Social Behavior of the Tuatara, Sphenodon punctatus

The social behavior of tuatara, Sphenodon punctatus, was studied in a natural population on Stephens Island, New Zealand, from January to March, 1987-1989. Study sites were located in both wooded (bush) and open (paddock) habitats. Nocturnal observations were enhanced by using night-vision equipment and elevated viewing platforms. Individuals were identified by idiosyncratic differences in crest morphology. At the peak of courtship activity (late January to the end of February), the behaviors of territorial males were observed and their responses to visual stimuli were tested in the field. Visual stimuli were found to be of significance. A radio-controlled, life-sized tuatara model revealed the importance of nuchal and dorsal crests and female head- nodding in the initiation of male courtship and mating behaviors and territorial defense.