Since cats are predators by nature, they need excellent eyesight to see and chase prey not only during the day, but also at night. To understand how a four-legged friend sees, you need to know about the physiological structure of the eyes and the peculiarities of perception of the external world.
The structure of the eye
Cats have always been considered excellent night hunters. The anatomy and physiology of the visual organs were formed in the course of evolutionary development. For cats, it is important to track down prey and navigate in the dark. That is why the anatomical structure of the visual organs of cats is designed in such a way that they are able to distinguish objects in low light.
The structure of a cat’s eye consists of three main parts. And each part has its own functional features:
The outer fibrous part – the outer fibrous shell, called the sclera, has a convex shape that resembles a ball. It occupies three-quarters of the back surface of the eye, and another four-quarters is occupied by the cornea – a transparent thin cell layer that transmits light beams to the eye organ;
It is located in the middle part of the cat’s eye. This is a collection of blood vessels and capillaries that transport oxygen and nutrients to all eye tissues.At the point where the sclera and cornea connect, the ciliary body is located. It is controlled by the ciliary muscle, which holds the lens of the eyeball in a certain position. This muscle can tense and relax depending on the cat’s attention and the location of the object. Under the influence of this movement of the muscle, the lens changes its shape. This process is called accommodation.The iris is located on the front of the choroid, and divides the front of the cat’s eye into two chambers – the front and back. In the center of the iris is the pupil. It changes its shape depending on the light flow-it narrows in bright daylight, expands in dim light;
The inner part or retina
It consists of photoreceptors that transform light signals into electrochemical ones. It also transmits the received information to the nervous system. In the retina of the eye there is an optical disk or, as it is also called, a “blind spot” – an opening through which blood vessels and the optic nerve exit. Compared to other parts of the retina, the optical disk does not have photoreceptors.In turn, photoreceptors are divided into rods and cones. In four-legged Pets, sticks are considered the most developed, since their main function is increased sensitivity to minimal light flows at night. The function of the cones is to recognize the color and clarity of the image in the daytime.
Cat and human vision. What are the differences?
Some people believe that cats can see perfectly in absolute darkness, but this is not the case. Furry Pets, like people, in the complete absence of light do not see anything. But with minimal light, they are able to recognize objects much better in the dark.
In humans, the ratio of rods to cones is 4 to 1. And a cat has 25 times more sticks than cones. This leads to the fact that cats prefer a nocturnal lifestyle.
In the daytime, cats are able to clearly distinguish objects at a distance of up to 20 m, and people up to 40 m. In addition, cats do not see objects that are at close range, and determine them mainly based on their olfactory senses.
Night and color vision
At night, with minimal light, cats are 15 times better at distinguishing objects than humans. Of course, for successful hunting, small predators also connect other senses, such as hearing and smell.
The human eye perceives all colors, but the cat’s eye can only see:
- gray and its shades.
Green, red, brown and orange colors do not differ for a cat.
The main features of cat vision include:
- Changing the pupil depending on the light. This feature helps to regulate the light beams that fall on the retina.
- Behind the retina is a layer of tapetum. It is a “mirror” and reflects light. Thus, the light beam, falling on the retina of the eye, penetrates the tapetum, is reflected and re-enters the retina. Thus, the cells of the eye receive a double stream of light, which increases the cat’s night vision. And the glowing eyes of Pets in the dark are also caused by the tapetum layer.
Do cats perceive movement on TV?
Some scientists suggest that cats, looking at the TV screen, see only some movement of objects. However, zoologists give such an example – when a cat sees a program about animals, it closely follows what is happening on the screen, and when the program ends, the pet loses all interest in the TV.
Other scientists believe that cats see the video image on the screen in the form of pictures. This is explained by the fact that Pets perceive 40 frames per second, and people only 24. And since the TV is tuned to human vision, animals can only perceive what they see as changing images.
The visual acuity of Pets in relation to human is 20/75, i.e. the same object cats will see well from 20m, and people – from 75m. Standard TVs with a frequency of 50 Hz create flickering. New LCD TVs operate at a higher frequency – 100 Hz, and most cats would prefer to watch this type of TV.
But the animals perceive their reflection in the mirror as a fellow animal and actively begin to attack it. But since the animal does not feel any smell or tactile additional sensations and cannot compare the inappropriate information received with the established representation, it simply ignores the image.
Vision for cats is the main tool for survival. The predator, thanks to its sharp eyesight, can track prey not only during the day, but also at night. Knowing this, you can explain the nocturnal activity of cats.
Hi, my name is Mike Fletcher. I am 36 years old and a veterinarian at a veterinary clinic in Granby Colorado. And this is my blog about Pets. I hope I can answer your questions here.