The Tuatara of New Zealand

living fossils. Now just two species of tuatara survive, and only in New Zealand. One is the Brothers Island tuatara which, until recent re-introductions to sanctuaries (safe places for wildlife), only survived on North Brother Island. The other species is the common tuatara, which survives on many other offshore islands. Although the tuatara species appear similar, they have genetic differences. Tuatara bones have been found in many parts of New Zealand. Where dated, they are usually a few hundred to 5,000 years old. It is not known whether these bones are from the two living species or other species that are now extinct. Many anatomical features distinguish tuatara from other living reptiles - for example, they have a defining pattern of openings in the skull and a unique type of haemoglobin in the blood, and males have no external reproductive organ. Adults are between 30 and 75 centimetres long, and weigh between 250 and 1.200 grams. Males are larger than females, and have more developed spines in the crest along the neck, back and tail. The male tuatara courts the female by approaching her with a proud walk. Tuatara mate in late summer, and the female usually lays 6-10 eggs the following spring, in a shallow nest at…