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Name || Tuatara |
Scientific Name || Sphenodon species, Sphenodontidae family |
Conservation Status || Endangered |
Habitat || Originally throughout New Zealand, now found only on offshore islands |
Unique Features ||
Tuatara are the only living members of an ancient order of reptiles that evolved around 225 million years ago. Their closest relatives all became extinct 65 million years ago. Tuatara have remained the same over 80 million years due to New Zealand's isolation, and this may be the reason they still survive.
Social Behaviour ||
Tuatara are solitary animals although during the winter the young tuatara will huddle together. The males actively defend their territory but are less vigilant during the colder months.
Diet ||
In the wild, tuatara eat mainly large invertebrates, but have been known to eat their own young as well as the eggs and chicks of the fairy prion - a bird whose burrows they often share. In the zoo they are fed once a week during the summer months and once a fortnight during the winter months.
Reproduction ||
Tuatara reach sexual maturity at about 13 years of age. Several months after mating (but is can take up to four-five years), about five-18 fertilised eggs are buried in a nesting burrow where they take about 13 months to hatch. The average time between clutches can be up to four years. Hatchlings dig their way to the surface and like most reptiles, fend for themselves from birth.
Life Cycle ||
It is thought that adults stop growing at about 60 years of age but they can live longer than 100 years.
Relatives ||
There are three types of tuatara - Northern, Cook Strait and Brothers Island. They have no close living relatives.
Interesting Facts :
- Tuatara means 'old spiny back' in Maori.
- The male is much bigger than the female.
- Tuataras have a third eye. It is on top of the brain between it's other eyes. They cannot actually see out of this eye. 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.
- The most populous island with tuatara is Stephens' Island, in Cook Strait. It was cleared for farming a long time ago and surprisingly the tuatara do very well in this environment.
- The sex of Tuataras is decided by soil temperature around the eggs. Warm soil causes males, cool soil leads to females. Other reptiles show this peculiarity too eg crocodiles and turtles.
- Adult tuatara are mainly nocturnal but the young come out during the day until they are about six months old, which reduces the chances of being eaten by an adult tuatara.
Breeding Programme ||
Wellington Zoo's tuatara are part of a nation-wide breeding programme. Captive breeding is essential for the survival of some populations which share their island with rats, which can raid tuatara nests, eat baby tuatara and compete for tuatara for food.
Environmental Conditions ||
DoC have a cooperative recovery programme in action, where captive bred tuatara are released to predator-free islands.
At Wellington Zoo ||
We hold a group of Cook Strait tuatara which are being studied for breeding purposes. On exhibit in the nocturnal house are Cook Strait tuatara called Spike and Spikette.
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