Tuatara – Our Living Fossil
The tuatara is an ancient creature that looks like a lizard but their skeleton shows many differences.
They are a ‘living fossil’ – the only survivor of an extinct group of reptiles that lived during the age of the dinosaurs.
Tuatara survived because no predators invaded New Zealand when it separated from Australia about 90 million years ago. They lived throughout the mainland of New Zealand until humans arrived and introduced harmful predators.
Tuatara translated means ‘peaks on the back’.
These spiny crests are made of triangular soft folds of skin, which stiffen during mating or displays of aggression. Tuatara shed their skin at least once per year as adults, and three or four times a year as juveniles. They range in colour from olive green to orange-red, and can change colour over their lifetime.
Tuatara ‘teeth’ are solid projections of the jawbone. The bottom jaw fits perfectly between the two rows of ‘teeth’ on the top jaw, which helps the tuatara to tear its food apart.
Tuatara feed on a wide range of small animals, mainly large insects. Their diet shows seasonal changes and habitat differences. Both male and female tuatara are very territorial. They bite and don’t let go easily!
Young tuatara have a pineal or ‘third eye’ on top of their heads. This ‘eye’ soaks up ultra-violet rays in the first few months of the tuatara’s life, helping it grow. After four to six months, the ‘eye’ becomes covered over with scales. The purpose of this ‘eye’ is still largely a mystery, although theories suggest it may help absorb vitamin D from sunlight or function as a biological clock. It is connected to the pineal gland which produces the hormone melatonin which controls the cycles of waking, sleeping, mating and hibernation.
Tuatara can hear, although they don’t have external ears. Males have no sexual organ; instead, sperm is passed straight from a special hole called the cloaca to the female’s cloaca. If a predator grabs a tuatara’s tail, it can fall off and then grow back.
Of myth and legend
Tuataras were once feared by Maori as the messengers of Whiro, god of death and disaster.
Today, tuataras are regarded as a taonga (treasure), and as the kaitiaki (guardian) of the trails to the realms of the mind and spirit that give humans life.