Communication via Biotremors in the Veiled Chameleon (Chamaeleo calyptratus): Part II-Social Contexts

This study extends recent research demonstrating that the veiled chameleon (Chamaeleo calyptratus) can produce and detect biotremors. Chameleons were paired in various social contexts: dominance (male-male; female-female C. calyptratus); courtship (male-female C. calyptratus); heterospecific (C. calyptratus + C. gracilis); and inter-size class dominance (adult + juvenile C. calyptratus). Simultaneous video and accelerometer recordings were used to monitor their behavior and record a total of 398 biotremors. Chamaeleo calyptratus produced biotremors primarily in conspecific dominance and courtship contexts, accounting for 84.7% of the total biotremors recorded, with biotremor production varying greatly between individuals. Biotremors were elicited by visual contact with another conspecific or heterospecific, and trials in which chameleons exhibited visual displays and aggressive behaviors were more likely to record biotremors. Three classes of biotremor were identified-hoots, mini-hoots, and rumbles, which differed significantly in fundamental frequency, duration, and relative intensity. Biotremor frequency decreased with increasing signal duration, and frequency modulation was evident, especially in hoots. Overall, the data show that C. calyptratus utilizes substrate-borne vibrational communication during conspecific and possibly heterospecific interactions.