Phyla: The Tuatara

This New Zealand animal resembles a lizard but is actually considered a separate order. What makes it interesting is the fact that it has a "third eye" on the top of it's head. The use of this eye-derived spot is unknown, but there are theories concerning it's use as a thermoregulating agent and for vitamin D absorption.
There are only two species of tuataras worldwide. Measuring up to 23 inches in length and weighing up to 3 pounds the tuatara spends alot of it's time basking and is mostly nocturnal. They are insectivorous but may prey on small lizards and bird eggs when available. Their coloration varies from dark greens and browns to light. On males, a distinctive crest, for which the reptile is named, can be seen.
Tuatara's grow incredibly slowly, due to a reduced metabolism. It may take up to 20 years to reach sexual maturity. They also breath as little as once an hour depending on their activity level. Though they grow slowly they can live a very long time(100 years speculatively).

     The tuatara's cranium differs from lizards' because the upper jaw is attached to the skull, it's teeth are actually points of jaw bone rather than individual teeth, they have two rows of teeth on top and one on the bottom, and they have no eardrums. Normal tropical temperatures, that suit many lizards, can be fatal to tuatara's, who prefer cooler climates (as low as 41 degrees Fahrenheit).
     As for mating, not only do they take a long time to reach sexual maturity, but they only mate once every 4 years. The male does not have sex organs, but instead mates as salamanders do, by pore to pore transfer of gametes. Once copulation takes place the egg must reside inside it's mother for a year to develop the yolk sac. The eggs must then be laid and then need up to a year to hatch. As with other reptiles the temperature of the eggs determines the sex of the offspring. At 64 degrees Fahrenheit and higher, all the young will be females, any lower and males will develop.
     Tuataras are protected by law. They are sensitive to climate changes and are threatened by land predators such as rats and snakes. Rats have had to be eradicated on some islands to promote the welfare of this reptile. There are also many captivly bred tuatara's to ensure survival.

Not only are tuataras delicate but they hold a significance to the native people of New Zealand, the Maori's. Maori culture relates tuataras to the god of death and disaster as well as the boundary between sacred and restricted.