Publication Date

Spring 2018

Advisor(s) - Committee Chair

Dr. Steve Huskey (Director), Dr. Michael Smith, and Dr. Jarrett Johnson

Degree Program

Department of Biology

Degree Type

Master of Science


Vibratory communication has evolved in numerous animal groups, including insects, spiders, fishes, mammals, and was recently discovered in veiled chameleons (Chamaeleo calyptratus). I examined the mechanism by which C. calyptratus produce these biotremors. Muscle activity data were gathered during simulated anti-predator responses via electromyography (EMG) with simultaneous recordings of biotremor production using an accelerometer. I correlated EMG data with the accelerometer data to implicate the muscles responsible for the production of the biotremors. Mixed-effect linear regression models described the mechanism, and a model selection framework determined which model fit the data best. I then used an analysis of variance to partition the variance to each variable to determine which muscles were most important in the biotremor producing mechanism. The Mm. sternohyoideus superficialis et profundus, Mm. mandibulohyoideus, and M. levator scapulae were active during the production of biotremors. Mean latency calculations revealed that the M. levator scapulae and Mm. mandibulohyoideus activated prior to the vibration onset, and the Mm. sternohyoideus superficialis et profundus activated after the vibration onset. The M. sternohyoideus superficialis then ceased activity prior to vibration cessation, and the M. sternohyoideus profundus, Mm. mandibulohyoideus, and M. levator scapulae ceased activity after the vibration had ended. The description of the biotremor producing mechanism further supports that C. calyptratus can produce biotremors, possibly for communication.


Evolution | Integrative Biology | Systems and Integrative Physiology