Why are tuatara not considered lizards

Absolutely not it is a "Sphenodantia" a living fossel

The tuatara is only found in New Zealand and is in danger of becoming extinct!

It is a reptile but not a lizard.

It is the last remaining member of the ancient group of reptiles, Sphenodontia.

Tuatara is a Maori word meaning "peaks on the back". It is easy to see why.

The tuatara is famous because it is a very ancient - it is the only survivor of a large group of reptiles that roamed the earth at the same time as dinosaurs. It hasn't changed its form much in over 225 million years! The relatives of tuatara died out about 60 million years ago which is why the tuatara is sometimes called a 'living fossil' - cool.

You might have thought tuatara are lizards… but they're not.

  • The arrangement of their teeth is very special. The single row of teeth in the lower jaw fits between two rows of teeth in the upper jaw. This helps tuatara tear apart hard insects such as weta, and chew the heads off small seabirds - yuck!
  • Tuatara mate differently fromlizards. The male tuatara does not have a penis; he mounts the female and passes sperm straight from his cloaca to hers (the cloaca is the hole that sperm enters the female through).
  • They have a gland beneath the skin on the head, which contains a simple 'third eye'.
  • Lizards have visible ear openings but tuatara do not.

But like lizards, if they lose their tails they are able to regrow them - excellent!

What's this about a 'third eye' ??

The 'third eye' is visible under young tuatara's skin and becomes covered with scales after four to six months. The 'third eye' soaks up UV (ultra violet) rays in the first few months of the tuatara's life. The young tuatara get Vitamin D from the UV rays, which helps them grow into healthy adult tuatara.

Tuatara History…

People used to think that the tuatara was a lizard. But in 1867, Dr Albert Gunther, the curator at the British Museum in London examined a bottled tuatara specimen and said 'It's not a lizard!' Gunther linked it to the group of reptiles called Rhynchocephalia, thought to be long extinct land-based reptiles (Rhynchocephalia is now known as Sphenodontia).

In 1989 Dr Charles Daugherty, a professor at Victoria University in Wellington, discovered that there were two species of tuatara, Sphenodon punctatus and Sphenodon guntheri.

Know your tuatara

The most common species is known simply as tuatara (Sphenodon punctatus, Cook Strait tuatara). There are around 50,000 of them living on Stephen's Island in the Marlborough Sounds. Some more live on the Trios Group of Islands also in the Marlborough Sounds.

The only named sub-species of Sphenodon punctatus is Sphenodon punctatus punctatus, Northern tuatara. There is a small population living on Little Barrier Island, the rest are spread over 24 islands in the Hauraki Gulf, off Northland, the Coromandel Peninsula and the Bay of Plenty.

There are only about 400 adults of the second species Sphenodon guntheri, Brother's Island tuatara (known as Gunther's or Brothers tuatara). They are slightly smaller than the other tuatara and live in a patch of scrub on the top of tiny North Brother Island in the Marlborough Sounds. Although they are fairly safe at present, they are always at risk from rats coming onto the island, from fires and from poaching.

The male tuatara grows to an average length of 60cm, weighs around 1kg and has an obvious crest of spines along its back. The female tuatara is smaller; they grow to an average length of 50cm and weigh about 550grams. The female's crest of spines is not as prominent as the male's.

Having babies is a slow process…

Tuatara reach sexual maturity between 15 and 20 years.

  1. Once every two to five years the female will be ready to mate
  2. Males will sit outside their burrows and when a female walks past he will circle her. If the female is interested they will mate.
  3. About 8-9 months after mating the female will lay and bury 6-10 eggs in a sunny nesting site
  4. After 11-16 months the baby tuatara will hatch

Like many other endangered species in New Zealand, a slow breeding cycle has not enabled the tuatara population to keep up with the death rate caused by predators and people. Learn how people are helping the tuatara on the Tuatara Conservation page.

Tuatara are interesting - and a bit weird…

  • They are capable of holding their breath for nearly an hour
  • Tuatara have one of the slowest growth rates of any reptile
  • Tuatara keep growing until they are about 35 years old
  • They will share burrows with birds, but a male might bite off a baby bird's head if it is hungry - which doesn't make it a very good house guest!
  • Male tuatara can weigh up to 1500grams
  • A tuatara's average life span is about 60 years but they can live to be over 100 years old
  • At an average of 50cm long, the tuatara's size today is maybe only half of what it once was
  • Like other reptiles, tuatara are cold-blooded, which means their temperatures change with the air temperature.
  • Tuatara are nocturnal and prefer cool weather. However they will often bask in the sun to warm their bodies - but they are careful not to over-heat.
  • Young tuatara usually hunt for food during the day - to avoid being eaten by adult tuatara at night!
  • The colour of tuatara ranges from olive green to brown to orange-red, and they can change colour over their lifetime
  • They shed their skin once a year
  • On warm nights they come out to hunt for food - mainly insects, lizards and seabird eggs and chicks.
  • Tuatara use their 'egg tooth', a spike on the end of their snout, to break out of their egg. The 'egg tooth' will fall off during the first three weeks of life.
  • The male has a distinctive crest of spines running along the neck and down the back which he can fan out to attract females or when fighting with other males.

The scientific name for cold-blooded is 'poikilothermic'

Scientists at Victoria University of Wellington have been breeding tuatara in captivity and have made an interesting discovery… Tuatara incubated at 21° C had a 50/50 chance of being born male or female, but at 22° C, 80% were likely to be males. At 20° C, 80% were likely to be females. At 18° C all tuatara hatched were female - what a cool discovery!

WOW - the tuatara is an amazing creature!

And New Zealand is the only place in the whole world where it can be found in the wild.

It's great that scientists have learnt so much about the tuatara. It means everyone can help it to survive and not become extinct.

But the tuatara could become extinct if people do not protect it and look after the tuatara populations on our offshore islands and mainland sanctuaries … learn about Tuatara Conservation

This page was updated on 20 March, 2009

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hopefully this helped the people wanting to know if a tuatara is a lizard=)