tuatara the last survivor of an ancient reptile order

Size
Length: 40–60 cm, Weight: 0.5–1.2 kg
Lifespan
60–100 years
Diet
Insectivorous - feeds on insects, spiders, wētā, and small lizards. Active at night when temperatures are cool. One of New Zealand's most iconic reptiles, found only on predator-free offshore islands and in mainland sanctuaries.
Habitat
Coastal forests, shrublands, and rocky areas on predator-free offshore islands. Burrows in seabird colonies, sharing tunnels with petrels and shearwaters. Active at night when temperatures are cool, hibernating during winter.
Range
New Zealand - found on predator-free offshore islands and in mainland sanctuaries including Stephens Island, the Mercury Islands, and Zealandia (Wellington). Once widespread throughout both main islands.
Endemism
Endemic
Main Threats
Predation by introduced rats is the primary threat, which wiped out mainland populations. Also threatened by habitat loss and climate change affecting sex ratios (temperature-dependent sex determination). Classified as At Risk - Recovering due to successful translocations to predator-free sanctuaries.
Population
New Zealand's iconic reptile, the last surviving member of an ancient order that flourished 200 million years ago. Classified as At Risk - Recovering, with populations stable on predator-free offshore islands and increasing in mainland sanctuaries following successful translocations.
Conservation Status
Nationally Vulnerable
To look at a Tuatara is to look directly into the Mesozoic era. While they may superficially resemble lizards, they are biologically distinct, belonging to a lineage that diverged from snakes and lizards before the first dinosaur even thought about getting large. They are the ultimate "living fossils", having survived the asteroid that wiped out the T-Rex, only to nearly meet their end at the hands of the Polynesian rat (kiore) and European settlers. They are built for a world that no longer exists - a slow, cool, and patient version of Earth. They possess a unique skeletal structure, including two rows of teeth in the upper jaw that overlap a single row in the lower jaw, creating a "sawing" action that can easily shear through the chitinous armour of a giant weta or the skull of a small seabird. The Tuatara is the master of the "long game". Their metabolism is so incredibly slow that they breathe only about once an hour when resting and can live for well over a century. They do not even reach sexual maturity until they are roughly twenty years old, and females only lay eggs once every two to five years. This glacial pace of life is perfectly suited to the New Zealand climate; unlike most reptiles that require blistering heat to function, Tuatara are most active in temperatures as low as 12°C. They are famously "odd roommates", often sharing their burrows with nesting petrels or shearwaters. In this bizarre arrangement, the seabird provides the burrow and the guano (which attracts the insects the Tuatara eats), and the Tuatara provides "security" - though they are not above occasionally eating the bird's eggs or chicks as a convenience fee. One of their most legendary features is the "third eye" or parietal eye. Visible only in hatchlings before being covered by scales, this eye comes complete with a lens, retina, and nerve endings. While it does not "see" images in the traditional sense, it is a sophisticated solar sensor that helps the Tuatara regulate its circadian rhythms and thermoregulation. It is a biological compass that has guided them through 200 million years of planetary shifts. However, their ancient biology has a modern weakness: temperature-dependent sex determination. If the nest temperature rises even a few degrees due to climate change, all the hatchlings become male, potentially dooming a population to a slow, lonely extinction. Conservation today for the Tuatara is a feat of island-hopping and predator eradication. Thanks to the work of the Department of Conservation and iwi partners, they have been successfully reintroduced to the mainland in fenced sanctuaries, allowing New Zealanders to once again walk the same ground as a prehistoric titan. They are not just animals; they are a biological miracle. To see a Tuatara sitting motionless in the moonlight is to realise that some things do not need to change to be perfect. They have seen the mountains rise, the forests change, and the dinosaurs fall. They are the patient kings of New Zealand, and they are in no hurry to leave.