Courtship, Mating and Male Combat in Tuatara, Sphenodon punctatus

Abstract

The tuatara, Sphenodon punctatus, is the sole extant member of the reptilian order Rhynchocephalia. Although formerly more widely distributed, this species is presently restricted to about 30 islands off of the coast of New Zealand (Robb, 1977; Gans, 1983). Its relict status and structural similarity to Mesozoic rhynchocephalians have prompted numerous studies on its life history (Dawbin, 1962; Sharell, 1966), physiology (Stebbins, 1958; Werner and Whitaker, 1978) and morphology (Ostrom, 1962; Maderson, 1968; Robb, 1977; Gorniak et al., 1982). Sphenodon is unique among the Recent reptiles in its diapsid skull, associated with a mammal-like food-reduction system (Gorniak et al., 1982), and in its lack of a copulatory organ (Robb, 1977). However, literature dealing with behavior of the tuatara remains scanty (Northcutt and Heath, 1973; Ireland and Cans, 1977; Robb, 1977; Dawbin, 1982a; also other papers in Newman, 1982). The only account of its social behavior is a brief, recent report (Dawbin, 1982b); indeed it is uncertain whether it has ever been bred in captivity. The present report documents successful courtship, mating and male combat with dominance in Sphenodon punctatus. Two adult males and one adult female were