Spiky scales run down the back of the tuatara and along their tail. This is larger in males than in females. The crest is made up of triangular folds of skin. When displaying it they can flatten it out. They have scaly skin which is coloured green or brown in colour this may change over the course of their life as they shed their skin at least once each year.
Their upper jaw is shaped like a beak. They have one bottom row of teeth and two on the top.
On top of the head tuataras have what is known as a third eye or ‘parietal eye.’ This is able to see when they hatch but by 6 months old opaque scales cover it. Scientists are still yet to work out the purpose of this eye. One theory suggests that it helps to absorb ultraviolet rays which they use to manufacture DNA.
Tuatara reach up to 80cm (31.5in) long and weigh up to 1.3kg (2.9lbs). Females are smaller than males.
As they grow the tuataras teeth begin to wear down. Over time they need to take to feeding upon softer foods which they can chew between their gums as the teeth wear down.
Average 60 years
Wild 100 years
— AD —
Tuataras are native to New Zealand. They were previously confined to just 32 offshore islands. Recently a hatchling was seen on the island showing that release programs may be successful.
They make their home in scrubland.
Males will find a females burrow around March and begin sitting outside hoping she will emerge and they can mate. They puff out the spines around the neck to impress her. Males may breed every year but females generally only reproduce every two to five years.
Once the female is ready to mate the pair will rub their cloacas together as males have no reproductive organ. The eggs do not automatically begin forming as females can store sperm for up to 12 months.
After this 1 to 19 white, leathery eggs with a soft shell is laid in their burrow. After 12 to 15 months of incubation the eggs hatch. This is the longest incubation period of any reptile. It is this long period which allows rats the opportunity to eat many of the eggs which has led to their numbers decreasing.
What gender the hatchlings are depends on what temperature they are incubated at. A change of 1oC (1.8oF) is enough to change males to females. Scientists believe that climate change could lead to the decline of tuataras as there will be more males in the population.
Following hatching these young tuatara are on their own with the mother not staying around to protect them. It takes 10-20 years for them to mature and be able to produce their own young.
Tuataras are nocturnal reptiles. On occasion though they will warm their bodies by sitting in the sun. Young tuatara will be most active during the day and hide under logs and stones at night so they can avoid the cannibalistic adults. Over winter tuataras will hibernate.
On most occasions tuataras dig their own burrow. During the breeding season of burrowing seabirds like petrels, shearwaters and prions they may use the nest of these birds.
They will fiercely defend their territory. They have a bite that they use on predators which can inflict severe damage.
The only predators of the tuatara are those which have been introduced including stouts, dogs, foxes, cats and rats.
A tuatara known as Henry bred at 100 years old in 2009. He needed to have a cancerous tumor removed before he could breed.
Up until 2006 when it was phased out New Zealand’s five-cent coin featured a tuatara on one side.
Tuataras are the only surviving members of the order Rhynchocephalia which mostly existed 200 million years ago.
Their name “tuatara” means “peaks on the back” in the Māori language.
The Brothers Island tuatara was not discovered until 1989. There are only around 600 of these tuatara.
By KeresH (Own work) [CC BY 3.0 (http://creativecommons.org/licenses/by/3.0)], via Wikimedia Commons
By KeresH (Own work) [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0) or GFDL (http://www.gnu.org/copyleft/fdl.html)], via Wikimedia Commons
Australasian Reptile & Amphibian Specialist Group. 1996. Sphenodon punctatus. The IUCN Red List of Threatened Species 1996: e.T20613A9214781. https://dx.doi.org/10.2305/IUCN.UK.1996.RLTS.T20613A9214781.en. Downloaded on 27 April 2020.