Iguana Anatomy
Dewlap, Teeth, Femoral Pores, Tail, Brain Bumps, Subtympanic Scale, Ear, Rostral Horns, Parietal Eye

In this next photo, the blue circle shows Mary's rostral horn (which was in the process of falling off after an injury); the red circle shows the subtympanic scale, which is the large scale located under an iguanas ear; and the yellow circle shows the ear itself.




Located on the top of the head between the "brain bumps" is a spot known as the parietal eye, sometimes called the "third eye". The parietal eye is not an eye in the traditional sense in that it does not see images, but rather is a photosensitive organ which only reacts to light and dark. The parietal eye is connected to the iguana's pineal body and is used to trigger hormone production and thermoregulation. In most iguanas, the parietal eye shows up as either a dark spot or an opalescent spot. In these photos of Bailey and Mary, you can see that Bailey has a dark parietal eye while Mary has the opalescent kind.



is a photosensory organ connected to the pineal body, active in triggering hormone production (including reproduction) and thermoregulation. It is sensitive to changes in light and dark, it does not form images, having only a rudimentary retina and lens. It is visible as an opalescent gray spot on the top of some lizard's heads; also referred to as "pineal eye" or "third eye."