My research examines the morphological, mechanical and physiological basis of animal movement with an emphasis on how these mechanisms change through evolution and across diverse natural environments.

Trioceros hoehnelii

© 2010 Christopher V. Anderson

Thermal Effects on High-Powered Ballistic Movements

Chameleons, toads and some salamanders feed by way of ballistically projecting their tongue from their mouth to capture prey. These highly specialized feeding mechanisms utilize elastic storage mechanisms, similar in ways to a bow-and-arrow, to launch the tongue. This recoil of elastic elements allows for extreme performance outputs far exceeding that of known muscle properties. My dissertation research under Dr. Stephen Deban focuses on the thermal effects of feeding in chameleons (family Chamaeleonidae) in order to understand how explosively dynamic movements powered by elastic recoil are effected by temperature. We discovered that in addition to producing extreme performance, this elastic recoil also liberates tongue projection from much of the normal decrease in performance associated with muscle-powered movements at low temperatures, allowing them to feed at high performance, even at low temperatures where other sympatric lizard species remain inactive.

The first portion of this study was recently published in the Proceedings of the National Academy of Sciences and was the subject of a range of press coverage. Further research on this topic in the Deban Lab has since examined this interaction in other taxa and additional studies examining the mechanistic basis for this interaction in chameleons are being prepared for publication. Recently I’ve been working with Dr. Deban, Nicholas Larghi and undergraduate researchers in the Deban lab looking at this interaction in a plethodontid salamander.

As organisms grow, their increasing body size results in changes to the way they interact with their environment. An organism’s size and proportions have profound effects on how they are able to move and preform in their surroundings. Similarly, closely related species of different sizes are subject to different constraints on their movements due to their differing body sizes. Dr. Stephen Deban and I have been working with Thomas Sheridan, an undergraduate in the Deban Lab, to look at the scaling patterns of the feeding apparatus of chameleons. By looking at how the size and proportions of the different muscles and bones in the chameleon’s feeding apparatus change with body size, both within a species and between species, we are gaining insights into the functional constraints imposed by body size on spring-loaded ballistic movements, as opposed to more typical musculoskeletal systems.

More to Come!

General Research Interests:

I am interested in research questions aimed at understanding the morphological, biomechanical and physiological mechanisms underlying animal movement. In particular, I am interested in how these mechanisms change through evolution and across diverse natural environments. In my research I attempt to bridge the gap between form and function, between physiological processes, behavior and the environment, and in that way, provide valuable insight to how organisms exist in their natural surroundings. One way I examine these types of questions is through biomechanical examination of reptile and amphibian feeding and locomotion across a range of environmental perturbations. My fascination with the family Chamaeleonidae, however, has resulted in much of my research utilizing these animals as models for the principles I study.   

The following are examples of some of the research I am or have been involved in: