Chemical discrimination of prey by naive neonate Gould's monitorsVaranus gouldii.

Previous studies have demonstrated that actively foraging autarchoglossan lizards rely in part on chemoreception to detect and locate prey. In one of two experiments, neonate Gould's monitorsVaranus gouldii were studied to determine whether they were able to discriminate between multiple prey odors and control odors by tongue-flicking. Responses of lizards to deionized water, a pungency control (cologne), mouse, gecko, and cricket odors on cotton-tipped applicators were studied in experiments using repeated-measures designs and using the tongue-flick attack score (TFAS) as the primary measure of response strength. The TFAS was greater in response to cricket odors than to other prey odors or to either of the control stimuli, and there was no statistically significant difference in response between control stimuli. Range of tongue-flicks elicited by cricket odor were greater than those for other prey odors and control stimuli. Only applicators bearing cricket odor were bitten. In the second experiment, lizards were tested to determine whether they respond differently to chemical stimuli taken from the exoskeleton vs. internal fluids of crickets. TFAS were slightly higher for chemical stimuli taken from internal fluids, but not significantly so. Lizards bit applicators in both conditions. Details of responses to experimental trials are discussed in relation to the feeding behavior of this species.