Body

These animals are endemic to New Zealand, with only two species still surviving. They resemble lizards but are equally related to lizards and snakes, which are their closest living relatives.

Teeth

The lower jaw has a single row of teeth, and the upper jaw has a double row of teeth. Since the teeth are projections of the jaw bone, they cannot be replaced if lost.

Third Eye

Tuataras have a third eye in the center of their forehead with a lens, retina, and cornea covered by skin. It can detect light, although color differentiation is restricted.

Hearing

With no noticeable external ears or eardrums, the hearing organs are underdeveloped and primitive and respond only to low frequencies.