Do snakes blink?

Many animal species have eyelids that cover their eyes. An eyelid is a thin layer of skin covering an animal’s eye that enables it to blink. The functions of eyelids include;

• Spreading of tear film
• Contain oil glands that lessen evaporation of tears

Snakes do not have this folding layer of skin covering their eyes. Instead, a thin layer of colorless scales known as brilles or spectacles exist around their eyes that perform some of the functions of eyelids. This absence of folding eyelids thus makes it impossible for a snake to blink its eye.

Snake spectacles
Like their name suggests, the layer of colorless scales around the eye functions as spectacles. Scales are a tough layer of skin made of keratin, the same compound that finger nails are made of, covering the entire body of reptiles. During molting all the scales including those covering the cornea are shed. Before shedding of scales they are loosened from the grip of the lower skin layer hence changing color to a cloudy hue. The shed scales can be carefully examined to identify the spectacles

Snake sleep and the nocturnal pit vipers
Since snakes do not have eyelids it is almost impossible to tell when they are asleep. One way to tell if a snake is asleep is by keenly looking at its pupils. A snake’s pupil contracts when asleep. Most species of snakes are active at night and sleep or rest during the day. They are usually equipped with heat-sensing mechanisms that they use to track movements of prey by sensing the direction of their body heat.

Brilles protect snake eyes
Snakes live close to the ground where they are exposed to dust particles, grits and bits of vegetation in their faces as they move through their natural habitats. The brilles protect the cornea from scratches and damage. The thin membranes do not lie directly on the eye but are supported by a thin layer of transparent liquid that moistens the cornea.