Parietal Eye

Some lizards, like iguanas and Bearded Dragons, have whats called a Parietal Eye. This 'third-eye' is not a traditional eye, but is a photosensory organ located on the top of their heads and is connected to the the lizards pineal gland.

The Parietal Eye detects changes in light with its very basic lens and retina. This allows the lizard to properly thermoregulate their body, and is why proper light cycles in captivity are important.

Second to thermoregulation, the Parietal Eye also acts as a defensive measure for lizards, since an approaching predator will cause the light to change.

Example of Parietal Eye

The parietal eye of a Green Anole. The anole has obviously changed color.

Photo Credit: TheAlphaWolf, License: Creative Commons Attribution-Share Alike 3.0 Unported



