Hailing from the temperate forests of New Zealand's northern islands, the tuatara is a reptile like absolutely no other. Though it looks like a lizard, it is anything but the last of a mostly extinct group of reptiles known as the rhynchocephalians. Read on to learn more about this fascinating reptile!
1. The tuatara is an animal of its own
At first glance, the tuatara looks like your average lizard. However, it belongs to a separate group of reptiles known as the rhynchocephalians. It is the last surviving species of its kind, with all other rhynchocephalians becoming extinct. Rhynchocephalians diverged from the squamates (lizards and snakes) around 240 million years ago, during the Triassic period.
Most species have been found as fossil remains, with most dating back to the time of the dinosaurs. Some were herbivorous, while others distinctly adapted to an almost fully aquatic lifestyle.
The tuatara’s name is Māori in origin: it translates to “peaks on the back” (referring to the tuatara’s back spines, which are larger in males). Because the tuatara is the last surviving species of an ancient lineage, it is regarded by some to be a “living fossil”. However, this term is often opposed by scientists as many organisms referred to as such are morphologically distinct from their ancient relatives.
Two subspecies of tuataras exist: the northern tuatara and the Brothers Island tuatara. The Brothers Island tuatara is slightly rarer than the northern tuatara and has a few notable physical differences.
Brothers Island tuataras are slightly smaller than their northern cousins and are also yellower/greener in color (while also sporting whitish-yellow patches on their skin). Until recently, it was once thought that both tuataras were separate species.
2. It has many unique anatomical traits
The tuatara may look like an ordinary lizard-like creature at first glance, but it sports a variety of traits that make this wonderful animal unique. For instance, its teeth arrangement is unlike any other living reptile’s. Its front upper teeth protrude almost like a beak, and it also sports two rows of upper teeth in its mouth. Since it only has a single bottom row of teeth, the top rows align almost perfectly when its mouth is closed. Its teeth are fused to the jaw, known as acrodonty.
The tuatara’s teeth help chew its prey, which consists mainly of insects. However, it will also prey upon lizards, shorebird chicks, and eggs. One favored prey item of tuataras is the weta, which are large, flightless crickets that are found only in New Zealand. Since tuataras do not replace their teeth, they often get worn down with age. Older tuataras must resort to preying upon softer prey items, such as worms and slugs.
Tuataras also do not sport any external ears. Like most lizards, though, it sports a photosensory organ known as the “parietal” or “third eye”, which appears clearly in juvenile tuataras. Like a true eye, it has a lens and a retina but serves no function in vision. Instead, it probably assists in thermoregulation or aiding its biological clock. This eye is much more visible in juveniles as it becomes covered in skin when it matures.
3. Tuataras can live a long time
The tuatara’s lifestyle is slow-paced. An average tuatara lives around 60 years old in the wild, but individuals have been reported to live up to 100 years of age. Tuataras take around 13-20 years to sexually mature, and females only reproduce around every two to five years. Even their eggs incubate very slowly: it takes around 12-15 months to hatch! No other reptile has an incubation time this long.
The tuatara’s slow and steady lifestyle is mainly due to its low metabolism, an adaptation to its environment as it hails from colder temperate forests and clearings. Tuataras are mainly nocturnal reptiles, getting the warmth they need by basking during the day. Though nights are colder, the darkness helps them evade predators. Juvenile tuataras, on the other hand, are typically active during the day, as adults will not hesitate to cannibalize their young!
4. Tuataras share burrows with birds
Typically, tuataras are solitary animals, territorial, and prefer to dig their burrows. However, these reptiles will sometimes seek shelter with various shorebirds such as petrels and shearwaters. In many observations, the birds don’t seem to mind the reptiles seeking shelter along with them. Rarely, a tuatara may snack on an egg or an unattended chick, but it doesn’t happen often. Another advantage for the tuatara is that insects are attracted to the bird’s droppings, providing them with another easy snack!
5. Tuataras need our help
As of 2019, the tuatara is currently listed as Least Concern by the IUCN Red List. In the islands on which they survive, these reptiles can be found in high densities. However, they've been fully wiped out on the mainland due to invasive predators such as rats, cats, and dogs. The Brothers Island tuatara is also considered to be a threatened species.
The tuatara was fully granted protection by the New Zealand government in 1895. Decades later, conservation programs have been established to save this species from going extinct. For instance, biologists have been working on fully eradicating rats on as many islands as possible. After the rats are exterminated, tuataras are then reintroduced on those islands as an insurance population. Other native animals, such as birds and insects, also benefit from the removal of invasive rats.
Researchers may also collect tuatara eggs from the wild to allow them to hatch safely in captivity. The babies would then be released with less fear of predation. Tuataras are difficult to breed in captivity, but a few places are learning how to propagate this reptile. In 2016, the Chester Zoo became the first zoological facility outside of New Zealand to successfully breed the tuatara.
Even though the tuatara overall isn’t considered an endangered species, its current survival is fully dependent on conservation management. You can help this magnificent reptile by raising awareness among your friends and family. You can also support conservation organizations that are working to save the tuatara and its habitat.