Animal of the Month
January 2016

Name: Tuatara
Scientific Name: Sphenodon
Classification: Reptile

Class: Reptilia
Order: Rhychocephalia
Family: Sphenodontidae
Genus: Sphenodon

Number of Species: 2 (Sphenodon punctatus, Sphenodon guntheri).
Size: 20-23 ½ inches long
Weight: Approx. 0.6-2.2 lbs

Characteristics: Long body and tail, sprawled-out legs, spines on back.
Color(s): Tan, brown or olive-green, white stripes on the underbelly
Behavior: Diurnal when young, nocturnal when fully grown.
Preferred Habitat: Burrows
Range: Several small islands off the coast of New Zealand
Diet: Large insects, beetles, sometimes smaller reptiles, eggs or even juvenile tuataras!
Lifespan: Around or even past 100 years in the wild or captivity.

Status: Sphenodon punctatus is classed as Least Concern,

Status: Sphenodon guntheri is classed as Vulnerable.


It may look like an iguana, but the tuatara is actually its own special kind of reptile. The two species of tuatara are the last surviving members of the order Rynchocephalia, a group of reptiles that was very diverse during the Mesozoic Era when the dinosaurs ruled the Earth. They are usually only found on 32 small islands off the coast of New Zealand, though at one time they were found all over New Zealand. The first species, Sphenodon punctatus, is found on various islands off the coast of New Zealand, while the rarer species Sphenodon guntheri, is only found on Brothers Island.

Tuataras are a good example of how animals are not always what they appear to be. They look like lizards at first glance, as they possess sprawled-out legs, scaly skin, claws, teeth and iguana-like head and a tail. However, upon closer inspection one can see that they are not true lizards. Tuataras have two openings in their skull, while most lizards only have one opening. Tuatara teeth are sharpened edges built into their jaw, rather than individual growing bones. Tuataras also lack eardrums and middle ears, and do not possess external sexual organs. This goes to show that you can’t judge someone before you get to know them!

One bizarre characteristic that they do share with certain reptiles and amphibians is a small “third eye” on top of their head. This is called a parietal eye. Animals with this trait cannot see clear images through their third eye, but they can use it to detect light. This allows them to avoid predators that might sneak up on them, or to navigate during the day. Despite all of this, it is unknown if the tuatara’s parietal eye is functional today, or if it is useless like a human floating rib. Some have theorized that the tuatara’s parietal eye is used to absorb ultraviolet radiation, or to help keep its biological clock in order.

Tuataras are diurnal when they are young, but they become nocturnal during adulthood, hunting for their preferred prey of insects at night. They also will go after smaller lizards, and even juvenile tuataras! They will sometimes come out during the day to bask in the sun. Tuataras will either dig their own burrows to live in, or they will live in old burrows that were made by seabirds. They commonly live near seabirds because the guano left by the seabirds attracts a lot of their prey. They will not stray far from their burrow if they don’t have to.

Tuataras reproduce very slowly. They are not able to reproduce until they are ten years old, and though males will mate every year, females will only mate every two-to-five years as it takes one-to-three years for a female tuatara to generate yolk for eggs, seven months to form the egg shells, and then twelve-to-fifteen months for the eggs to hatch! It takes 30-35 years for a tuatara to grow to its full size. Even when very old, tuataras are still capable of reproducing. Henry, a tuatara who lived at the Southland Museum and Art Gallery in New Zealand, once successfully mated with a female named Mildred. Mildred was in her seventies, and Henry was 111!

The IUCN currently lists Sphenodon punctatus as Least Concern. The more recently discovered Sphenodon guntheri, however, has been classed as vulnerable. In any case, tuataras have been protected since the 1890s. Once found across New Zealand, they are restricted to small islands off the coast. Tuataras are threatened by habitat destruction. They are also victims of the introduced Polynesian rat as these rodents eat their eggs. Their slow reproduction does not help them in these difficult times, and there is concern that their concentrated numbers will limit genetic diversity. Fortunately, there are programs in New Zealand that are working to preserve this living fossil. Sanctuaries have been founded to help preserve their habitat, and New Zealand’s Department of Conservation has partnerships with zoos and museums across the country in an effort to breed tuataras in captivity. The Southland Museum houses about 80 tuataras.

It is important to note that in 2008, a tuatara nest was discovered outside of Wellington, New Zealand. This is the first tuatara nest to have been found on the mainland in two-hundred years! This gives further hope for the future of the species.

To learn more about tuataras and what is being done to protect them, check out these awesome initiatives:

New Zealand Department of Conservation, Tuatara Page—Information about the tuatara and what the Department of Conservation has done and continues to do (and how you can help too!)

Tiritiri Matangi Project, Tuatara Page —This Open Sanctuary protects all of the wildlife on the island of Tiritiri Matangi, including tuataras, and has seen tuataras introduced into the wild.

The Tuatara Genome Project—Dedicated to charting the genome of the tuatara to protect the genetic diversity of the species.


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