The first Tuataras lived side by side with Dinosaurs and witnessed the geological upheavals which shuffled the continents around the globe like pieces of a jigsaw puzzle. They may have even watched from their burrows as Earth shuddered under the impact of the giant meteorite which some scientists think impacted about 65 million years ago leading to Dinosaur extinction. In the age of mammals which followed, Tuatara disappeared everywhere on Earth, except for Aotearoa/New Zealand, the country which mammals never reached.

Arrival of Man

But all good times end, and the arrival of man sometime between 1000 and 2000 years ago, signalled the beginning of the end.First came Kiore, the Polynesian Rat. Tuatara can co-exist with Kiore under favourable conditions, and does today on some Tuatara islands with a greatly reduced population, but when conditions are less favourable looses the battle, and on at least one island has become extinct as a result of Kiore activity. With the arrival of the Pakeha and introduction of European predators, the battle was lost..Tuatara disappeared from the mainland at the end of last century and today survives only in a diminishing number of offshore habitats including several of the islands of the Hauraki Gulf Maritime Park.

"Living fossil"

Tuatara is known scientifically as a 'living fossil', a distinction shared with a few other species including the coelacanth fish, the horseshoe crab, and the native frogs of New Zealand, which have apparently changed little from extraordinarily ancient origins. There are at least two Tuatara species, one of which has only 400 members, and extinction is a real possibility.The order to which Tuatara belong, Spenodontida, has no other living representatives. The only other Sphenodontidans are fossils.

Tuatara meets Weta

The Tuatara is largely nocturnal but spends part of each day basking at the entrance of the burrow which it comandeers from, and sometimes shares with, Shearwaters and Petrels, which are also sometimes its food, although its predominant diet is insects, such as this Weta, and small lizards.

Tuatara, (old spiny back in Maori) differs from lizards, which it superficially resembles, by extra holes in the skull, boney processes on the ribs, the lack of a copulatory organ in males, and the presence of a third eye, known as the parietal or pineal eye, which contains a rudimentary lens and retina and is connected to the brain by a nerve. However, the whole organ is covered with opaque scales and the formation of an image would be impossible. Some scientists believe that this third eye may function as a light sensor, influencing the amount of time a tuatara spends basking. It is particularly noticeable in hatchlings which have a patch of white scales at top centre of the skull.

Tuatara teeth, also, are different from those of other reptiles. They have a single row of teeth in the lower jaw, and a double row in the upper jaw, the bottom row fitting neatly between the two upper rows.Little more than serrations of the jaw, they are not replaced when worn out or damaged, and some old Tuatara are virtually toothless, chewing their food between smooth jaw bones.


Sex amongst Tuataras

As well as having no male copulatory organ, Tuatara also differs from other animals, in its enormously slow reproduction rate, the process of egg formation taking a female four years, sometimes more, which is longer than in any other reptile. Then the eggs take 12 months to hatch. The development in the early nineties of a viable "hatching in captivity" programme at Victoria University may mark a turning point in the long history of the Tuatara and allow recolonisation of some places from which they have vanished.


Tuatara pops out of its egg

An obvious candidate for a recolonisation programme is the open sanctuary island of Tiritiri Matangi, from which all rats have now been eliminated. Ratfree islands differ dramatically from the rest of New Zealand. Mainland forests are silent today because the birds with which they once teemed have been killed by rats, cats, and stoats, the trees themselves dying because of possums brought from Australia.

To visit a rat-free island is to travel backwards in time for a thousand years, or a million, or ten million, to a time when most of Aotearoa/New Zealand shared the extraordinary biological diversity now found only on islands where introduced mammals are absent. Seabirds fertilise the soil with their droppings, producing the rich plant life that in turn provides for insects, lizards, forest birds, and, where they are present, at the top of the food chain, Tuatara.

On some rat-free islands the average Tuatara weighs 400-500 grams and as many as 2000 share a hectare of forest, almost a tonne of Tuatara to the hectare. Even in poor habitats, there may be 500 tuatara to the hectare.Sadly, this is not the case in the Hauraki Gulf, where those Tuatara which survive share their islands with Kiore and sometimes European rats. The use of Titirtiri Matangi could turn this around.

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