No evidence for across-population scent discrimination of cloacal gland secretions in Tuatara (Sphenodon punctatus)

Chemically mediated interactions are an important component of reptile life. Tuatara (Sphenodon punctatus) have been documented to locate prey by olfaction, and the recent discovery of a cloacal gland secretion (tuataric acid) suggests chemicals may be used as social signals. Social discrimination of recognized Tuatara populations (i.e., Cook Strait and northern versus Brothers) via chemosensory means has yet to be determined. To explore whether Tuatara react to cloacal gland odors or respond differently to the odor of a different population, three response variables were measured within 60 cm and 30 cm of a scent source within a captive colony: 1) time of first approach; 2) total number of approaches; and 3) total time. Ten male Cook Strait Tuatara were sequentially presented with three treatments: control (distilled water); male North Brother odor; and male Cook Strait odor. Although no significant differences in response were detected across odors and the control, on average, cloacal gland secretions were investigated faster, more often, and for longer than the water control. Further, four of the 10 test subjects made physical contact with the treatment containers when they contained cloacal gland secretions"”this never occurred under control conditions. Although preliminary, our study provides insight into the potential role of chemical signals in Tuatara.