Meeting Abstract

S5-2   09:00 - 09:30  Kinematic differences between running on water versus running on land in Anolis sagrei Cheu, AY*; Reed, SA; Mann, SD; Bergmann, PJ; Clark University; Clark University; Clark University; Clark University acheu@clarku.edu http://basiliskos.com

An inherent part of animal locomotion is coming into contact with a substrate. These substrates can range from incredibly dense rock with low compliance to packed dirt to flowing sand with high compliance. As a result, animals may have to alter their kinematics to adapt to potential changes in the substrate. The most fluid substrate is water and while water is usually associated with swimming, water running has been observed in a variety of animals ranging from water striders to dolphins. Although the most famous example of running on water comes from the bipedal lizard, Basiliscus vittatus, other lizards have also been observed to run across the surface of the water, namely Hemidactylus platyurus, the house gecko and in this study, Anolis sageri, the brown anole. While the basilisk lizard has adaptations specific to running on water, such as elongated toe fringes on the foot to increase surface area, Anolis, with its terrestrial and arboreal habitat, is not adapted for water running, although it is capable of the behavior. Moreover, Anolis running on water, similar the house gecko, appears to be primarily quadrupedal, where the forelimbs and hindlimbs make contact with the water. In this study, we test if the kinematics used for running are the same between water and land with an animal not adapted for this mode of locomotion. We expect running on water to have lower velocities and acceleration due to increased drag and have higher variation in kinematic variables due to water being a fluid substrate with high compliance. Following our prediction, we found that Anolis runs faster on land and with significant kinematic differences in stride length, duty factor, and the axial variables.