A Functional Role for Bipedal Locomotion in Lizards

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A crucial aspect of the ecological morphology paradigm is the role of performance as the link between organismal traits and their fitness consequences in the environment. Behavior is also included in the paradigm as an additional link, especially when habitat variation is considered. Behavior serves to modulate, or potentially filter, performance variation, in direct and indirect ways. I will present data from studies examining the role of bipedal vs. quadrupedal locomotion in lizards. Bipedalism has been studied extensively, however the functional consequences and/or benefits of this behavior have remained elusive. I will show that some species of lizards modulate their use of bipedalism, and the use of the posture provides an advantage when crossing an obstacle. Furthermore, lizards employ a bipedal posture in a predictable manner as they encounter obstacles. Hence growing evidence supports a functional role for bipedal running behavior, and regardless of its origin, provides a mechanism for selection to maintain, or potentially enhance, its use in some lineages. In particular, this would be true for animals whose microhabitat might constrain performance traits such as maximal sprint speed. Instead acceleration, agility, or their combination, may be key traits correlated to fitness, and locomotor behavior may be a key selective filter.


International Congress of Vertebrate Morphology (ICVM)


Washington, DC