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A fact related to something in the ocean, cephalopods have photoreceptors that are oriented neatly with nerves in the back, as you would expect. But mammals have the nerves coming out the front, in the way of the path of light! [1]

So, cephalopods have sensors that match a modern camera that's "back illuminated", with metal layer/routing out of the way, and humans have a old type "front" illuminated sensor [2].

[1] Nice image here: https://www.facebook.com/groups/10150112797390640/posts/1017...

[2] https://www.digitalcameraworld.com/features/what-is-a-bsi-se...

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> reminds me of...

As long as we are already on a tangent about rods, cones, and visual perception: one of my favorite fact is that the occasional genetic mutation that creates color blindness in men sometimes leaves a woman with "tetrachromacy". Four sets of rods and cones which increases color perception from some one-million colors to one-hundred million colors.

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There was a neat story on the San Diego local news some years ago about a woman artist who was a tetrachromat. Fascinating interview. This woman said that the downside of perceiving additional colors is that something like the cereal aisle in a common supermarket could be a total sensory overload. But she of course said also that she appreciated the extra things she could see. :)
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Be thankful we're not mantis shrimp. Color displays and cameras would be such a pain to make
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Wow. That is a worth a glance, folks.
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