What is a nickel membrane?

Many animals have a third lid called a nichened membrane. This clean lid can be drawn through the eyeball for protection from debris, prey or dry air, similar to conventional eyelids. Reptiles, birds, sharks and some mammals have developed this special layer of protection to keep their eyes wet and clean while maintaining visibility.

The nicepled membrane is part of the conjunctiva, the mucosa. It usually lies in the corner of the eye when it is not used. The nichening membrane of people is permanently folded into this corner; It's a visible pink nub. Most animals can control HAW, another name for the lid, attracting diagonally or horizontally over the cornea. When the animals evolved to live from the ocean, they had to develop a way to keep their eyeballs wet in the dry air and without particles in dusty wind. Especially predators cannot risk repeatedly with their eyes to miss a cheating mouse or a bouncing frog. The nichening membrane allows them to fully see and the benefits of flashing. Certain types of sharks willThe carchariniformes also use nickel membranes to prevent prey stab. Amphibious creatures, such as alligators, crocodiles and other reptiles, use their third lid for hunting or not underwater.

The port seal benefits from their nickel membranes because they live in and outside the water. Aardvarks close their nimtited membrane when they eat thermites to prevent bite. At the polar bear, it actually filters ultraviolet light and reduces snow blindness. Nicar membranes of other mammals, such as cats, dogs and horses, stand out only if they are sick. Visible HAW may be a symptom of semi -seyapration, tetanus, low body weight or abscess near the eye.