Tuatara: New Zealand reptiles

It has survived ice ages, volcanic eruptions and the intrusion of humans on its South Pacific island home, but New Zealand's last survivor of the dinosaur age may become extinct due to global warming.

Mounted with spiny scales from head to tail and covered by rough, grey skin that disguises them among the trees, the tuatara is one of the world's oldest living creatures.

But the lizard-like reptile is facing increasing risk of extinction from global warming because of its dependency on the surrounding temperature, which determines the sexes of unborn young while still in their eggs.

So named by New Zealand's indigenous Maori people because of the spines on its back, the tuatara is the only survivor of its species of reptile that flourished during the age of the dinosaurs, some 200 million years ago.

It can grow up to 20 inches and weigh up to 2.2 pounds and like its reptile relative, the turtle, the slow-moving tuatara can live for more than 100 years, feeding mainly on insects.

But scientists say its long life span as well as its four-year breeding cycle - relatively slow for a reptile - will make the adaptation process more difficult.