Climbing Performance of Boas (boa imperator) Raised on Two Feeding Regimes

Kryzsko Commons Ballroom, Winona, Minnesota

Arboreality imposes significant challenges to an animal's morphology and physiology. Within snakes, a suite of characteristics including specialized locomotor strategies, reduced body mass to length ratio and laterally compressed shape are presumed to be evolutionary adaptations to an arboreal lifestyle. However, few studies have experimentally tested climbing performance of snakes that exhibit "arboreally adapted morphology" and "terrestrially adapted morphology." We studied the climbing performance of two groups of full-sibling boas that were reared on two different feeding regimes that resulted in divergent morphology. Half of the boas were frequently fed, and half were infrequently fed, all snakes received the same relative mass of prey. Using a vertically hung tensioned rope, we measured the following variables related to climbing performance: climbing speed, duration of resting that resulted from cessation of ascent, and slipping. Our results indicate that it is not only evolutionary forces that shape arboreal morphology and physiology, but also point to the significance of phenotypic plasticity.