tuatara

The lizardlike tuatara is found on some of the islands and rocky stacks off New Zealand. It is the sole remaining representative of a family of reptiles which first evolved before the dinosaurs. It has a third ‘eye’ on the top of its head which is sensitive to light, although is unable actually to ‘see’.

Lizardlike reptile of the genus Sphenodon. It grows up to 70 cm/2.3 ft long, is greenish black, and has a spiny crest down its back. On the top of its head is the pineal body, or so-called ‘third eye’, linked to the brain, which probably acts as a kind of light meter. It has remained unchanged for 220 million years, and is the sole survivor of the reptilian order Rhynchocephalia. It has an average lifespan of 60 years and reaches sexual maturity for a decade. It lays eggs in burrows that it shares with seabirds, and has the longest incubation period of all reptiles (up to 15 months).

S. punctatus is found on about 30 small islands off New Zealand, whereas S. guntheri has survived on one island only, and numbers around 300 individuals. In an attempt to found a second colony of S. guntheri, 50 4–6 year olds, reared in semi-natural captivity, along with 20 adults from the existing population, were released on to a new island November 1995. At the end of 1999 there were approximately 400 S. guntheri.