All mammals have well-developed vision. Features of the organization of mammals

Man is the highest intelligent being on Earth, but some of our organs are significantly inferior to our smaller brothers, one of which is vision. At all times, people have been interested in how the world around us Birds, animals, insects see, because outwardly everyone’s eyes are so different, and today’s technologies allow us to look through their eyes, and believe me, the vision of animals is very interesting.

Such different eyes

Animal eyes

The first thing everyone is interested in is - how do our closest friends see us?

Cats have excellent vision pitch darkness, since their pupil can expand up to 14 mm, thereby capturing the slightest light waves. In addition, they have a reflective membrane behind the retina, which acts as a mirror, collecting all the particles of light.

Cat pupils

Due to this, a cat sees in the dark six times better than a human.

In dogs, the eye is structured in approximately the same way, but the pupil is unable to expand as much, thereby giving it a fourfold advantage over humans to see in the dark.

What about color vision? Until recently, people were sure that dogs see everything in shades of gray, not distinguishing a single color. Recent studies have proven this to be a mistake.

Dog color spectrum

But you have to pay for the quality of night vision:

1. Dogs, like cats, are dichromats; they see the world in faded blue-violet and yellow-green colors.
2. Visual acuity is poor. In dogs it is about 4 times weaker than ours, and in cats it is 6 times weaker. Look at the Moon - do you see spots? Not a single cat in the world sees them; for her they are just a gray spot in the sky.

It is also worth noting the location of the eyes in animals and in us, due to which pets see with peripheral vision no worse than with central vision.

Central and peripheral vision

Another interesting fact– dogs see 70 frames per second. When we watch TV, 25 frames per second for us merge into a single video stream, but for dogs it’s a quick series of pictures, which is probably why they don’t really like watching TV.

Except dogs and cats

A chameleon and a seahorse can look at the same time different sides, each of his eyes is processed separately by the brain. Before throwing out its tongue and grabbing the victim, the chameleon still closes its eyes to determine the distance to the victim.

But an ordinary pigeon has a viewing angle of 340 degrees, which allows you to see almost everything around, which makes hunting difficult for cats.

A few dry facts:

• Deep-sea fish have a super-dense retina, with 25 million rods concentrated on every millimeter. This exceeds ours a hundred times;
• A falcon sees a mouse in a field from a distance of one and a half kilometers. Despite its flight speed, clarity is completely preserved;
• The scallop has about 100 eyes on the edge of its shell;
• The octopus has a square pupil.

The reptiles outdid everyone a bit. Pythons and boas can see infrared waves, that is, warm! In a sense, we also “see” it with our skin, but snakes see it with their eyes, like the predator in the film of the same name.

Mantis shrimp

But the mantis shrimp have the most unsurpassed eyes. These are not even eyes, and an organ stuffed with wave sensors. Moreover, each eye actually consists of three - two hemispheres separated by a stripe. Visible light is perceived only by the middle zone, but the hemispheres are sensitive to ultraviolet and infrared ranges.

Shrimp sees 10 colors!

This does not take into account the fact that the shrimp has trinocular vision, in contrast to the most common on the planet (and in our country) binocular vision.

Insect eyes

Insects can also surprise us a lot:

• It is not so easy to kill an ordinary fly with a newspaper, since it sees 300 frames per second, which is 6 times faster than us. Hence the instant reaction;
• A domestic cockroach will see movement if the object has moved only 0.0002 millimeters. This is 250 times thinner than a hair!
• The spider has eight eyes, but in fact they are practically blind insects, capable of distinguishing only a spot; their eyes practically do not work;
• A bee's eye consists of 5,500 microscopic lenses that do not see red;
• The earthworm also has eyes, but atrophied ones. He can distinguish day from night, nothing more.

Bee eyes

The most sharp vision Among insects, dragonflies have it, but it is still about 10 times worse than ours.

What kind of vision do animals have, visual video

How do our four-legged friends see?

Until now, we, the owners of our four-legged pets, know practically nothing about their vision. Do our cats and dogs see colors? How do they see the world around them? Are dogs really nearsighted and cats, on the contrary, farsighted? Is it true that animals can see into the distance? worse than a man? All these interesting and entertaining questions are answered by the Head of the Center for Veterinary Ophthalmology, Associate Professor Alexey Germanovich Shilkin and his colleagues.

I want to say right away that humans and animals see the world around them completely differently and have different eye structures. A person receives more than 90% of information about the world around him through vision. It is not only the most important, but also the dominant one among the other senses. Our vision has excellent sharpness far and near, a wide range of colors, and this is due to the fact that in the human eye there is a functional center of the retina - the macula. The human eye, through the refractive system: cornea, pupil and lens, directs the entire flow of light into the eye to the macula.

Human visual system.

The human optical system focuses the visual image into the macula - central part eyes, where is the most large number light-sensing cone receptors. This forms the macular - central vision person.

Here are the photoreceptors - cones, with the highest visual activity. The denser their concentration, the higher visual acuity. Moreover, each cone through the fibers optic nerve has its representation in the central nervous system. It looks like a high resolution matrix.

In our optic nerve it passes simply huge amount nerve fibers– more than 1 million 200 thousand. All information from the eye passes to the visual area of ​​the cerebral cortex, where unusually developed higher cortical centers. By the way, the old Russian proverb that we see not with our eyes, but with the back of our heads in the light of modern knowledge is not without meaning.

Human fundus

1. The optic disc, consisting of 1 million 120 thousand nerve fibers, provides high visual resolution.
2. Macula( maculae), is the functional center of the human retina, due to the large number of nerve fibers, provides high visual acuity and full perception flowers.
3. The vessels of the retina are arteries and veins.
4. The periphery of the retina is represented by rods that do not fit tightly to each other. Due to this, a person’s vision in the dark is weak.

The yellow spot is characteristic only of humans and a number of higher primates. Other animals do not have it. Several years ago, American scientists compared the vision of humans and monkeys. Studies have shown that monkeys see better. Then similar experiments were carried out between a dog and a wolf. Wolves, as it turns out, see better than our pets. This is probably some kind of retribution for all the benefits of civilization.

How do animals' eyes work?

Our four-legged pets perceive everything a little differently. For dogs and cats, vision is not decisive in the perception of the world around them. They have other well-developed senses: hearing, smell, touch, and use them well. The visual system of animals has some interesting features. Dogs and cats see equally well in the light and in the dark. It should be said that the size of the eyes of animals practically does not correlate with the size of the body. The size of the eye depends on whether the animal is diurnal or nocturnal. Nocturnal animals have larger and protruding eyes, unlike daytime animals.

The size of an animal's eyes does not depend on body size. All nocturnal birds have huge bulging eyes, which help them navigate perfectly in the dark.

For example, an elephant’s eyes are only 2.5 times larger than those of a cat. Animals do not have a macula, the functional center of vision. What does this give them? If a person sees predominantly with a yellow spot and has central type vision, then dogs and cats see equally with the entire retina and have a panoramic type of vision.

The visual system of the animal eye.

The optical system of animals uniformly directs the visual image across the entire surface of the retina, thereby creating panoramic vision. Thus, the entire retina of animals sees equally.

The retina of dogs and cats is divided into 2 parts. The upper “tapetal” part shines like mother-of-pearl and is intended for vision in the dark. Its color varies from green to orange and directly depends on the color of the iris. When in the dark we see shining green eyes cats, we just observe the green fundus reflex. And the eyes of wolves, glowing at night with an ominous red color, are nothing more than the colored tapetal part of the retina

Fundus of a dog.

1. The optic disc consists of 170 thousand nerve fibers. Due to this, animals have a lower resolution of visual images.
2. Bottom part retina - pigmented. The pigment protects the retina from burns by ultraviolet radiation (spectrum) of daylight.
3. Retinal vessels.
4. Animals have a reflective shiny membrane (tapetum lucidum). Due to its presence, animals (especially those leading a nocturnal lifestyle) see much better in the dark.

The lower part of the retina is pigmented. She brown and is adapted for vision in light. The pigment protects the retina from damage from the ultraviolet part of the solar spectrum. The large bulging eye and the division of the retina into two halves create all the conditions for life with wide range illumination And panoramic vision helps animals hunt better and stay ahead of prey.

What is the visual acuity of animals?

While gaining in panoramic vision and the ability to adapt in a wide range of the spectrum, animals are inferior to humans in visual acuity. According to the literature, dogs see 30%, and cats 10% of human visual acuity. If dogs could read, at a doctor’s appointment they would read the third line from the top (from the table that you all saw), and cats would only read the first. A person with 100% normal vision reads the tenth line. This is due to the absence of a yellow spot in dogs and cats. In addition, light-perceiving photoreceptors are located at a great distance from each other, and the number of nerve fibers in the optic nerve of animals is 160-170 thousand, which is six times less than in humans. The visual image seen by animals is perceived by them less clearly and with low detailed resolutions.

Are dogs really nearsighted and cats farsighted?

This is a widespread misconception, even among veterinarians. We spent special studies in 40 animals by measuring myopia and farsightedness. To do this, dogs and cats were seated in front of an autorefractometer (as at an appointment with a human ophthalmologist) and the refraction of the eye was automatically measured. We have found that dogs and cats do not suffer from myopia and farsightedness, unlike humans.

Why do dogs and cats play with moving objects?

We humans see stationary objects better and we owe this to cones. Dogs and cats have predominantly rod vision, and rods are better at perceiving moving objects than stationary ones. So, if animals see a moving object from a distance of 900 meters, then they see the same object in a stationary state only from a distance of 600 meters and closer. As soon as the bow on the string or the ball begins to move, the hunt has begun!

Do our pets see colors?

A person distinguishes colors perfectly due to the cones, which have the greatest density in the area of ​​the macula. Until recently, it was believed that if animals do not have a yellow spot, then they see the world in black and white. Discussions about the ability of animals to distinguish colors have been going on for more than a century. All sorts of experiments were carried out to refute each other. Researchers shined flashlights into eyes different colors and tried to understand by the degree of constriction of the pupil which of the colors there was a greater reaction to.

The end to these disputes was put at the end of the 80s by American researchers. The results of their experiments showed that dogs distinguish colors, but unlike humans, their color palette is much poorer.

The eyes of animals contain significantly fewer cones than those of humans. The human color palette is formed from cones three types: The first perceives long-wavelength colors - red and orange. The second type perceives mid-wave colors better - yellow and green. The third type of cones is responsible for short-wavelength colors - blue and violet. Dogs do not have the cones responsible for the color red. Thus, dogs generally perceive well the blue-violet and yellow-green range of colors. But animals see up to 40 shades of gray, which gives them undeniable advantages when hunting.

How do animals navigate in the dark?

Dogs are 4 times better and cats are 6 times better at seeing in the dark than humans. This is due to two reasons.

Animals have more sticks, compared to humans. They are located along the optical axis of the eye, and have high photosensitivity and are better suited for vision in the dark than human rods.

In addition, animals, unlike humans, have a highly active reflective membrane, tapetum lucidum. It greatly improves the visual abilities of animals into the distance in the dark. Its role can be compared to the silver coating of a mirror or the reflections of a car headlight. The reflective membrane in dogs is represented by guanine crystals located in the upper part behind the retina.

Dog reflective membrane (tapetum lucidum).

The reflective membrane works as follows. In the dark, in dogs, each quantum of light passing through the transparent retina reaches the reflective membrane and, reflected from it, hits the retina again. Thus, a significantly greater light flux reaches the retina, and surrounding objects become more visible in the absence of light.

A gang of cats with glow-in-the-dark eyes. Cats eyes glow green due to the presence of a reflective membrane. In wolves it is red, and therefore in the dark, wolves' eyes glow “ominous red.”

In cats, reflective crystals also increase image contrast by changing the wavelength of the reflected color to the optimal one for photo receptors.

Width of visual fields of humans and animals

One more important characteristic is the width of the field of view. A person's eye axes are parallel, so he sees best straight ahead.

This is how a person sees the image.

The dog's eyes are positioned so that their optical axes diverge by about 20 degrees.

The human eye has a field of vision in the form of a circle, while the field of vision of a dog is “stretched” to the sides. Due to the divergence of the eye axes and “horizontal stretching,” the dog’s total field of vision increases to 240-250 degrees, which is 60-70 degrees more than that of a person.

A dog's field of vision is much wider than that of a human.

But these are average figures, the width of the fields of view varies depending on different breeds dogs. The structure of the skull, the location of the eyes, the shape and size of the nose have an influence. In wide-faced dogs with a short nose (Pekingese, pug, English bulldog), the eyes diverge at a relatively small angle. Therefore, they have limited peripheral vision. In narrow-faced dogs with an elongated nose (greyhounds and other hunting breeds), the axes of the eyes diverge at a large angle. This gives the dog a very wide field of vision. It is clear that this quality is very important for successful hunting.

A horse's field of vision significantly exceeds not only a human's, but also a dog's.

Thus, our pets see the world very differently. Dogs and cats see much better than us in the dark, have a wider field of vision, and perceive moving objects better. All this allows our pets to hunt perfectly and evade pursuit, to see not only in front of them, but also to the sides. At the same time, they are inferior to us in visual acuity and the ability to subtly distinguish colors. But animals don’t need this, they don’t read books until... We’ll see what happens next.

We see the world around us and it seems to us that it is exactly like this. It’s hard to even imagine that someone sees it differently, in black and white, or without blue and red. It’s hard to believe that for some people our familiar world is completely different.

But that's exactly how it is.

Let's look at the world around us through the eyes of animals, let's figure out how animals see, in what colors they perceive the world.

So, first, let's look at what vision is and what functional abilities it includes.

What is vision?

Vision is the process of processing images of objects in the surrounding world.

• carried out visual system
• allows you to get an idea of ​​the size, shape and color of objects, their relative position and the distance between them

The visual process includes:

• penetration of light flux through the refractive media of the eye
• focusing light on the retina
• transformation of light energy into nerve impulse
• broadcast nerve impulse from the retina to the brain
• processing information with the formation of a seen image

Visual functions:

• light perception
• perception of moving objects
• field of view
• visual acuity
• color perception

Light perception is the ability of the eye to perceive light and determine varying degrees of its brightness.

The process of adaptation of the eye to different conditions lighting is called adaptation. There are two types of adaptation:

• to darkness - when the light level decreases
• and to light - with increasing light levels

Light perception is the basis of all forms of visual sensation and perception, especially in the dark. The light perception of the eye is also influenced by such factors as:

• distribution of rods and cones (in animals, the central region of the retina at 25° consists predominantly of rods, which improves night vision)
• concentration of light-sensitive visual substances in rods (in dogs, the sensitivity to light of rods is 500-510 nm, in humans 400 nm)
• the presence of tapetum (tapetum lucidum) - a special layer choroid eyes (the tapetum directs photons back to the retina, causing them to once again act on the receptor cells, increasing the light sensitivity of the eye, which in low light conditions turns out to be very valuable) in cats, the eye reflects 130 times more light than in humans (Paul E. Miller, DVM, and Christopher J. Murphy DVM, PhD)
• pupil shape - the shape, size and position of the pupil in various animals (the pupil can be round, slit-like, rectangular, vertical, horizontal)
• the shape of the pupil can tell whether an animal is a predator or a prey (in predators the pupil narrows into a vertical stripe, in preys into a horizontal stripe - scientists discovered this pattern by comparing the shapes of the pupils in 214 species of animals)

So, what are the different pupil shapes:

How do animals perceive moving objects?

The perception of movement is vital important, because moving objects are signals of either danger or potential food and require quick appropriate action, while stationary objects can be ignored.

For example, dogs can recognize moving objects (due to a large number of rods) at a distance of 810 to 900 m, but stationary objects only at a distance of 585 m.

How do animals react to flickering light (for example, on TV)?

The response to flickering light provides insight into the function of the rods and cones.

Human eye capable of detecting vibrations of 55 hertz, and dog eye picks up vibrations at a frequency of 75 hertz. Therefore, unlike us, dogs most likely see only flickering and most of them do not pay attention to the image on TV. Images of objects in both eyes are projected on the retina and transmitted to the cerebral cortex, where they are merged into one image.

What are the visual fields of animals?

Field of view is the space perceived by the eye with a fixed gaze. There are two main types of vision:

• binocular vision - perception of surrounding objects with both eyes
• monocular vision - perception of surrounding objects with one eye

Binocular vision is not present in all species of animals and depends on the structure and relative position of the eyes on the head. Binocular vision allows you to make fine coordinated movements of the forelimbs, jumping, and move easily.

For predators, binocular perception of hunting objects helps them correctly assess the distance to the intended victim and choose the optimal attack trajectory. In dogs, wolves, coyotes, foxes, jackals, the binocular field angle is 60-75°, in bears it is 80-85°. In cats, 140° (the visual axes of both eyes are almost parallel).

Monocular vision with a large field allows potential victims (marmots, gophers, hares, ungulates, etc.) to notice the danger in time. reaches 360° in rodents, 300-350° in ungulates, and more than 300° in birds. Chameleons and seahorses can look in two directions at once, because... their eyes move independently of each other.

Visual acuity

• the ability of the eye to perceive two points located at a minimum distance from each other as separate
• the minimum distance at which two points will be visible separately depends on the anatomical and physiological properties of the retina

What does visual acuity depend on?

• on the size of the cones, the refraction of the eye, the width of the pupil, the transparency of the cornea, lens and vitreous(make up the light refractive apparatus), states retina and optic nerve, age
• The diameter of the cones determines the value of maximum visual acuity (the smaller the diameter of the cones, the greater the visual acuity)

Visual angle is the universal basis for expressing visual acuity. The normal sensitivity limit of the eye of most people is 1. In humans, to determine visual acuity, the Golovin-Sivtsev table is used, containing letters, numbers or signs of various sizes. In animals, visual acuity is determined using (Ofri., 2012):

• behavioral test
• electroretinography

The visual acuity of dogs is estimated at 20-40% of the visual acuity of humans, i.e. a dog recognizes an object from 6 meters, while a person recognizes an object from 27 meters.

Why doesn't a dog have the visual acuity of a human?

Dogs, like all other mammals except monkeys and humans, lack the central fovea of ​​the retina (the area of ​​maximum visual acuity). Most dogs are slightly farsighted (hyperopia: +0.5 D), i.e. they can distinguish small objects or their parts at a distance of no closer than 50-33 cm; all objects located closer appear blurry, in circles of dispersion. Cats are nearsighted, meaning they cannot see distant objects as well. The ability to see well up close is more suitable for hunting prey. The horse has low visual acuity and is relatively myopic. Ferrets are myopic, which is, no doubt, a reaction to their adaptation to a burrowing lifestyle and searching for prey by smell. Ferrets' nearsighted vision is as sharp as ours and maybe even a little sharper.

Thus, the eagle has the sharpest vision, then in descending order: falcon, man, horse, dove, dog, cat, rabbit, cow, elephant, mouse.

Color vision

Color vision- this is the perception of the color diversity of the surrounding world. All light part electromagnetic waves creates a color spectrum with a gradual transition from red to violet (color spectrum). Color vision is carried out by cones. There are three types of cones in the human retina:

• the first perceives long-wavelength colors - red and orange
• the second type perceives mid-wave colors better - yellow and green
• the third type of cones is responsible for short-wavelength colors - blue and violet

Trichromasia - the perception of all three colors
Dichromasia - seeing only two colors
Monochromacy - seeing only one color

How do animals perceive color?

Animal type	Short length waves, nm	Average wavelength, nm	Source
Dog	454	561	Loop et al. (1987) Guenther & Zrenner (1993)
Cat	429-435	555	Neitz et al. (1989); Jacobs et al. (1993)
Horse	428	539	Carroll et al. (2001); Timney&Macuda (2001)
Pig	439	556	Neitz&Jacobs (1989) Cow 451 555 Jacobsetal. (1998)

Color vision in dogs:

Color vision of cats:

Horse color vision:

Eyes are a special organ that is endowed with all living beings on the planet. We know in what colors we see the world, but how do animals see it? What colors do cats see and what colors do they not? Do dogs have black and white vision? Knowledge about animal vision will help us take a broader look at the world around us and understand the behavior of our pets.

Features of vision

And yet, how do animals see? According to certain indicators, animals have more advanced vision than humans, but it is inferior in the ability to distinguish colors. Most animals see only in a palette specific to their species. For example, for a long time it was believed that dogs see only in black and white. And snakes are generally blind. But latest research proved that animals see different lengths waves, unlike humans.

Thanks to vision, we receive more than 90% of the information about the world that surrounds us. The eyes are our predominant sensory organ. It is interesting that the sharpness of animal vision is significantly higher than that of humans. It's no secret that feathered predators see 10 times better. An eagle is able to detect prey in flight from a distance of several hundred meters, and a peregrine falcon tracks a pigeon from a height of a kilometer.

Another difference is that most animals have excellent vision in the dark. Photoreceptor cells in the retina of their eyes focus light, and this allows nocturnal animals to capture streams of light of several photons. And the fact that the eyes of many animals glow in the dark is explained by the fact that under the retina there is a unique reflective layer called tapetum. Now let's take a look individual species animals.

Horses

The gracefulness of the horse and its expressive eyes are unlikely to leave anyone indifferent. But often those who learn to ride are told that approaching a horse from behind is dangerous. But why? How do animals see what is happening behind them? No way - it’s behind the horse’s back and therefore it can easily get scared and buck.

The horse's eyes are positioned so that it can see from two angles. Her vision is, as it were, divided in two - each eye sees its own picture, due to the fact that the eyes are located on the sides of the head. But if the horse looks along the nose, then it sees one image. This animal also has peripheral vision and sees excellently at dusk.

Let's add a little anatomy. The retina of any living creature contains two types of receptors: cones and rods. Color vision depends on the number of cones, and rods are responsible for peripheral vision. In horses, the number of rods exceeds that in humans, but the cone receptors are comparable. This suggests that horses also have color vision.

Cats

Many people have animals at home, and the most common are, of course, cats. The vision of animals, and especially of the cat family, differs significantly from that of humans. A cat's pupil is not round, like most animals, but elongated. It reacts sharply to large amounts of bright light by narrowing to a small gap. This indicator says that in the retina of the animal’s eye there is a large number of rod receptors, due to which they see perfectly in the dark.

What about color vision? What colors do cats see? Until recently, it was believed that cats see black and white. But studies have shown that it distinguishes gray, green and blue colors well. In addition, it sees many shades of gray - up to 25 tones.

Dogs

Dogs' vision is different from what we are used to. If we return to anatomy again, there are three types of cone receptors in the human eye:

• The first perceives long-wave radiation, which distinguishes orange and red colors.
• The second is medium wave. It is on these waves that we see yellow and green.
• The third, accordingly, perceives short waves at which blue and violet are distinguishable.

Animals' eyes are distinguished by the presence of two types of cones, so dogs do not see orange and red colors.

This difference is not the only one - dogs are farsighted and see moving objects best. The distance from which they see a stationary object is up to 600 meters, but dogs notice a moving object from 900 meters. It is for this reason that it is best not to run away from the four-legged guards.

Vision is practically not the main organ of a dog; for the most part, they follow smell and hearing.

Now let's summarize - what colors do dogs see? In this they are similar to colorblind people; they see blue and violet, yellow and green, but a mixture of colors may seem simply white to them. But dogs, like cats, are best at distinguishing gray colors, and up to 40 shades.

Cows

Many believe, and we are often told, that domestic artiodactyls react strongly to the color red. In reality, the eyes of these animals perceive the color palette in very blurry, fuzzy tones. That's why bulls and cows respond more to movement than to how your clothes are colored or what color is waved in front of their face. I wonder, who will like it if they start waving some kind of rag in front of their nose, sticking spears into the back of their neck?

And yet, how do animals see? Cows, judging by the structure of their eyes, are able to distinguish all colors: white and black, yellow and green, red and orange. But only weakly and blurry. Interestingly, cows have similar vision magnifying glass, and it is for this reason that they are often frightened when they see people unexpectedly approaching them.

Nocturnal animals

Many nocturnal animals have, for example, tarsier. This is a small monkey that comes out to hunt at night. It is no larger than a squirrel, but it is the only primate in the world that feeds on insects and lizards.

The eyes of this animal are huge and do not rotate in their sockets. But at the same time, the tarsier has a very flexible neck, allowing it to rotate its head a full 180 degrees. He also has extraordinary peripheral vision, allowing him to see even ultraviolet radiation. But the tarsier distinguishes colors very poorly, like everyone else

I would also like to say about the most common inhabitants of cities at night - bats. For a long time it was assumed that they do not use vision, but fly only thanks to echolocation. But recent studies have shown that they have excellent night vision, and what's more - bats able to choose whether to fly towards the sound or turn on night vision.

Reptiles

While talking about how animals see, one cannot remain silent about how snakes see. The fairy tale about Mowgli, where a boa constrictor captivates the monkeys with his gaze, leaves you in awe. But is this true? Let's figure it out.

Snakes have very poor eyesight, which is affected by containment, covering the eye of a reptile. This makes the named organs appear cloudy and take on that terrifying appearance about which legends are made. But vision is not the main thing for snakes; they mainly attack moving objects. That's why the fairy tale says that the monkeys sat in a daze - they instinctively knew how to escape.

Not all snakes have unique heat sensors, but still infrared radiation and they distinguish colors. The snake has binocular vision, which means she sees two pictures. And the brain, quickly processing the information received, gives it an idea of ​​the size, distance and outline of the potential victim.

Birds

Birds are amazing in their diversity of species. It is interesting that the vision of this category of living beings also varies greatly. It all depends on what kind of life the bird leads.

So, everyone knows that predators have extremely acute vision. Some species of eagles can spot their prey from a height of more than a kilometer and drop like a stone to catch it. Did you know that certain species birds of prey are able to see ultraviolet light, which allows them to find nearby burrows in the dark

And the budgie living in your home has excellent eyesight and is able to see everything in color. Studies have proven that these individuals distinguish each other using bright plumage.

Of course, this topic is very broad, but we hope that the facts presented will be useful to you in understanding how animals see.

Do animals see colors? This interesting question, but it is not easy to give an accurate and comprehensive answer to it. It is difficult for us, who have color vision, to imagine the universe without colors, and we naturally have the assumption that all living beings also perceive the world around us in the form of multicolored pictures. However, this idea does not correspond to reality.

Color is a rather arbitrary and difficult to define concept. Color perception is not easy to research and explain; that is why scientists have long experienced difficulties in objective and accurate interpretation this ability. In essence, no object has color; it simply absorbs white daylight and reflects only one fraction of this light, one or another part of the solar spectrum. For example, green leaves of a tree absorb all parts of the spectrum except green, which is reflected by them; this is what makes them green to our eyes.

Try to explain to a blind person, without resorting to comparisons, what the color red is. This will turn out to be completely impossible. Even among sighted people they are widespread various degrees color blindness. People often evaluate the same color differently; Additionally, our color appreciation continues to improve and change. After all, Homer constantly calls the sea wine-red, and some ancient Greek authors mention the green color of the human face.

Ultimately, everything here depends on the peculiarities of the perceiving optical apparatus - a small defect or deviation from the norm is enough, for example, the absence in a person of one of the three light-sensitive “wires” leading from the retina of the eye to the brain. Each of these pathways provides the perception of one of the primary colors: red, green or blue. Most colorblind people do not have a green "wire"; others lack the red “wire” and are blind to the color red. IN physical sense changes in the human body are extremely insignificant; they come down only to features nervous system. There is every reason to believe that a number of animals that have eyes similar to humans completely lack those small details that provide color perception.

WORLD OF WHITE AND BLACK

From what has been said, it is quite clear how difficult it is (considering also that we ourselves may suffer from color blindness to some small extent) to apply our limited and not entirely accurate knowledge in the field of color perception to other creatures. A lot of research has been devoted to this topic, but many of them are insufficiently conclusive. It is extremely difficult to establish whether or not a particular animal distinguishes colors. After all, animals themselves are not able to answer this question. Moreover, it is almost always difficult to decide what the animal is reacting to - to the color or to the degree of brightness and whiteness of the object. Therefore, in order for the experiment to be valuable, it is necessary to use colors that are equivalent in brightness and degree of whiteness. Otherwise, the experimental animal, especially if it belongs to higher animals, can distinguish red from green by relative brightness, as is the case in people suffering from color blindness.

But despite the obvious limitations, we still know something in this area. Thus, we can say with confidence that almost all mammals, with the exception of all species, are completely color blind. They live in a world of black and white, with a significant range of gray shades in between. They often clearly perceive the difference in the intensity of black, in the light saturation of white and gray tones. The latter circumstance often leads people to the conclusion that certain animals (for example, dogs) distinguish between certain colors.

How often an admiring owner is ready to swear that his dog recognizes a dress by the color, even if it is worn by a stranger, that he distinguishes a bowl or a pillow solely by its color! It's hard to imagine that you can live in a world devoid of colors! Meanwhile, most mammals in their habits belong to the type of nocturnal or crepuscular animals; they emerge from their shelters only when the world begins to plunge into darkness and lose its colors, illuminated only by the weak and uncertain light of the moon.

However, all this is not so unusual for people. After all, we easily watch monochrome films; Many newspapers and magazines are still illustrated with monochromatic photographs, and we perceive them as a reflection of true life. A simple drawing made in black pencil often seems extremely natural and alive to us. Despite all of humanity’s predilection for colors, we feel their absence much less than we might sometimes think.

A TOREADOR DOESN'T NEED A RED CAPE

Along with others, the following simple experiment was carried out. Small squares of gray paper (various shades, but the same brightness) were arranged in a checkerboard pattern; There was a blue square in the center. A feeder was installed on each square, and syrup was poured into the feeder located on the blue square; the rest were empty. After some time, the bees were trained to fly only to the blue square, even if its position relative to the others changed.

When the blue paper was replaced with red paper (of the same brightness), the bees turned out to be disoriented - they could not distinguish the red square from the gray ones. Bees are not only blind to the color red; they live as if in a world of blue, purple and yellow shades; at the same time, they (like a number of other insects) are able to penetrate further than humans into the ultraviolet part of the spectrum. Of course, insects that carry pollen fly to flowers, guided not only by color, but also by smell; This is evidenced, in particular, by how easily bees find flowers of willow, ivy, and linden.

MOSQUITOES PREFER BLACK

As a rule, only insects with well-developed, compound eyes have color perception. Dragonflies have the best color perception among insects; second place appears to be occupied by wasp flies, as well as some species of moths. Common flies distinguish blue; they probably don’t like it, since they avoid windows washed with blue, blue walls and curtains. Mosquitoes, which distinguish between yellow, white and black, apparently prefer the latter. In one of the areas abounding in these insects in Oregon (USA), an experiment was conducted in which seven people participated, dressed in dresses of different colors. It was found that greatest number mosquitoes were attracted by black clothing (1499 in half a minute); in second place, with a significant lag, was white (520 insects over the same period of time).