Locomotor kinematics of the central bearded dragon Pogona vitticeps: influence of substrate and gradient

Abstract

Animals must be able to move through a variety of challenging and complex environments, including up and down various gradients of incline and decline, as well as locomoting across differing types of substrate. Their ability to locomote efficiently and quickly through their natural environment facilitates finding food, finding a mate, or escaping predators, among other important functions for survival. Therefore, an animal’s locomotor abilities form an intrinsic part of their overall fitness. Investigating how an animal moves through its environment is especially relevant given the potential effects of climate change and urbanisation on the natural environment, as this will impact how and where they move, as well as how much energy they will utilise to locomote across varied surfaces. Being ectotherms, lizards may be particularly vulnerable to changes in climate and increasing urbanisation, and therefore it is important to determine a baseline of how their kinematics and overall performance may change depending upon their environment. This study seeks to investigate how degrees of incline and decline, as well as differing substrates, impact the kinematic behaviours and speed in the central bearded dragon Pogona vitticeps. To do this, the lizards were made to locomote down various trackways, comprising of differing inclines and declines (+15°, +7°, 0°, -7°, -15°), as well as on flat trackways made of sand and gravel. It was found that, although there were no significant differences found in performance between types of substrate, the composition of the substrate had a significant impact on the kinematics of the central bearded dragon, particularly in regards to stride length and stride frequency. The degrees of incline and decline also had a significant impact on kinematics, as well as overall speed, although these results were not consistent based on the level of incline and decline. The results indicate that lizards will modulate their kinematics in order to best move on a particular surface or gradient, but that inter- and intraspecific differences in regards to locomotion must be acknowledged as a factor that will impact their kinematic behaviours.

Date of Award	1 Aug 2021
Original language	English
Awarding Institution	The University of Manchester
Supervisor	William Sellers (Supervisor), Jonathan Codd (Supervisor) & Robert Nudds (Supervisor)