What closes a cat's eyes? - briefly
The nictitating membrane, also known as the third eyelid, is responsible for closing a cat's eyes. This transparent membrane protects the eye and helps maintain its health by spreading tears across the cornea.
What closes a cat's eyes? - in detail
The closure of a cat's eyes is primarily governed by two structures: the third eyelid and the nictitating membrane.
The third eyelid, also known as the nictitating membrane or haw, is an important component in feline eye protection. This structure is located at the inner corner of the cat's eye and can be seen when the cat is relaxed. The third eyelid serves multiple functions: it aids in tear production by covering the cornea to maintain its moisture, it protects the eye from irritants, and it can also indicate the cat's health status. When a cat is alert or stressed, the third eyelid may become more visible, which can be an important signal for owners and veterinarians.
Additionally, the nictitating membrane plays a significant role in eye closure. This thin, transparent tissue is connected to the third eyelid and can rapidly close over the cat's eye to protect it from potential hazards. The nictitating membrane is particularly useful during high-speed activities or when the cat encounters sudden threats, providing instantaneous protection without disrupting the cat's vision.
Furthermore, cats also have a well-developed ability to control their eyelids independently. This means that they can close one eye at a time if needed, which is an adaptation for hunting and survival. The independent movement of the eyelids allows cats to assess depth perception accurately, making them highly effective predators.
In summary, the closure of a cat's eyes is facilitated by the third eyelid and nictitating membrane, providing essential protection and contributing to the overall health and functionality of the feline eye.