Tuatara are reptiles but not lizards. Their skull, ribs, teeth, the third eye and the way they mate makes them different. Unique to New Zealand, they are part of an order of ancient reptiles which have existed since the time of the dinosaurs.
Gender depends on climate
Tuatara are slow breeders. They mate in summer and lay eggs the following summer, the eggs hatch the next spring or summer depending on temperature and weather conditions. The gender of the hatchlings is partially determined by the soil temperature around the egg during incubation – males are produced from eggs incubated in warmer conditions and females in cooler conditions.
Scientists at Victoria University found that at 22° C, 80% of tuatara incubated would hatch into males, at 20° C, 80% were likely to be females. Rising temperatures is a concern; with warmer weather it is possible that it will result in significantly more male tuatara than females. Once a population has too many more males than females, not enough young can be produced to replace old animals that die and extinction is inevitable.
In Maori, the name “tuatara” refers to the spiny-looking crest along its back and tail – actually not spines but soft folds of skin that in the male can stiffen when the tuatara is alarmed or courting.
Hendrix the tuatara has been at Hamilton Zoo since 1986. You can see him at the Reptile House. Two male and two female tuatara from Stanley Island in the Marlborough Sounds form part of the Zoo’s captive breeding programme. They are off-display so they are not disturbed.
Tuatara eggs are sent to Victoria University, Wellington, to be carefully incubated. Once hatched the little tuatara are returned to the Zoo to gain weight before release on Stanley Island.
Tuatara are nocturnal so at night they come out of their burrows to eat. However, since much of their energy comes from sunlight, they need to bask in the sun for part of the day. They sit motionless for hours, camouflaged against their background.
Enclosures are designed so the animals can retreat and hide away. This stops them from being stressed. To encourage animals to be active and enable visitors viewing opportunities keepers put invertebrates in the leaf litter.
Ever imagined what tuatara feel like? They have dry, cool skin and muscular bodies. The spine is quite soft and made from keratin. The feet are strong with sharp claws. Like to see a tuatara up close? Please enquire at reception about our animal encounters.
Hendrix looks placid but he bites, and once he’s got your finger you just have to wait until he decides to let go!