Tuatara

The tuatara is a reptile found only on a number of small islands off the coast of New Zealand, the sole living representative of an ancient order of reptiles, Rhynchocephalia, that was far more diverse during the age of dinosaurs, making it one of the most frequently cited living fossils in the animal kingdom. Though it resembles a large lizard, with a spiny crest along its back and greenish-brown skin, it is only distantly related to true lizards, and it retains several primitive anatomical features, including a so-called third eye on the top of the skull that is sensitive to light though not used for vision as adults. Tuatara grow and mature extremely slowly, are active at notably cooler body temperatures than most reptiles, and can live well over a century, among the longest lifespans of any reptile. They feed mainly at night on insects, small reptiles and the eggs and chicks of seabirds, often sharing burrows with nesting petrels. Once found across mainland New Zealand, the species was wiped out there by introduced predators such as rats, and it now survives only on predator-free islands and in carefully managed sanctuaries.