|Image from Wellington Zoo|
While superficially resembling lizards, there are various characteristics separating the two groups, such as lack of external ears, another set of teeth, and a developed pineal eye1. This "third eye" may help in temperature regulation, circadian regulation, Vitamin D absorption, or something completely different.
Tuataras are nocturnal and able to function at much lower temperatures than most reptiles. They have long lifespans, taking 20 years to reach maturity and living up to 100 years. Like many predators, they subscribe to the idea, "Is it animal matter, smaller than my head, and easy to catch? Then it's food." Hunting by ambush, they will eat insects, lizards, eggs, and seabird chicks.
The endangerment of the tuatara starts out fairly textbook. After millions of years isolated on islands, humans interfere and begin habitat destruction, removing them from the New Zealand mainland. Europeans bring rats, which eat the eggs and the young. However, there is a newer problem facing the tuatara. Like many reptiles, incubation temperature determines the sex of the offspring. Too warm (above 71.6 degrees Fahrenheit for the tuatara) and the nest is all males, too cold (under 69.8 degrees) and the nest is all females. What happens when global warming comes into play? One female can only parent one litter at a time (and four years apart), so this hurts the population much more than if fewer males were being hatched.
There is hope for our spiny little friends. Breeding and release programs are working on bringing the tuatara back to the New Zealand mainland, with the help of rat-proof fencing. Various studies are being conducted to determine the extent of global warming's effect.
1Though not near as developed as this guy's, who I came across while searching for images.