tuatara

The tuatara (Sphenodon) is a reptile endemic to New Zealand and the only living member of the order Rhynchocephalia. There are two living species: the common tuatara (Sphenodon punctatus) and the Chatham Island tuatara (Sphenodon guntheri). They resemble lizards but represent an ancient lineage that dates back to the era of the dinosaurs.

Adults typically reach about 50 cm in length, with a heavy body and a low crest along the back. Tuatara have acrodont teeth fused to the jaw and no distinct sockets. A distinctive feature is the parietal eye, or third eye, on the top of the head that is visible in juveniles and helps regulate day-night cycles.

Historically widespread, today they are mostly found on predator-free offshore islands or isolated rocky habitats on the mainland. They are primarily nocturnal or crepuscular, basking to regulate body temperature. Their diet is varied and includes insects, small lizards, seabird eggs, and other invertebrates and vertebrates.

Reproduction is slow: females lay eggs and incubation lasts about 12–16 months, with clutches comprising several eggs. Sex determination is temperature-dependent. Maturity is reached only after many years, and lifespans can approach a century in the wild.

Conservation status is Endangered on the IUCN Red List. Declines are linked to habitat loss and predation by introduced mammals such as rats and cats. Conservation efforts focus on predator control, protection of offshore island habitats, and captive breeding and education programs.