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RE: Everyday, everyday, e.v.e.r.y.d.a.y is a new day.

in OCDlast year

Lizards have a photoreceptor cell on the top of their heads related to the pineal gland and hose rods and cones you were talking about. I believe it is thought to be a way for them to regulate their circadian rhythm. If you look very closely at the top of an iguanas head you will notice a dull and slightly translucent scale on their skin. That's the parietal eye.

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Yep! exactly, that's true. It should be noted that in some fishes and a lot of reptiles, amphibians and some birds, the pineal body is a formation that integrates, in addition to a simple gland, also includes photoreceptor organs whose fibers "flow" into the upper part of the skull. Like by instance, the snakes.

If you look very closely at the top of an iguanas head you will notice a dull and slightly translucent scale on their skin.

Yeah, I already knew this pretty well. We often used a small hood to cover the iguanas' heads and keep them still, while we hunted them alive and we had to submit them through some kinda rudimentary surgery to extract & remove her eggs and re-sew them again to free them alive later.

As a curious note. Due to these specific photoreceptor organs whose fibers "flow" into the upper part of the skull. That's why you can see so many alligators, crocodiles and large lizards sometimes all too often absolutely still, hunting flies and other insects (even birds) while they nap with their mouths open as if they were dead.