Cats Have a Hidden Third Eyelid
Weird

Cats Have a Hidden Third Eyelid

Cats, like most birds, fish, reptiles, and amphibians, possess a nictitating membrane — a translucent third eyelid that moves horizontally across the eye from the inner corner. Normally hidden in healthy, alert cats, it becomes visible when a cat is drowsy, ill, or under stress. Humans lost this structure through evolution.

Source

https://en.wikipedia.org/wiki/Nictitating_membrane

Details

Published
April 30, 2026
views
54