Features of the structure of the eyes of a cow
The cow was domesticated more than 10 thousand years ago, since then it has been a constant companion of man. She is called the nurse, in India she is revered as a sacred animal. Looking into her clever eyes, one might think that the burenka understands everything, and has remarkable intelligence, not for nothing that the expression “cow's eyes” exists. And the euphonic word “hairy” characterizing beautiful eyes comes from “eyes” and “ox”.
The structure of the organs of vision
The eyes of a cow, however, like most other mammals, consist of an eyeball and receptors - this is a kind of receiver of light waves. Then, from the “receiver”, the signal, through the optic nerve, enters the brain.
An apple, enclosed in 3 shells, is located in a special hole in the skull - the orbit.
The outer membrane consists of a cornea and a protein membrane (it is also a sclera). Fibrous tissue is the material of the inner lining.
Did you know? In addition to Hinduism, the cow was considered a sacred animal in Zoroastrianism - the ancient Persian religion (a small number of adherents of this teaching to this day lives in Azerbaijan and Iran), as well as in Ancient Egypt.
Tendons hold the protein coat. The cornea has no capillaries, but it is pierced by nerves. For this reason, the cornea of the cattle eye is highly sensitive, through it light waves enter the retina.The constituent elements of the middle shell are the ciliary body, iris and ciliary.
Pigmentation of the iris determines the color of cow's eyes. In the central part of the iris there is a pupil - a hole that has the property to change its diameter, depending on the illumination. This ability is a mechanism, a regulator of the amount of light entering the retina.
The vascular membrane is an intermediate layer between the sclera and the retina; its main function is the blood supply to the organs of vision. Between the iris and choroid, the ciliary body is located; it supports the lens and controls its curvature.
The structure of the function of the inner layer - the retina, is similar to the human organ of vision. A stream of light is reflected at the bottom of the retina, where it is converted into a nerve signal and sent to the brain.
If we simplify the functions of photoreceptors as much as possible, we can say that the main purpose of the rods is to pick up a weak light signal at night, and cones provide color perception.
The lens located in the apple is essentially a biconvex lens with a variable, due to the change in convexity, focal length. This mechanism makes it possible to see both near and far.
The vitreous body (which is based on water, only 2% of other substances), which separates the lens from the retina, forms the eye, participates in endocrine and photoconductive processes.
The organ of vision is protected from external mechanical stimuli by the upper and lower eyelids.
Due to the special shape of the pupil, the cow is able to see a sector with a viewing angle of 330 °. An animal can see objects in front of itself with two eyes at once, and switches to monocular vision if the object is located on the side (in this case, the animal sees the image with one eye without turning its head).
The most common shades of cattle eyes are black or dark brown, however, depending on the breed, the color of the eyes may be slightly different.
Important! If the calf was born with an eyesore, it can be confidently stated that during the period of intrauterine development he underwent the inflammatory process of some organ (not necessarily the eyes).
Although the structure of the organs of vision of cattle and humans is much similar, some features of cow's vision do not allow her to see the world exactly as we see it.You may have noticed that in the dark, when light hits the cow's eyes, they glow like reflectors.
This natural reflector is a special pigment covering the retina, due to which light waves of even weak strength, repeatedly reflected from the surface, create resonance, amplifying in this way. For this reason, cows are very well seen at dusk and at night.
The special substance contained in the eyes of many animals, tapetum, also contributes to night vision. However, tapetum, having the effect of reflection of light waves, and thereby helping the animal to see objects in the dark, reduces the sharpness and contrast of daytime vision.
However, some other structural features of the cattle’s organs of vision give reason to draw conclusions about the poor daytime vision of animals.Hundreds of thousands of years of evolution led to the fact that a person developed quite sharp daytime vision, thanks to which, he was able to survive among predators at the dawn of civilization, and not die of hunger, hunting during the day.
Cows don’t have such a need, the ancestors of modern bogies, in the wild in the daytime, could find grass and water with poor eyesight. It was much more important to have keen night vision in order to see the impending danger.
And after the man domesticated the cattle, they no longer need acute vision, since people took responsibility for the safety of their nurse.
Did you know? Many people paid attention that the burenka can calmly stand on a leash, chew gum, pinch grass, and suddenly, it jerks sharply, as if frightened, from the sudden approach of a person, sometimes even a friend. This is a fright, but it is simply explained: the cow sees all objects not life-size, one of the features of her vision is the transmission of an enlarged image to the brain.
Are color blinds cows
The location of the photoreceptors in the eyes of the cows, suggests that she distinguishes the primary colors, although not as clearly as we are. About any difference in the shades of speech does not go. Color blindness can be inherited, or (much less commonly) developed in an animal whose ancestors normally distinguished colors.
It should be said that some special reaction to the red color (the famous bullfighting) in bulls is nothing more than a legend; cattle reacts to red and its shades in the same way as to other colors.It is not the color that irritates the animal, but the mechanical movement of the obstacle in front of it (the bullfighter shakes his cloak, the animal perceives the cloak not as a piece of fabric, but as a barrier, an obstacle that, moreover, shakes).
And the red color of the cloak is due only to the drama of the show. Firstly, this color is clearly visible from afar, and secondly, the combination of red and black (the suit of the bull) is generally a classic, and, of course, it could not do without some symbolism, because red, first of all, is the color of blood.
Possible eye diseases
Cows are quite susceptible to diseases of the organs of vision.
The etiology of diseases can be completely different:
- injuries of mechanical or chemical origin (for example, fertilizers or herbicides with open grazing);
- complications after other diseases.
Important! Due to poor living conditions, cattle can develop a parasitic disease, teliasis, which, in turn, is often the cause of the appearance of eyesore in the cows. To avoid this, it is necessary to thoroughly clean the waste products and dirt in the barn. You should also handle the room from flies, which are the main carriers of the disease.
We can say that there is nothing supernatural in the organs of vision of a cow, there are only some features of the structure of the eye that are characteristic of this species.