This is fascinating! Thank you so much @ferretinmyshoes for taking the time to photograph all the steps, it's so helpful to see the anatomy and learn more about our little guys!
Mechanics of a Cham cleaning their eye
- Thread starter Brodybreaux25
- Start date
The membrane can move across the visible part of the eyeball. Usually they suck the eyeball in a little as the membrane moves across it, which manually pushes debris away and lubricates the eye with tear fluid. The eyeball can move during that as well, or it can stay stationary.
I'm sure it does something for refraction of light and visual image but it hasn't been studied well enough for us to know for sure. Also it probably helps keep the turret centered over the eye where it should stay as well.
Yes, a bit disturbing.
They do have blood vessels but they are VERY tiny. Most species' eyeballs look like that for the most part because the vessels are embedded in the retina and deeper layers of conjunctiva rather than on the surface of the eyeball. But the larger the animal the larger the scleral vessels are which is why you can see them in big species like us, dogs, cats, etc.
Brodybreaux25
Chameleon Enthusiast
Do they have binocular vision?
They can transition between monocular and binocular vision. Monocular vision allows to look at things with each independently, which is why they can move separately. But they transition to binocular when hunting, which is why both eyes focus on prey at the same time.
This is a nice breakdown of it:
https://asknature.org/strategy/eyes-give-360-vision/#.W37j0naJjs0
This is a nice breakdown of it:
https://asknature.org/strategy/eyes-give-360-vision/#.W37j0naJjs0
Brodybreaux25
Chameleon Enthusiast
I worded that poorly, I ment can they zoom in and out? Pretty sure it’s a myth but figured I’d ask...
Syreptyon
Chameleon Enthusiast
Here's some peer-reviewed info for you! There is research indicating that they do have telescopic optics:
"The most unique part about the chameleon’s vision is that it is telescopic. The eyelids and lenses located within the eye are able to adjust allowing the chameleon to zoom in on objects as if it had a pair of binoculars. This gives the [...] chameleon a large advantage when it comes to spotting prey and potential predators (Holland et al., 2010)."
"[...] the optical power of the eye comes exclusively from the cornea rather than the lens. Because the cornea is further forward than the lens, the nodal (focal) point is separated from the axis of rotation of the eye. This results in increased magnification of the retinal image (the largest known for vertebrates). In other words, chameleons have long focus or telescopic vision (Pettigrew et al., 1999)"
"The most unique part about the chameleon’s vision is that it is telescopic. The eyelids and lenses located within the eye are able to adjust allowing the chameleon to zoom in on objects as if it had a pair of binoculars. This gives the [...] chameleon a large advantage when it comes to spotting prey and potential predators (Holland et al., 2010)."
"[...] the optical power of the eye comes exclusively from the cornea rather than the lens. Because the cornea is further forward than the lens, the nodal (focal) point is separated from the axis of rotation of the eye. This results in increased magnification of the retinal image (the largest known for vertebrates). In other words, chameleons have long focus or telescopic vision (Pettigrew et al., 1999)"
Brodybreaux25
Chameleon Enthusiast
It’s hard to think of another animal that has so many unique, highly specialized adaptations. They truly are incredible creatures!
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