We jump back to New Zealand to cover one of the most unique animals on our planet, the Tuatara. This is a true living fossil. They are the last of their kind, from an ancient order of reptiles, that has survived nearly 240 million years. Because they were isolated on New Zealand for nearly 85 million years, Tuataras survived mass extinctions and have changed little over that time. However, when humans first set foot on New Zealand nearly 700 years ago, the Tuatara was nearly driven to extinction1, albeit unintentionally. Pacific Rats hitched a ride with the early Polynesian settlers and drove many New Zealand species to extinction. Yet, while the Tuatara suffered due to the rats, they have survived and today are a species of focus by New Zealand, and are rebounding. A special podcast for a special species.
Reptiles first emerged around 321 million years ago. While Tuatara are reptiles, they are not lizards. In fact, they are the only remaining species from the Order Rhynchocephalia. This ancient Order of retiles dates back 240 million years, which quickly established themselves all over the world. Dinosaurs did not first emerge on the scene until 230 million years ago. So Tuataras reptiles not emerged before dinosaurs, they lived side by side them. The scientific name for Tuatara is Sphenodon punctatus.
The reason Tuatara was able to survive unlike its close relatives is because it has been isolated on New Zealand for nearly 85 million years ago. What makes New Zealand so unique is, it broke off a supercontinent 85 million years ago, free from any land mammals. Thus, Tuatara were allowed to exist with no land predators that might have led to their eventual extinction. That is, until humans came to New Zealand.
Polynesians first came to New Zealand around 700 years ago. Once settled, they became the Maori peoples. Unintentionally, with the Polynesians came the Pacific Rat (Polynesia Rat). These rodents would hitch along for these oceanic voyages. As a voracious predator (omnivore), these rats established themselves in New Zealand and began to devastate native wildlife, to include the Tuatara. Then when Europeans came along with further pests such as Norway rats, mice, stoats, weasels, and other invasive species, the Tuatara suffered a massive decline in its population.
Today, the Tuatara survives on 32 pest-free islands around New Zealand, as well as in protected reserves on the main North and South Island of New Zealand as a protected species.
This is a reptile that thrives in cooler and cold environments. One of the most fascinating facts about these retiles is they maintain body temperatures of 4 to 55 F (5 to 11 C), which are much lower than other reptiles (average 68 F/20 C). This is a major reason they have been able to survive in New Zealand with its temperate biome. When temperatures drop below 41 F (5 C), Tuatara will go into their dens. This also contributes to their slow metabolism and longevity. In fact, Tuatara can live to be over 100 years old!
They also have a third eye that is covered in scales, so is not for seeing. Rather it is believed to be used to as a photoreceptor to determine the time of day. Their teeth are fused directly to thei jaw, unlike other reptiles. They have primitive hearing. Their diets consist of insects and other invertebrates, small birds, frogs, lizards and even other small tuatara.
While a protected species within New Zealand, Tuatara are classified as Least Concern by the IUCN. Populations are estimated to be over 60,000 but not more than 100,000.