Cats’ eyes are among the most unique eyes in the world. They are a true masterpiece of nature and formidable tools of vision. The eyes have vertical pupils that can open and close quickly like a camera’s aperture. Cats are nocturnal predators, meaning their eyes can adapt to both daytime and night vision. Cat’s eyes are so special that they can even glow in the dark, which leaves you wondering what else they can do. What are their adaptations? Well, I have provided reliable answers to all the questions you might have about the eyes of cats in this article.
Can cats move their eyes? No, they can’t. That’s because they lack the muscles that allow free movement of the eyeballs. They can, however, move their eyelids, change the shape of their pupils, change the size of their eyes, regulate the amount of light entering the retina, and fine-tune their vision.
Animals that can move their eyes include cattle, sheep, goats, horses, and deer. They can rotate their eyes all round depending on the position of the head. Cats, on the other hand, have limited peripheral vision, just like human beings. Their eyes face forward at the front of their face making it difficult to see the side. This can be an advantage when it comes to hunting animals. Cats use their well-adapted eyes and other features to hunt down their prey –whether in darkness or daylight. Keep reading to find out more about the adaptive features of their cats’ eyes and their functions.
Can Cats Move Their Eyes?
Cats cannot move their eyes as a whole; therefore they have to move their heads just like humans to locate anything on the sides. However, they can change them to adapt to different conditions and communicate different emotions. As mentioned earlier, they can roll their eyes, move their eyelids, blink, close their eyes, squint, dilate their pupils, and constrict them.
Below are some of the reasons why cats do the above with their eyes:
Regulate the amount of light
A cat’s large pupils constrict during the day to limit the amount of light getting into the retina. This prevents it from being dazzled by bright light because its eyes are intended for a keen night vision. The pupils narrow to a slit, allowing the cat to see clearly even in extremely bright light.
In low-light conditions, the elliptically-shaped pupils fully dilate to form sphere shapes. This allows the maximum amount of light in for better vision. This could also be a sign that the cat is scared. The pupils dilate fully so that the cat can have a wide field of vision and see more of its surroundings.
A cat’s pupils will dilate into a slit when it experiences strong emotional feelings. For instance, you might notice this in your cat as a sign of excitement when a bowl of its favourite food is presented to it. But if a new cat is introduced, your cat may become aggressive or angry. The pupils will constrict in such instances as a threat signal. When this happens, it is advisable to avoid eye contact with the cat since it takes it as a challenge to fight.
A cat opens its eyes widely when it is alert. Wide-open eyes are an indication of trust and calmness. This is because the cat would not risk exposing its eyes to harm. Therefore, if they are wide open then there is no danger or the cat trusts the object in its view.
If a cat stares at something without blinking, this is a sign of dominance or aggression. This behaviour is subtle since cats do not blink as frequently as we do. Cats do this in their territory to communicate that they are in control. It keeps other felines and even other animals away from areas of their jurisdiction. This signal is common in households that have several cats or several pets. The dominant cat will keep other animals from accessing its resources and its territory.
To have a better vision
Cats have very strong eyesight. Their eyes face forward, therefore, working together to provide a binocular vision. This allows them to have a depth perception of images in three dimensions. Using their top and bottom eyelids, cats can also move them towards each other to narrow down the image into a horizontal slit. This technique, together with narrowing their pupils vertically enables cats to fine-tune their vision with uttermost accuracy. This means that the quality of their images is usually a high definition type.
How Is The Cat’s Eye Adapted For Hunting If They Can’t Move?
Since cats are crepuscular, they have well-adapted photoreceptors for good night vision. When it comes to hunting, cats have remarkably accurate and tactful skills. They have a layer of cells called tapetum lucidum at the back that act as a mirror. The membrane reduces the threshold of a vision to around six times lower than the amount of light required for human vision. This enables the cat to see better in low light. The layer also bounces back incoming light into the retina cells so that the cat can make use of the available light. Reflection of the light is what makes the cat’s eyes glow in the dark, especially when flashed with light.
When a cat is observing prey, its focus is on the prey and not the surrounding environment. This adaptation helps when the cat is zeroing in on its prey. A cat also has many rods in its retina that act as detectors and light receptors. During hunting, the retina will detect any motion such as an animal running across its field of vision. According to scientists, a cat’s field of vision is 200 degrees while that of humans is 180 degrees. It also has an additional lateral vision on each side to aid in locating the prey.
In general, cats have very sharp eyesight. Their retina contains a very sensitive area called the area centralis, which contains thousands of photoreceptors tightly packed within it. Each photoreceptor is connected to a nerve fibre, and all the nerve fibres are put together to form the optic nerve. It is the photoreceptors that change the image into electrical impulses. The optical nerve then carries the electrical impulses to the brain. The excellent visual acuity of cats enables them to judge distance and speed accurately –something crucial for hunters.
How Do Cats Avoid Eye Injury When They Can’t Move?
Other than being adapted for sharp vision, a cat’s eye is also adapted to protect it from injury and infection. The eye is very important for all animals, yet very delicate. Cats have evolved and adapted to protect themselves from an eye injury or infection in the following ways:
Just like in humans, the cat’s eyes have upper and lower eyelids to sheathe the eyeballs from any damage. They also have a nictitating membrane –an opaque and white third eyelid that clears dust off the cornea and moistens the eye. This is why a cat doesn’t need to blink to hydrate its eyes. When sleeping, the membrane also closes to act as additional protection for the eyeballs. It moves back to the inner corner of the eye when any sound alerts the sleeping cat. The membrane is only visible from the outside in felines that sleep with their eyes partially open or when they blink.
The nictitating membrane also has a palpebral surface that faces the eyelid, and a bulbar surface facing the cornea. The palpebral surface is covered by a mucous membrane referred to as the conjunctiva and is responsible for keeping the eye moist. The bulbar surface is made up of lymphoid follicles that act as lymph nodes of the eye to trap unwanted detritus and dirt.
As in all types of eyes, a cat’s eye has a clear dome called the cornea. Just like the eyelid, it protects the eye from injury. The cornea takes the curved shape of the anterior chamber but it’s also flat with uniform thickness. It has many nerve fibres to alert the cat if it’s injured.
What Are The Limitations Of A Cat’s Vision?
Cat’s eyes need some light or illumination to function, therefore they can’t see in total darkness. The idea that they can see in the darkness is a misconception, but they can see clearer in low light when compared to human beings.
Have you ever heard that cats are colour-blind? Surprisingly, they are not. That is merely an assumption. Cats have a limited ability to distinguish colours but they are not colour-blind. They just see faded hues and fewer colours such as blue, grey, and green, but cannot perceive orange, red, or brown colours. The reason behind their partial colour blindness is that they have many eye rods but few cones. Cones detect colour while rods are light receptors. This limitation doesn’t, however, affect them because they rely on detecting motion and not finer details like colour.
Cats cannot see an object that’s more than 25 centimetres closer to them since they have a poor near vision. This can be explained by the presence of very large eyes compared to their body size. They also find it difficult to perceive objects that are at a greater distance. They cannot see clearly from about six meters. For very up close-objects, they use their whiskers for detection and location. For greater distances, they apply their sense of smell and their ability to detect tiny movements and tiny vibrations in the air.
Despite their eyes having special adaptations to the environment and for hunting, cats still have their limitations. Fortunately, they have many strongholds to nullify these limitations. They cannot move their eyes but they can cover a wide field of vision of 200 degrees, which is past half of a complete circle. Even with these few limitations, the eyes of a cat are still an amazing masterpiece of nature.