Updated: Feb 29, 2020
The pictures in this blog look like just another lizard. Honestly, though, nothing could be further from the truth. These are pictures of tuataras, the only remaining species from the order Sphenondontia that flourished and thrived over 200 million years ago. However, by 60 million years, all of them had become extinct and the tuatara (Sphenodon punctatus) was the only one remaining. The order of Sphenodontia only contains the tuatara. It is now what could be described as a “living fossil” - who literally walked alongside the terrifying tyrannosaurus rex and the brachiosaurs. Throughout the years, there has been thought to be different species of tuataras but in 2009, it was ruled that these were all just different regional variations of the same animal (Like skin tones in humans vary by where our ancestors originated. People from warm-climates usually have darker skin because melanin, where the pigment resides, is a natural sunscreen and blocking UV rays. However, as people moved further away from the Equator, the need for melanin decreased. There was less sun and our bodies adapted to that.)
Talismans and Tara
The name “tuatara” comes from the Māori. “Tua” means “spiny” and “Tara” means a plantation in the antebellum south in a famous novel. Okay, it means “back”. Tuatara figured a great deal in Māori culture and mythology. Much of it contradicting. On the one hand, they were descended by Punga, an angry God that caused them to be repulsive. They were feared as harbingers of bad luck. They originated when Peketula (son of Mother Earth ‘Papatūānuku’ and sky god Ranginui) made an egg of clay and brought it to the god of the forest Tāne. Tāne said “Me whakaira tangata” (give it life) and so the first tuatara was produced. On the other hand, tuataras have also been as kaitiaki or guardians.of knowledge. Talismans are often made and tuataras were often released alive near the body of a loved one so they can watch over the loved one. They are often buried under the post of the one supporting the ridge pole for places of learning and other important buildings. How do they know what to do? It is a revered creature, so do they bow down to it in reverence? Or do they go running in the complete opposite direction screaming their heads off and buying a talisman for protection? Or did a talisman seller plant the tuatara in order to get sales from panicked countrymen and women? Let us talk tuatara
Tuataras are native to New Zealand, and are long-lived, believed to be around 100 years and get to about one to three pounds and between 20-30 inches. Both males and females have spikey scales down the middle of their back and tail. They are rather dull in color - going from olive green to brown to orange-red. The males have larger spikes than the females. Unlike lizards, they don’t have external ear openings, eardrums, and a middle ear filled with sparse adipose tissue. They can only hear at low frequencies. Their eyes can focus separately and they have cells for duplex vision - they can see both during the day and at night. They have tapetum lucidum, which a lot of animals have. It’s what causes cats’ eyes to shine, And they also have nictating membranes - which is common in the animal world too - including cats and dogs. They are a translucent or clear membrane that sweeps across the eyes to protect them from dirt or are used as swimming goggles (and I bet they don’t fog!). Basically, a windshield wiper that spreads tear film along with some lymphatic fluid to remove bacteria. They are also known as the third eyelid or the haw. They are seen more commonly in cats than dogs, but if you look toward the inner eye and see a band, that is the nictating membrane. With cats, they use them when they blink or narrow their eyes. When dogs use them, it looks like they’re rolling their eyes to the back of their heads. And I know with at least cats, if they are extended across half of their eye(s), it’s a sign of either injury or illness. They are nocturnal (thought to be because that is when food is best found). Their diets are mostly insects, though they have been known to eat eggs and birds (I read where locals often see decapitated birds around.) The one prey that astonished me was the wētāpunga (also turns out to be older than the tuataras) giant wētās are often referred to as a cricket, however, they have no wings and can’t jump. The giant wētā/wētāpunga can be four inches long and weigh around 30-70 grams. They are considered the biggest insects in the world. And just for your viewing pleasure, I’m including a video!!
Tuatara also have a parietal eye, where it has a cornea, retina (with rod-like structures), lens and degenerative nerve endings going to the brain. It is not a true eye in that it can see, but by the structure, at one time it was a true eye. It is photosensitive though and it probably absorbs ultraviolet rays and in the setting of their circadian rhythm and seasonal cycles. Unlike some lizards who also have a parietal eye, the tuatara’s is covered by scales and pigments. It is only visible up until a baby turns four months old. And despite that it’s covered, it is the most advanced parietal eye of any animal that currently has them. While most reptiles shed their skin multiple times a year, a tuatara will only shed once a year. Like some lizards, most notably skinks and geckos, they have the ability of “autonomy” or dropping its tail in defense and growing it back. This is achieved because there are several “break-points” on their tails.
Reptiles depend on warm weather. They bask until they are warm enough to look for food, move around, or for metabolism so they can digest. The heat that they absorb is their source of energy. Tuatara actually likes it cooler. Anything over 77 degrees is too warm for them, and they can tolerate temperatures as low as around 40 degrees. They have special properties in their hemoglobin that allow them to hold their breath for at least an hour. Crocodilians (also animals that once saw dinosaurs) are also able to hold their breath for at least two hours, thanks to special properties in the hemoglobin. Though they use it to sit on the bottom of lakes, etc. when the weather is cooler and they go into semi-hibernation. I don’t know why tuataras need to show off. They don’t swim. Take a bite out of this!! Tuataras have unusual jaws and teeth. Their teeth aren’t like most animals, instead, they are extensions of their jaws. If they break a tooth off, it’s breaking a bone and as they get older, they have to eat softer foods because of the wear and tear of a century of living. That’s not the only thing different about their teeth. They have two rows of teeth on their upper jaw. When they bite down, the row of teeth on the bottom fit perfectly in a groove between the two rows on top. They shear their food or “saw” it to death. I’m sure their bites are extremely painful.
Some of Auckland Zoo's Tuataras
We're on tuatara time
One of the reasons why tuataras are so extremely vulnerable is that when it comes to mating, everything is s-l-o-w. They don’t even become sexually mature until sometime between 15-20 years old and don’t become their adult size until the age of 35. When males are ready to hit the town, they make themselves darker, puff up their spikes, and proudly strut in front of the female. If she’s not interested, she walks away or goes in her burrow (HARSH!) If she’s impressed, mating occurs. However, while most reptiles have two penises (called hemipenes), the tuatara have none. The male and the female have to hover until the cloacas meet and sperm can enter the female. Males can breed every year while females mate every two to five years. While fertilized and in her oviduct, the embryos can delay development. It could be so all the eggs catch up, or they have to be laid at a certain time. Called “pre-ovipositional arrest”, it can take one or two years for the eggs to develop and for her to lay them in a nest. When the mom has had enough of the bickering and fighting inside her, she will lay anywhere between 1-19 eggs and covered inside a nest she built. Incubation outside of the female can take anywhere between 12 to 15 months. Again, because they can arrest their development after they are laid. There are three different processes that can delay hatching. Embryonic diapause (the climate outside the egg isn’t suitable for hatching, or they are waiting for the dry/wet season), cold torpor (a short period where they stop when it’s too for cold developmental requirements), and delayed hatching embryonic and aestivation - state of animal dormancy - similar to hibernation during dry or hot climates. (happens towards the end, right before hatching to either/or protect themselves or to allow for the whole clutch to hatch at once, improving their survivability with numbers.) Geographical Range
At one time, they were found all over the country of New Zealand, in the millions. Then the Polynesians came and brought with them dogs and a rat species called the kiore. At first, it seemed that the two animals could coexist, but slowly the tuatara populations went down, to the point of disappearance. It turns out that the kiore were stealing eggs, and considering the very slow process. of becoming sexually mature, being carried by the female, and the length of incubation, there is no way that they could recover the numbers they had. Europeans came and brought with them cats, the Norway rat, and the ship rat. Rats certainly have a place in this country, but they are prolific breeders that have spread through every country due to white settlements, mostly. Rats eat anything and everything - including the tuatara and the wētāpunga cricket (they have been on this planet longer than tuatara) They are considered the biggest threat to native wildlife. Cats are also a problem. Cats are perfectly adapted to be the perfect predator. Domestic housecats, whether pets or feral, are responsible for about 75 extinctions worldwide, 33 of those are songbirds. They are considered invasive in any country they live in, and are not only destructive but also carry disease that can be transmitted through contact with feces. But there are also others like poaching - that has diminished because of legal status and remote locations.
New Zealand has worked hard to ensure the survival of its wildlife. In 1895 the tuataras were listed as endangered. They are now on 32 of New Zealand’s islands where the government removed non-native animals like rats, feral cats, and rabbits. As soon as they were brought back to a habitable state, native animals were reintroduced to those islands. There are roughly 100,000 in the wild today. Southland Museum and Art Gallery have been very successful in breeding tuatara for what is known as head-starting. The animals are bred in captivity and released as soon as they get big enough. This has been extremely successful. Southland Museum and Art Gallery is also well-known for a particular tuatara. Henry began living there at the age of 70. And he was not an amicable personality. At some time, he had a tumor removed from around his genitalia. At the grand old age of 111-years-old, he, along with 80-year-old girlfriend, welcomed 11 baby tuataras into this world. Neither of them remembers how it own head-starting program.]
Henry the Tuatara hanging out with Prince Harry. (I told you he hung out with royalty!) Henry was 118 at this time. As of April 2018, he was still alive.
New Zealand’s tuataras have lived on this planet for hundreds of millions of years and somehow, managed to survive, despite how long it takes to mature and hatch. Luckily, New Zealanders have embraced their national treasure. Let’s hope these precious creatures can remain. They deserve as much help as we can give them.