Tuatara

The tuatara (/tuːəˈtɑːrə/, Māori: [ˈtʉ.a.ta.ɾa]; Sphenodon punctatus) is a species of reptile endemic to New Zealand. Though it looks like a lizard, it is the only living member of a unique group called the order Rhynchocephalia. This special animal has a spiky crest along its back and teeth on the roof of its mouth.

Tuatara first appeared millions of years ago during the Mesozoic era and were once found all over the world. Today, they survive only in a few places, mainly on small islands off the coast of New Zealand. They are important for scientists who study how animals change over time.

Tuatara are protected by law because they face threats from losing their homes and from animals like the Polynesian rat (Rattus exulans). In 2005, tuatara were reintroduced to the mainland at the Karori Wildlife Sanctuary (now named "Zealandia"), marking an important step in helping this unique species recover.

Taxonomy and evolution

The tuatara belongs to a special group of reptiles called Rhynchocephalia. It looks like a lizard but is the only living member of this group. Scientists first thought tuatara were lizards. Later, they found tuatara have features like birds, turtles, and crocodiles. Because of this, they gave tuatara their own group name.

Tuatara have lived on Earth for millions of years. Their ancient relatives were small reptiles from the time of dinosaurs. Today, tuatara are found only in New Zealand. There is one species of tuatara, but there are two types based on where they live. One type has olive brown skin with yellowish patches. The other can be olive green, grey, pink, or brick red with white spots.

Description

Tuatara are the largest reptiles in New Zealand. Adult males can be up to 80 cm long, while females are smaller. They have a spiny crest on their back, which is larger in males. Tuatara change color over their lifetime and shed their skin yearly.

Unlike most lizards, tuatara have a special bar closing the lower part of the skull behind the eye. They also have unique teeth that are fused to their jawbone and do not grow replaced. Tuatara can see well in both day and night and have a special third eye on top of their head that helps them sense light changes.

Tuatara break off their tails when threatened and can regrow them, though it takes a long time. They are active at lower temperatures than most reptiles and can stay active in chilly weather.

Ecology

Tuatara live on islands with birds like petrels, prions, and shearwaters. These birds make holes in the ground to live in, and tuatara use these holes for shelter. The birds leave behind guano, which helps insects live, and tuatara eat these insects. Tuatara eat beetles, crickets, spiders, wētās, earthworms, and snails. They also sometimes eat frogs, lizards, and bird eggs or baby birds.

Both male and female tuatara protect their space. If something gets too close, they might bite it. They hold on tight when they bite. Female tuatara sometimes stay near their nests to keep them safe. Tuatara can get sick from a special kind of tick called the tuatara tick.

Reproduction

Tuatara reproduce very slowly. It takes them 10 to 20 years to be ready to have babies.

When a male wants a female to have babies with him, he makes his skin darker and walks toward her. The female can let him stay or go into her burrow.

Adult males do not have a penis. They put their vent over the female's in a process called a "cloacal kiss" to give her sperm.

Tuatara eggs have soft shells. They take between 12 and 15 months to hatch. The sex of a baby tuatara depends on the temperature of the egg. Warmer temperatures make more males, and cooler temperatures make more females. Tuatara can live for over 100 years.

Genomic characteristics

The tuatara has a very large genome, which is the second largest known among reptiles. Researchers have found many types of genetic elements in its DNA, including over 8,000 non-coding RNA-related elements and around 7,500 LTRs. The tuatara also has 56 genes that help it resist disease and recognize relatives.

The mitochondrial genome of the tuatara is about 18,000 base pairs long and contains genes for proteins, ribosomal RNA, and transfer RNA. These findings show that the tuatara’s genome has special features compared to other animals.

Main article: major histocompatibility complex
Main articles: lepidosaur , Sauropsida

Conservation

Tuatara are protected by New Zealand's Wildlife Act 1953 and are listed under the Convention on International Trade in Endangered Species. This stops people from trading them freely.

Tuatara used to live all over New Zealand, but they disappeared from the main islands long ago. Today, they live on islands without mammals, where they are safe. Scientists are working hard to help tuatara live on the mainland again.

Scientists are also worried about climate change. The temperature when tuatara eggs hatch decides if the baby will be male or female. Warmer temperatures might change this balance.

In many places, people have removed animals that eat tuatara eggs. This has helped tuatara populations grow. Some tuatara have been moved to new islands or zoos to help them survive.

Cultural significance

Tuatara are important in Māori legends and traditions. They are seen as messengers of Whiro, the god of death and disaster, and are considered sacred. Because of this, Māori women were not allowed to eat them. Tuatara are also viewed as guardians of knowledge and special treasures.

In the past, the tuatara appeared on one side of the New Zealand five-cent coin before it was phased out in 2006. The name "Tuatara" was also used for a journal published by Victoria University of Wellington from 1947 until 1993.