A reptile of the order Rhynchocephalia ("beak-heads") whose closest relatives became extinct over 60 million years ago.
Found on several outlying islands around the coast of New Zealand, the tuatara is a nocturnal animal. During the day, the tuatara lives in burrows, often shared with petrels and shearwaters. Tutatara will eat the chicks of these sea birds, however their more usual diet consists of insects and lizards.
Tuatara have an extremely long life cycle. Sexual maturity takes aroung 20 years from hatching. Eggs are layed in spring and early summer in a shallow hole and then covered with soil. Hatching can occur up to 15 months after the eggs are laid, although eggs have been hatched from a clutch of eggs only nine months after laying. The developing embryos show an unusual characteristic of hibernating over winter. Young hatchlings run the risk of being eaten by adults, however those that survive can grow up to a weight of 1kg in males, although typically most animals never achieve this size, and females are considerably smaller. Growth has been measured up to at least 50 years of age, and there are estimates that tuatara may live up to several hundred years.
As far as Marlborough is concerned, the most significant population of tuatara is on Stephen's Island, in Cook Strait. Access to this island is strictly controlled by the Department of Conservation, and visitor access is normally not permitted. Other populations of tuatara also occur on islands off the North Island, including Little Barrier Island in the Hauraki Gulf. Originally tuatara were widespread throughout New Zealand, occuring on the mainlaind in addition to their current range on a few islands.