The strange tuatara: slowly outliving the dinosaur\

Press, 1 December 1988, Page 12

The strange tuatara: slowly outliving the dinosaur\

From a correspondent for the “Economist” in Wellington NEW ZEALANDERS are keen conservationists, which is just as well considering how: many rare species they have to conserve. About’a third of their native land birds have waddled into the rare, threatened or endangered categories; 11 per cent of the world’s endangered bird species are in New Zealand. Even a beefed-up department of conservation, with a budget of SNZ96M in the current year, cannot provide for every worthy project among this embarrassment of disappearing riches. So it is thanks to a group of scientists at the Victoria University of Wellington that detailed research has been done into the eccentric habits and physiology of one of the country’s oddest evolutionary freaks. The tuatara seems to have survived since the age of the dinosaurs, even though male tuatara have no visible genitals. \ It is the sole surviving representative of the Sphenodontia, one of the four orders which make up the reptile class. The Sphenodontia flourished; with the dinosaurs, and all the rest of them died out about 80M years ago. The tuatara’s striking characteristic, says Dr Alison Cree, of the Victoria University, is the extreme slowness of everything it does. Its life is as long and sedentary as an office clerk’s — up to and possibly beyond 60 years. It rarely ventures more than five metres from its burrow except when nesting, perhaps because of the cold climate in which it lives. The tuatara is out and about when its body temperature is lOdeg. — a temperature at which most other reptiles would be in hibernation. Its methods of reproduction, hitherto a well-kept secret among tuataras, are especially slow. Dr Cree believes that the females usually reproduce only every four to five years. It takes two or more years for a female to manoeuvre enough eggs into position; then, after mating, the eggs are held in the oviduct for seven months before being laid, after which they take 12-16 months to hatch. Mating itself is haphazard because the male has no external copulatory organ. Copulation, which takes place at an inevitably leisured pace (one coupling was timed at 58 minutes), is a matter of close contact and hope. The male climbs on top of the female, wraps its tail around her and tries to manoeuvre a sort of sperm-emitting vent over the right place. The tuatara’s slowness makes it vulnerable. It thrives only in a handful of small, rat-free islands. The Victoria University team would like to see it breed in captivity — a feat not yet consistently achieved. Fortunately, the species is in no immediate danger of disappearing. Dr Cree thinks there are 30,000 tuataras on their main lair of Stephens Island, which they share with a species of scm grasshoppers and other curios. Researchers have to take care not to tread on them when they slowly creep from their burrows to enjoy a warm, damp, and usually sexless summer night. Copyright — the "Economist”