The Sphenodon is the only species in reptilian class of Rhynchocephalia which has been dubbed a ‘living fossil’ as the only surviving member of an ancient group of reptiles that flourished during the time of the dinosaurs. It is found in New Zealand and nearby coast regions and it is commonly known as tuatara in their habitat.

The tuatara is a medium-sized reptile which shows similarities a lizard in appearance. It has a large head, a stout body, powerful limbs with sharp claws, and a thick tail, but it slightly differs from lizards in its internal anatomy. Unlike lizards, the tuatara also has unusual dentition. The tuatara has no external ear opening, although it is still able to hear. The tuatara has olive-green to grey and blackish-brown or pinkish of their body color and is often marked with pale speckles. The newly hatched offspring’s of tuatara are brownish-pink or grey, sometimes with light patches on the body and tail.
A further special feature of the tuatara is that it possesses a ‘third eye’, also known as a parietal or pineal eye, which is located centrally on top of the head, beneath the skin. This ‘eye’ has a lens and retina, but its exact function is unclear. It is sensitive to light but is not thought to form images, instead potentially being involved in regulating the tuatara’s exposure to the sun. The tuatara is nocturnal, burrower, either digging one itself or sharing the burrow of a nesting with some seabird. This reptile has relatively few natural predators, although it may potentially be taken by birds of prey, kingfishers and gulls. If attacked, the tuatara is able to shed its tail and then grow a new one.
It’s generally feed on a variety of small animals, invertebrates such as beetles, crickets and other large insects. Its diet also includes spiders, snails, worms and small lizards, and will even take the eggs and chicks of seabirds, as well as occasional adult birds and some carrion. The reproduction occurs in tuatara during in the summer, between January to March. At this time, males become territorial and will attempt to warn off intruders by inflating their bodies and raising their crests. When courting a female, the male tuatara erects its crest and circles the female in a slow, exaggerated, stiff-legged walk.


Author: Dr. Umesh Garu