The Tuatara - A Living Fossil

The Tuatara is a lizard like creature that is only found on certain small islands around New Zealand. It is not a true Lizard but a "Living Fossil", a survivor of a group of animals that were once more widespread. They look very much like lizards but their skeleton shows many differences.
They are the only extant members of the Order Sphenodontia, which was well represented by many species during the age of the dinosaurs, some 200 million years ago. All species apart from the tuatara declined and eventually became extinct about 60 million years ago. Only Tuatara survived to become a "living fossil".

Tuataras survived because no predators invaded New Zealand. Terrestrial mammals failed to cross the Tasman Ocean, which separated New Zealand from Australia by opening about 90 million years ago. Tuataras are unusual reptiles, since they like cool weather. They do not survive well over 25 degrees centigrade but can live below 5 degrees, by hibernating in burrows. New Zealand climate was just right.

Then humans arrived and introduced kiore, dogs, ferrets, pigs and cats...

Tuatara once lived throughout the mainland of New Zealand but have survived in the wild only on 32 offshore islands. These islands are characteristically free of rodents and other introduced mammalian predators which are known to prey on eggs and young as well as compete for invertebrate food. The islands are usually occupied by colonies of breeding seabirds that contribute to the fertility and hence the richness of invertebrate and lizard fauna needed by tuatara

We hold three tuatara at the National Wildlife Centre. There are 2 adults and one of their juveniles. The adults were captured on Stephens Island and so we are unsure of their age. They spend their winter months inside wooden burrows in their enclosure and we use a tiny infrared camera inside the male’s burrow to display the tuatara to members of the public. There’s also a heat lamp inside their enclosure.

Rewa, Tahu and Sam are the names of our 3 tuatara. The female, Rewa, was captured on Stephens Island in the 1980s and as she was caught as an adult, we cannot tell how old she is. Her mate, Tahu, was caught in the same place.

In October 2004 we started a “close encounter” talk with the tuatara and members of the public have a chance to see a tuatara up close. There is information given on tuatara behaviour and ecology and the reasons for the decline of this species in the wild.

Did you Know?

Tuatara are not true lizards and are the only living member of their order. Their only relatives are fossils remaining virtually unchanged since dinosaur times 225 million years ago..
Tuatara do everything in life very slowly. They are slow to mature at 15 years of age, slow to reproduce breeding only every 3 or 4 years and they have a long life-span up to 100 years, maybe more.
The female tuatara lays up to 15 eggs in a shallow hole and the young tuataras take 12 months or more to hatch.
If a predator grabs their tail it can fall off and will regrow.
Odd anatomical features including a pineal or third eye on the top of young Tuataras which becomes covered over as adults.
Their teeth are solid projections of the jawbone and the bottom jaw fits perfectly between the two rows of “teeth” on the top jaw.
Unusual breeding characteristics e.g. the determination of gender by the incubation temperature of the eggs. ( Warmer produces males, cooler produces females).
Performs best at temperatures around 12 C – 17 C which is the lowest requirement for warmth in all the reptiles. ( Average temperatures for reptiles are 25 C – 38 C).
Males have no sexual organ.