Tuatara's Third Eye Detects Light

The tuatara is a three-eyed reptile found only in New Zealand, and it remains active at temperatures as low as 5 C (41 F). Despite its lizard-like appearance, it is the only living member of Rhynchocephalia, a reptile lineage that first appeared about 244 million years ago. Its third, or parietal, eye has a lens and retina but can detect only light rather than form images. The eye remains visible in hatchlings until scales and pigment cover it after four to six months.

Previous Fact Next Fact