Tuatara: Living Dinosaurs (but not really) 

Spencer Thomson 

April 18, 2025

When people think of ancient species walking the Earth, they most likely picture animals such as horseshoe crabs, clams, cockroaches, and other invertebrates. The reason these species were able to survive so long is due to their abilities to rapidly reproduce, quickly adapt to harsh and new environments, and their development of protective structures like exoskeletons or shells. But some ancient organisms are far less resilient, yet have still found ways to survive over 200 million years. One such example is the tuatara (Sphenodon punctatus). 

The tuatara is a species of reptile endemic to New Zealand, its largest native reptile. Despite their lizard-like appearance, they are not lizards but are the last surviving member of their order Sphenodontia. Sphenodontia were well established during the time of the dinosaurs, around 200-220 million years ago. However, every other member of the order went extinct around 60 million years ago, leaving the tuatara the only surviving member of an order, making them of extreme interest to biologists around the world. They used to only live in mainland New Zealand, but are now found on islands off the northern east coast of the North Island and some islands in the Marlborough Sounds. These islands are free of rodents and other mammalian predators, making it a perfect environment for them to thrive in. Their diet consists of mostly invertebrates, such as beetles, weta, worms, millipedes, and spiders. Occasionally, they will eat seabird eggs, chicks, lizards, and sometimes their own offspring. As reptiles, they are cold blooded, and need to regulate their body temperature using their external environment, and are often active in cooler weather, unusual for most reptiles. They have one of the longest growth rates of any reptile, reaching maturity between 10 and 20 years, growing to full size around 35 years, and living up to 60 years in the wild, but some are recorded to have lived for 100 years. 

Tuatara are recognized internationally as a species in need of conservation. Their isolation to the islands of New Zealand led to low genetic diversity. There are some large populations of healthy tuatara, but many small populations on smaller islands have very low genetic diversity, making them extremely vulnerable to disease and global climate change. Low genetic diversity likely makes these populations unable to adapt to severe changes in their environments. Another threat to tuatara populations is invasive species. The most prominent of these species is rats, who eat tuatara eggs and hatchlings, and compete with them for food and resources. 

Tuatara are an ideal example of an adorable, unique species that deserve protection. Worldwide, governments are trying to protect animals and plants that are in danger of extinction. Tuatara used to be endangered in New Zealand, and now are recovering and are no longer considered endangered. However, their small population still leaves them at risk for future endangerment. Although we are unable to do anything to assist them directly, it is always important to be aware of endangered species in your area and be conscious of any actions that may put any animals or plants in danger.