.; Univ. of Cincinnati newmansv@mail.uc.edu

The height and shape of ledge-like structures in the bark of trees vary substantially. Several species of arboreal snakes have convergently evolved the ability to make a ventrolateral keel, which seems well suited for catching on ledge-like structures. However, the effects of these aspects of environmental structure and morphology on arboreal locomotion are poorly understood. Hence, we used cylindrical surfaces with different inclines (N=5) and heights (N=5) and shapes (N=2) of pegs to test how certain attributes of bark texture affect the locomotion of snakes. Of the three species in our study, both corn snakes and brown tree snakes formed a conspicuous ventrolateral keel, but boa constrictors did not. Unlike the other two species, brown tree snakes performed lateral undulation on pegs that were only 1 mm high on all inclines ranging from horizontal to vertical as well as up a 60 deg slope on the underside of a cylinder that had 2 mm high, wedge-shaped pegs. Brown tree snakes were faster and used lateral undulation on more surfaces than the other two species. Corn snakes often performed lateral undulation when pegs were 2 mm but not 1mm high, and steep surfaces with short pegs where often impassable for this species. Boa constrictors used concertina locomotion more often than the other study species, and they usually did not perform lateral undulation until the height of pegs exceeded 2 mm. Some tradeoffs between proficient concertina and undulatory locomotion occurred between corn snakes and the stouter boa constrictors. By contrast, every aspect of the arboreal locomotor performance that has been documented for brown tree snakes appears to equal or exceed those of the other two more muscular study species, which also regularly climb trees.