Gorgeous Cat Eyes from Dexter.

CAT EYES! At our Folsom clinic we had the opportunity to safely take a picture of Dexter in his cage. As we have mentioned before, the interesting thing about domestic cats is that they really aren’t very domestic. Cats have changed very little from their origin in Africa 70,000 years ago and have made almost no changes since their domestication in the middle east 12,000 years ago. The most consistent characteristic of the cats is their crepuscular activity pattern and this means that their most active hunting period begins at dusk and continues into the night. This hunting pattern is completely dependent on cats having excellent night vision and that’s the reason for the appearance of cat eyes. When the iris of a human constricts because of bright light it goes from a large circle to a small circle. On the other hand, when a cat’s iris constricts it goes from a huge wide-open circle to a small vertical slit. The structure of the cat’s iris which can change from a narrow slit to a wide open circle allows 20X more light to be admitted to the cat eye than can be admitted into a human eye! Unfortunately, because the angle of the sun or the flash was not just right in this picture, we do not see the second great adaptation for night vision which is the yellow reflective layer INSIDE the cat’s eyes which can cause a yellow glow. The bright yellow which we do see in Dexter’s eyes is only the yellow color of the outside of the iris and that pigmentation does not contribute to the cat’s night vision.

– Geoffrey Antipa


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