New Zealand's Living Fossil: The Sole Survivor
The tuatara is New Zealand's famous gift to the world, scientifically revered because it is the only survivor of an ancient group of reptiles that roamed the earth at the same time as dinosaurs.
To call them "lizards" is a common mistake; they belong to a distinct order called Rhynchocephalia (beak-heads).
While lizards and snakes evolved into thousands of different species, the dinosaur era relatives of tuatara died out about 60 million years ago, leaving the tuatara as the last standing member of this lineage.
While lizards and snakes evolved into thousands of different species, the dinosaur era relatives of tuatara died out about 60 million years ago, leaving the tuatara as the last standing member of this lineage.
This is why the tuatara is often called a ‘living fossil’ - they provide a biological window into the Triassic period, over 200 million years ago.
Physiological Marvels: The Third Eye
One of the most fascinating "expert" facts about the tuatara is their "third eye." Located on the top of their head, this parietal eye has a retina, lens, cornea, and nerve endings.
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| Hi, I'm Terry Tuatara, I breathe only once per hour! |
Physiological Marvels: The Third Eye
One of the most fascinating "expert" facts about the tuatara is their "third eye." Located on the top of their head, this parietal eye has a retina, lens, cornea, and nerve endings.
While it is visible in hatchlings as a translucent patch, it eventually becomes covered with scales.
It doesn't see images, but it absorbs UV light to regulate their circadian rhythms and seasonal cycles.
A Diet of Opportunity
Tuatara are famous for feeding on the New Zealand weta, a giant flightless cricket that is an ideal meal for this nocturnal hunter.
A Diet of Opportunity
Tuatara are famous for feeding on the New Zealand weta, a giant flightless cricket that is an ideal meal for this nocturnal hunter.
However, they are opportunistic carnivores that predominantly prey on a wide variety of invertebrates, including beetles, crickets, and spiders.
Their unique dentition aids this diet: they have two rows of teeth on the top jaw and one on the bottom. When they bite, the bottom row slides between the top two, creating a shearing mechanism perfect for sawing through the hard exoskeletons of insects.
Their unique dentition aids this diet: they have two rows of teeth on the top jaw and one on the bottom. When they bite, the bottom row slides between the top two, creating a shearing mechanism perfect for sawing through the hard exoskeletons of insects.
Their diet also consists of frogs, lizards, and even their own young (cannibalism is a known threat in dense populations).
Conservation and Habitat
Tuatara once lived throughout the mainland of New Zealand, but the introduction of mammalian predators - specifically rats (kiore) and later Europeans - drove them to extinction in that habitat. They are unable to reproduce fast enough to survive predation; a female breeds only once every 2 to 5 years, and the eggs take up to 15 months to hatch.
They are now found only on 37 off-shore islands and mainland islands, protected by strict biosecurity to keep them predator-free. This includes specific entities like the Karori Sanctuary (Zealandia), which re-established the first wild mainland population in over 200 years.
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| Weta ya reckon? Nice picture? |
Conservation and Habitat
Tuatara once lived throughout the mainland of New Zealand, but the introduction of mammalian predators - specifically rats (kiore) and later Europeans - drove them to extinction in that habitat. They are unable to reproduce fast enough to survive predation; a female breeds only once every 2 to 5 years, and the eggs take up to 15 months to hatch.
They are now found only on 37 off-shore islands and mainland islands, protected by strict biosecurity to keep them predator-free. This includes specific entities like the Karori Sanctuary (Zealandia), which re-established the first wild mainland population in over 200 years.
Taxonomy: One Species or Two?
Historically, science stated there were two species. Sphenodon punctatus is the common tuatara, while the Brothers Island tuatara (formerly Sphenodon guntheri) was considered distinct. However, recent genetic work typically classifies them all as a single species, Sphenodon punctatus, with significant geographic variation.
For management purposes, we still distinguish the Cook Strait tuatara which live on Stephen's Island (Takapourewa) in the Marlborough Sounds—home to the densest population of tuatara on earth (over 30,000 animals).
The Northern tuatara, Sphenodon punctatus punctatus, is a sub-group which live on offshore islands around the north of the North Island. Total tuatara population on all these islands is estimated to be between 50,000 and 100,000.
The Seabird Connection
Tuatara share a complex relationship with burrowing seabirds.
Historically, science stated there were two species. Sphenodon punctatus is the common tuatara, while the Brothers Island tuatara (formerly Sphenodon guntheri) was considered distinct. However, recent genetic work typically classifies them all as a single species, Sphenodon punctatus, with significant geographic variation.
For management purposes, we still distinguish the Cook Strait tuatara which live on Stephen's Island (Takapourewa) in the Marlborough Sounds—home to the densest population of tuatara on earth (over 30,000 animals).
The Northern tuatara, Sphenodon punctatus punctatus, is a sub-group which live on offshore islands around the north of the North Island. Total tuatara population on all these islands is estimated to be between 50,000 and 100,000.
The Seabird Connection
Tuatara share a complex relationship with burrowing seabirds.
They often co-habit in the burrows of petrels and shearwaters. It is a relationship of convenience and terror; the tuatara benefits from the guano which attracts beetles, but they also eat bird's eggs and, fun fact, baby chicks like baby petrel which they find unprotected in nest burrows.
Tuatara are often described as cousins with Komodo Dragons, in the sense they are living relatives of the ancient dinosaurs, though they sit on an entirely different branch of the reptile family tree. Unlike the tropical Komodo, tuatara thrive in cool weather, remaining active in temperatures as low as 5°C (41°F).
Extra for Experts: Tuatara are known to have a low sex drive and incredibly long lifespans (potentially 100+ years). Perhaps the most famous example is Henry, a resident of the Southland Museum. This Tuatara took one hundred years before he popped his cherry, becoming a father for the first time at age 111!
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| You wanna share my baby Petrel? |
Tuatara are often described as cousins with Komodo Dragons, in the sense they are living relatives of the ancient dinosaurs, though they sit on an entirely different branch of the reptile family tree. Unlike the tropical Komodo, tuatara thrive in cool weather, remaining active in temperatures as low as 5°C (41°F).
Extra for Experts: Tuatara are known to have a low sex drive and incredibly long lifespans (potentially 100+ years). Perhaps the most famous example is Henry, a resident of the Southland Museum. This Tuatara took one hundred years before he popped his cherry, becoming a father for the first time at age 111!
