What is a Tuatara?
The tuatara's ancestors roamed the earth with the dinosaurs 225 million years ago.
The tuatara is the only survivor of a group of reptiles that roamed the earth at the same time as dinosaurs - about 225 million years ago.
There are two species of tuatara, both of which are endemic to New Zealand. The scientific name for the two species are Cook Strait Tuatara (scientific name: Sphenodon punctatus) and Brothers Island Tuatara (scientific name: Sphenodon guntheri).
Appearance
The tuatara is a greenish, brown reptile that grows to between 50 cm and 80 cm long.
It has distinctive soft spines along the top of its head and down its backbone. Although it looks much like a lizard, tuatara is actually the only surviving member of the order Sphenodontia.
Tuatara don’t have external ears but they are able to hear.
The tuatara is famous for its “third eye” or pineal or parietal eye located in the middle of its forehead. The eye has a small lens and retina, but it becomes covered by a thin layer of opaque scales about 4 to 6 months after birth.
The purpose of this parietal eye is unknown, but some scientists have suggested that it is used as a light sensor as opposed to forming visual objects.
Habitat and Distribution
The tuatara is endemic to New Zealand.
Up until a thousand years ago, tuatara occurred in both the North and South Islands of New Zealand. Now, the tuatara can now only be found on islands in the North Island.
Tuatara tend to live in burrows in native forest, but can often be found occupying abandoned sheep pasture. They will often share burrows with seabirds such as petrels and shearwaters.
Growth
Tuatara has the slowest growth rate of any reptile. It can take as many as 30 to 35 years for a tuatara to reach full size.
Tuatara usually lives to around 60 or 70, but they have been known to live to more than 100. In fact, one tuatara was seen mating last year at the ripe old age of 111.
Diet
Tuatara’s main diet consists of Insects, spiders, earthworms, snails and small lizards. Tuatara have also been known to kill and eat small seabirds and their eggs as well as young tuatara.
Behavior
Tuatara are mainly nocturnal and remain in their burrows during the day and prowl at night. They tend to have a lower body temperature than their environment, and they are active at lower body temperatures than most reptiles. They often come out during the day to bask in the sun.
Although they don’t actually go into hibernation, tuatara will often go six months without food during winter.
Ancestory
The tuatara’s ancestory dates back to the dinosaur time. Ancestors of the tuatara and many other sphenodons were roaming the world 225 million years ago. This was about the time the first dinosaurs appeared.
All other sphenodons disappeared around 65 million years ago and exist only as fossils. As a result, scientists often refer to the tuatara as a “living fossil”.
Tuatara Mating & Breeding
Tuatara reach sexual maturity at between 10 to 20 years of age.
The female, on average, lays between 5 and 18 eggs only once every 4 years, which gives it the longest reproductive cycle of any reptile.
Mating season for tuatara is between January and March. Female tuatara then lay their eggs between October and December.
Hatchlings appear between 12 to 15 months after the eggs were laid. To break the egg, they use their egg tooth (a sharp pointed spike at the end of the snout).
Conservation Status
For millions of years, tuatara populations thrived in New Zealand. Then over the last thousand years or so, tuatara populations declined rapidly, almost to the point of extinction.
The main culprits were introduced rats, cats, dogs, and humans. Not to mention fires and land clearing.
The tuatara, was almost wiped out by the 1700s. In fact, in 1895, the tuatara was one of the first animals in the world to become fully protected by law.
Since then, significant tuatara populations have survived on 32 remote islands around New Zealand. Stephens Island/Takapourewa is home to about 50,000 tuatara, which represents about 90% of the tuatara population.
Since 1996, the IUCN Red List of Threatened Species has listed the Brothers Island Tuatara as Vulnerable and the Cook Strait Tuatara as Lower Risk/least concern, although IUCN has also stated that this needs updating.
Tags: Conservation, new zealand, threatened species, wildlife
