Tuatara

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The tuatara is an incredibly unique nocturnal reptile living only in New Zealand. From the outside, they don’t look much different than other lizards, except, maybe, that they are a little stockier. One of their main differences is that they have no external ear openings. They are still able to hear, though. They also have teeth, unlike most lizards. These are not normal teeth, but they are actually serrations of the jaw bone.

Scientists presume that there used to be other lizards like the tuatara, but these are all extinct. In fact, tuataras are so unique that they are given their own Order! They are classified separately from lizards! So, while they are not scientifically lizards, I’ll probably still refer to them as lizards just to make things easier.

Another feature tuataras have is the row of spikes going down their backs. In fact, this is where their name came from. “Tuatara” comes from a Maori word meaning “peaks on the back.” These creatures have an extremely low metabolism. Because of this, they have the lowest body temperature of any reptile and can survive breathing just once an hour!

One bizarre feature tuataras, and some lizard species have is the third eye on top of their head. This eye, called the parietal eye, is actually located beneath the creature’s skin. Its exact purpose is unknown, as it only really senses light. It can’t sense color or form images. Most scientists think it is used to make sure the animal doesn’t get too much or too little sunlight.

Size

Tuataras are larger than most lizards in the United States. Males, which are larger than the females, can be up to two feet (61 cm) long, while the females are one and a half feet, or 18 inches (45 cm). Both of these measures include the tail. Without the tail, they can be up to 11 inches (28 cm) long! Some sources say they may be up to 31 inches (80 cm) with the tail!

The difference in size between males and females is even more pronounced with their weight. Females only weigh about 1.1 pounds (0.5 kg), while males are twice as much, about 2.2 pounds (1 kg). These are average weights, some may be as large as 3 pounds (1.4 kg).

Diet

Like most reptiles, tuataras are carnivores. Smaller lizards might eat just insects, and tuataras do eat several types of insects. Probably their favorite insect is the weta, a large cricket-like insect also living only in New Zealand.

Insects aren’t the only prey tuataras have. They will also eat worms, birds, snails, frogs, birds, eggs, lizards, and sometimes even other tuataras. Because of their low metabolism, these creatures eat much less frequently than other reptiles do.

Habitat and range

As I mentioned earlier, tuataras live only in New Zealand. New Zealand is normally thought of as two islands, but these creatures don’t actually live on either of these islands. Instead, they live on a thirty or so smaller islands off the coast of the larger ones. They are thought to have been common on the main islands, but they went extinct there hundreds of years ago.

The Brother’s island tuatara, which is a subspecies of the tuatara, only lives naturally on tiny Brother Island. Populations of this animal have been started on three other islands.

The islands these lizards live on are mild yet humid. They consist of forests and open areas with brush. The crumbly soil in these areas provides good places for the tuatara to burrow.

Status and threats

Despite having such a small range, these creatures are classified as Least Concern on the IUCN Redlist. Surprisingly, other sources consider them to be much more threatened. They are in the most endangered of the three classifications on CITES, and there are several laws in new Zealand protecting it.

Tuataras are thought to have gone extinct from mainland New Zealand after the introduction of rats, and other predators. They would prey on tuatara eggs, juveniles, and adults. There are rats on the islands where tuataras live now as well, but they are not enough to make these lizards go extinct. Although they have no natural predators, wild cats, dogs, foxes, and other predators, all of which have been introduced, are cause for concern, especially if the predators’ population rises.

Reproduction

It can take up to 20 years before tuataras are ready to reproduce. Once they reach this age, they will mate between the months of January and March. These are the summer months in New Zealand. Males become extremely territorial at this time, and they will sometimes bite other males that intrude on their territory. When an interested female comes, the male will do a bizarre ritual, slowly walking around her stiff-legged.

The females will not lay their eggs until the spring, which in New Zealand is from October to December. She will only lay between 5 and 20 eggs, which is one of the reasons the tuatara population is not as large as it could be. Another reason is that a given female will only mate once every four years! After she lays the eggs and buries them in the ground, she will guard them for a few days, but leave soon afterward.

The eggs hatch later, between 11 and 16 months, giving tuataras one of the longest incubation periods on any reptile! During the winter months, the embryos stop developing, which increases the incubation time

As with most reptiles, the temperature at which the eggs are incubated determines whether they are male or female. Unlike other reptiles, warmer temperatures produce males, and cooler temperatures produce females, instead of the other way around.

Tuataras are extremely long-lived animals. They have an average lifespan of about 75 years, but they can live for up to 100 years!

Don’t forget to scroll down and comment your guess about what the next animal is!

Sources:

Photo credits:

  • Tuatara – KeresH
  • Mystery animal – Public Domain
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