The sharpest night vision. Which animals, fish and birds have the best vision Features of the iris
Eyes, nose, ears - in the wild, all organs serve the survival of the animal. Eyes play a vital role in the life of any living creature, but not all animals see the same. Visual acuity does not depend on the size or number of eyes.
So, even the most vigilant among many-eyed spiders, the jumping spider, sees the victim only at a distance of 8 centimeters, but in color. It should be noted that all insects have poor eyesight.
Animals that live underground, such as moles, have no vision at all. Mammals that live in water, such as beavers and otters, have poor vision.
Animals hunted by predators have panoramic vision. It is extremely difficult for a nightjar to sneak up on a bird unnoticed. Her bulging, large eyes have a wide slit that curves toward the back of her head. As a result, the viewing angle reaches three hundred and sixty degrees!
It is interesting, for example, that eagles have two eyelids, while insects do not have eyelids at all and sleep with their eyes open. The eagle's second eyelid is completely transparent; it protects the bird of prey's eye from the wind during a swift attack.
Birds of prey have the sharpest vision in the animal world. In addition, these birds can instantly shift the focus of vision from long distances to near objects. .jpg)
Birds of prey, eagles, can see their prey at a distance of 3 kilometers. Like all predators, they have binocular vision, when both eyes look at the same object, this makes it easier to calculate the distance to prey.
But the absolute champions of vigilance in the animal world are representatives of the falcon family. The world's most famous falcon, the peregrine falcon or, as it is also called, the pilgrim, can spot game from a distance of 8 kilometers. 
The peregrine falcon is not only the most vigilant, but also the fastest bird, and in general a living creature, in the world. According to experts, in a rapid diving flight it is capable of reaching speeds of over 322 km/h, or 90 m/s. For comparison: the cheetah, the fastest-footed land mammal, runs at a speed of 110 km/h; The spiny-tailed swift, living in the Far East, is capable of flying at a speed of 170 km/h. But, it should be noted that in horizontal flight the peregrine falcon is still inferior to the swift.
Peregrine Falcon(lat. Falco peregrinus) - a bird of prey from the falcon family, common on all continents except Antarctica. During a hunt, the peregrine falcon plans in the sky, having discovered prey, it rises above the victim and rapidly dives down almost at a right angle, inflicting fatal blows to the victim with its paw claws.
Cats are typical nocturnal predators. For a fruitful hunt, they need to make maximum use of all their senses. The “calling card” of all cats without exception is their unique night vision. A cat's pupil can dilate up to 14 mm, allowing a huge beam of light into the eye. This allows them to see perfectly in the dark. In addition, the cat's eye, like the Moon, reflects light: this explains the glow of cat's eyes in the dark.
All seeing dove
Pigeons have an amazing feature in the visual perception of the surrounding world. Their viewing angle is 340°. These birds see objects located at a much greater distance than humans see them. That is why, at the end of the 20th century, the US Coast Guard used pigeons in search and rescue operations. Acute pigeon vision allows these birds to perfectly distinguish objects at a distance of 3 km. Since impeccable vision is the prerogative of mainly predators, pigeons are one of the most vigilant peaceful birds on the planet.
Falcon vision is the most vigilant in the world!
The bird of prey, the falcon, is recognized as the most vigilant animal in the world. These feathered creatures can track small mammals (voles, mice, gophers) from great heights and at the same time see everything that happens on their sides and in front. According to experts, the most vigilant bird in the world is the peregrine falcon, capable of spotting a small vole from a height of up to 8 km!
Pisces are no slouch either!
Among the fish with excellent vision, the inhabitants of the deep are especially distinguished. These include sharks, moray eels, and monkfish. They are able to see in pitch darkness. This happens because the density of rods in the retina of such fish reaches 25 million/sq.mm. And this is 100 times more than in humans.
Horse vision
Horses see the world around them using peripheral vision because their eyes are located on the sides of their heads. However, this does not at all prevent horses from having a viewing angle of 350°. If a horse raises its head up, its vision will be closer to spherical.
High speed flies
It has been proven that flies have the fastest visual reaction in the world. In addition, flies see five times faster than humans: their frame rate is 300 images per minute, while humans have only 24 frames per minute. Scientists from Cambridge claim that the photoreceptors on the retina of flies' eyes can physically shrink.
Not only chameleons, but also seahorses can look in two directions at once. Animals often see much better than humans.
Even those who are considered the closest genetic relatives of humans - apes - see three times better than him. And not only them, of course. An eagle, for example, also has three times more keen vision than a human.
Deep-sea fish, as is known, can see in pitch darkness, and all because the density of rods in their retina reaches 25 million/sq.mm, which is 100 times more than in humans.
Cats also see well in the dark because their pupils can dilate up to 14 millimeters. And dogs see three times better in the dark than we do.
Dogs have an average visibility of 240-250 degrees, which is 60-70 units higher than that of humans.
The pigeon has a viewing angle of 340 degrees. A horse with its head raised also has near-spherical vision. However, as soon as the horse lowers its head, it loses half of its vision. The record holder in panoramic vision is the woodcock bird, which has almost all-round vision!
A fly's image changing speed is 300 frames per second, i.e. it exceeds the similar ability of a person by 5-6 times.
White butterflies (colias) can distinguish image elements of 30 microns, outperforming humans by more than three times.
The vulture distinguishes small rodents from a distance of up to 5 kilometers.
The Falcon is able to see a target 10 cm in size from a distance of 1.5 km, and even at high speed it retains a clear image of objects.
The cockroach notices movement of 0.0002 mm. So, when you are standing in the kitchen and trying to rush at a cockroach to kill it with a slipper, you have practically no chance.
Eyes- an organ that allows a person to live a full life, admire the beauty of the surrounding nature and exist comfortably in society. People understand how important the eyes are, but they rarely think about why they blink, why they cannot sneeze with their eyes closed, and other interesting facts related to this unique organ.
10 interesting facts about the human eye
The eyes are the conductor of information about the world around us.
In addition to vision, a person has organs of touch and smell, but it is the eyes that conduct 80% of the information that tells about what is happening around. The ability of the eyes to capture images is very important, since it is visual images that retain memory longer. When meeting a specific person or object again, the organ of vision activates memories and gives rise to thought.
Scientists compare the eyes to a camera, the quality of which is many times higher than that of ultra-modern technology. Bright and content-rich pictures allow a person to easily navigate the world around them.
The cornea of the eye is the only tissue in the body that does not receive blood.
The cornea of the eye receives oxygen directly from the air
The uniqueness of such an organ as the eyes lies in the fact that no blood flows into its cornea. The presence of capillaries would negatively affect the quality of the image captured by the eye, so oxygen, without which not a single organ of the human body can function effectively, receives oxygen directly from the air.
Highly sensitive sensors transmitting signals to the brain
The eye is a miniature computer
Ophthalmologists (vision specialists) compare the eyes to a miniature computer that captures information and instantly transmits it to the brain. Scientists have calculated that the “RAM” of the organ of vision can process about 36 thousand bits of information within an hour; programmers know how large this volume is. Meanwhile, the weight of miniature laptop computers is only 27 grams.
What does having close eyes give a person?
A person sees only what is happening directly in front of him
The location of the eyes in animals, insects and humans is different, this is explained not only by physiological processes, but also by the nature of life and the gray habitat of a living creature. The close placement of the eyes provides depth of image and three-dimensionality of objects.
Humans are more advanced creatures, therefore they have high-quality vision, especially when compared with marine life and animals. True, such an arrangement has its drawback - a person sees only what is happening directly in front of him, the view is significantly reduced. In many animals, an example is a horse, the eyes are located on the sides of the head, this structure allows you to “capture” more space and react in time to approaching danger.
Do all the inhabitants of the earth have eyes?
Approximately 95 percent of living creatures on our planet have vision
Approximately 95 percent of living creatures on our planet have an organ of vision, but most of them have a different eye structure. In the inhabitants of the deep sea, the organ of vision consists of light-sensitive cells that are not capable of distinguishing color and shape; all that such vision is capable of is perceiving light and its absence.
Some animals determine the volume and texture of objects, but at the same time see them exclusively in black and white. A characteristic feature of insects is the ability to see many pictures at the same time, but they do not recognize colors. Only human eyes have the ability to accurately convey the colors of surrounding objects.
Is it true that the human eye is the most perfect?
There is a myth that a person can only recognize seven colors, but scientists are ready to debunk it. According to experts, the human visual organ is capable of perceiving over 10 million colors; no living creature has such a feature. However, there are other criteria that are not characteristic of the human eye, for example, some insects are able to recognize infrared rays and ultraviolet signals, and the eyes of flies have the ability to detect movement very quickly. The human eye can only be called the most perfect in the field of color recognition.
Who on the planet has the most island eyesight?
Veronica Seider - the girl with the sharpest eyesight on the planet
The name of a student from Germany, Veronica Seider, is listed in the Guinness Book of Records; the girl has the sharpest eyesight on the planet. Veronica recognizes a person's face at a distance of 1 kilometer 600 meters, this figure is approximately 20 times higher than the norm.
Why does a person blink?
If a person did not blink, his eyeball would quickly dry out and quality vision would be out of the question. Blinking causes the eye to become covered with tear fluid. It takes about 12 minutes per day for a person to blink – once every 10 seconds, during which time the eyelids close over 27 thousand times.
A person begins to blink for the first time at six months.
Why do people start sneezing in bright light?
The human eyes and nasal cavity are connected by nerve endings, so often when exposed to bright light we begin to sneeze. By the way, no one can sneeze with their eyes open; this phenomenon is also associated with the reaction of nerve endings to external stimuli of calm.
Restoring vision with the help of sea creatures
Scientists have found similarities in the structure of the human eye and sea creatures, in this case we are talking about sharks. Modern medicine methods make it possible to restore human vision by transplanting a shark cornea. Similar operations are very successfully practiced in China.
Sincerely,
If you say it's from a cat, you'd be wrong.
Humans can see well in the dark, but nocturnal animals like cats give us a hundred points ahead. But who has the most sensitive eyes?
The human eye is one of the most amazing achievements of evolution. He is able to see small specks of dust and huge mountains, near and far, in full color. Working in tandem with a powerful processor in the form of the brain, the eyes allow a person to distinguish movement and recognize people by their faces.
One of the most impressive features of our eyes is so well developed that we don't even notice it. When we enter a dimly lit room from bright light, the level of illumination in the surrounding environment drops sharply, but the eyes adapt to this almost instantly. As a result of evolution, we have adapted to see in poor light.
But on our planet there are living beings who see in the dark much better than humans. Try reading a newspaper in the deep twilight: the black letters merge with the white background into a blurry gray spot in which you can’t understand anything. But a cat in a similar situation would not experience any problems - of course, if she could read.
But even cats, despite their habit of hunting at night, see in the dark no better than anyone else. Creatures with the sharpest night vision have evolved unique visual organs that allow them to capture literally grains of light. Some of these creatures are able to see in conditions where, from the point of view of our understanding of physics, nothing can be seen in principle.
To compare night vision acuity, we will use lux, a unit that measures the amount of light per square meter. The human eye works well in bright sunlight, where illumination can exceed 10 thousand lux. But we can see at just one lux—that’s about how much light there is on a dark night.
Domestic cat ( Felis catus): 0.125 lux
Photo from www.listofimages.com
To see, cats need eight times less light than humans. Their eyes are generally similar to ours, but they have several features that allow them to work well in the dark.
Cat eyes, like human eyes, are made up of three main components: the pupil, the hole through which light enters; lens - focusing lens; and the retina, the sensitive screen onto which the image is projected.
In humans, the pupils are round, but in cats they have the shape of an elongated vertical ellipse. During the day they narrow into slits, and at night they open to their maximum width. The human pupil can also change size, but not within such a wide range.
Cats' lenses are larger than those of humans and are able to collect more light. And behind the retina they have a reflective layer called the tapetum lucidum, also known simply as the “mirror.” Thanks to it, cats' eyes glow in the dark: light passes through the retina and is reflected back. This way, light hits the retina twice, giving the receptors an extra chance to absorb it.
The composition of the retina itself in cats is also different from ours. There are two types of light-sensitive cells: cones, which detect colors but only work in good light; and rods - which do not perceive color, but work in the dark. Humans have many cones, which give us rich, full-color vision, but cats have many more rods: 25 per cone (in humans, this ratio is one to four).
Cats have 350 thousand rods per square millimeter of retina, while humans have only 80-150 thousand. In addition, each neuron leaving the cat's retina transmits signals from about one and a half thousand rods. The weak signal is thus amplified and transformed into a detailed image.
There is a downside to such acute night vision: during the daytime, cats see about the same as people with red-green color blindness. They can distinguish blue from other colors, but cannot tell the difference between red, brown and green.
Tarsier ( Tarsiidae): 0.001 lux
Photo from www.bohol.ph
Tarsiers are tree-dwelling primates found in Southeast Asia. Relative to the rest of their body proportions, they appear to have the largest eyes of any mammal. The body of the tarsier, excluding the tail, usually reaches a length of 9-16 centimeters. The eyes have a diameter of 1.5-1.8 centimeters and occupy almost the entire intracranial space.
Tarsiers feed mainly on insects. They hunt early in the morning and late in the evening, under illumination of 0.001-0.01 lux. Moving along the treetops, they must look out for small, well-camouflaged prey in almost complete darkness and at the same time not fall, jumping from branch to branch.
They are helped in this by their eyes, which are generally similar to human eyes. The giant tarsier's eye lets in a lot of light, and the amount of light is regulated by the strong muscles surrounding the pupil. The large lens focuses the image on the retina, strewn with rods: the tarsier has more than 300 thousand of them per square millimeter, like a cat.
These large eyes have a disadvantage: tarsiers are unable to move them. As compensation, nature endowed them with necks that rotate 180 degrees.
Dung-beetle ( Onitis sp.): 0.001-0.0001 lux
Photo from www.bbc.co.uk
Where there is dung, there are usually dung beetles. They choose the freshest pile of manure and begin to live in it, rolling balls of manure as a reserve or digging tunnels under the pile to make a storage room for themselves. Dung beetles of the genus Onitis fly out in search of dung at different times of the day.
Their eyes are very different from human eyes. The eyes of insects are faceted, they consist of many structural elements - ommatidia.
In beetles that fly during the day, ommatidia are enclosed in pigment shells that absorb excess light so that the sun does not blind the insect. The same membrane separates each ommatidium from its neighbors. However, in the eyes of beetles that are nocturnal, these pigment membranes are absent. Therefore, light collected by many ommatidia can be transmitted to just one receptor, which significantly increases its photosensitivity.
Genus Onitis combines several different species of dung beetles. The eyes of diurnal species have insulating pigment membranes, the eyes of evening beetles sum up signals from ommatidia, and nocturnal species sum up signals from a number of receptors twice as large as those of evening beetles. Eyes of a nocturnal species Onitis aygulus, for example, 85 times more sensitive than daylight eyes Onitis belial.
Halictid bees ( Megalopta genalis): 0.00063 lux
Photo from www.bbc.co.uk
But the rule described above does not always apply. Some insects can see in very low light, despite the fact that their visual organs are clearly adapted for daylight.
Eric Warrent and Elmut Kelber from Lund University in Sweden found that some bees have pigment membranes in their eyes that insulate the ommatidia from each other, but they are nevertheless perfectly able to fly and search for food in the dark at night. For example, in 2004, two scientists demonstrated that halictid bees are able to navigate under illumination 20 times less intense than starlight.
But the eyes of the halictid bee are designed to see well in daylight, and during the course of evolution, bees had to adapt their visual organs somewhat. After the retina has absorbed light, this information is transmitted to the brain through nerves. At this stage, the signals can be summed to increase the brightness of the image.
These bees have special neurons that connect ommatidia into groups. In this way, signals coming from all the ommatidia in the group are fused together before being sent to the brain. The image is less sharp, but significantly brighter.
Carpenter Bee ( Xylocopa tranquebarica): 0.000063 lux
Photo from www.bbc.co.uk
Carpenter bees, found in the mountains called the Western Ghats in southern India, see even better in the dark. They can fly even on moonless nights. “They can fly in starlight, cloudy nights and strong winds,” says Hema Somanathan from the Indian Institute of Science Education and Research in Thiruvananthapuram.
Somanathan discovered that carpenter bee ommatidia have unusually large lenses, and the eyes themselves are quite large in proportion to other parts of the body. All this helps to capture more light.
However, this is not enough to explain such excellent night vision. Perhaps carpenter bees also have ommatidia in groups, like their counterparts Megalopta genalis.
Carpenter bees don't just fly at night. “I have seen them fly around during the day when their nests are being destroyed by predators,” says Somanathan. “If you blind them with a flash of light, they simply fall, their vision is not able to process a large amount of light. But then they come to their senses and take off again.”
Of all fauna, carpenter bees seem to have the most acute night vision. But in 2014, another contender for the championship title appeared.
American cockroach ( Periplaneta americana): less than one photon per second
On the screensaver there is a photo from the website www.activepestsolutionsltd.co.uk
It is not possible to directly compare cockroaches with other living creatures because their visual acuity is measured differently. However, their eyes are known to be unusually sensitive.
In a series of experiments reported in 2014, Matti Väckström of the University of Oulu in Finland and his colleagues examined how individual light-sensitive cells in cockroach ommatidia responded to very low light levels. They inserted the thinnest electrodes made of glass into these cells.
Light consists of photons—massless elementary particles. The human eye needs at least 100 photons to hit it to sense anything. However, the receptors in the cockroach's eyes responded to movement even if each cell received only one photon of light every 10 seconds.
A cockroach has 16-28 thousand green-sensitive receptors in each eye. According to Weckström, in dark conditions, signals from hundreds or even thousands of these cells are summed up (recall that in a cat up to 1500 optic rods can work together). The effect of this summation, according to Weckström, is “enormous,” and it seems that it has no analogues in living nature.
“Cockroaches are impressive. Less photon per second! says Kelber. “This is the sharpest night vision.”
But bees can outdo them in at least one respect: American cockroaches don't fly in the dark. “Control of flight is much more difficult - the insect moves quickly, and collision with obstacles is dangerous,” comments Kelber. “In this sense, carpenter bees are the most amazing. They are able to fly and forage on moonless nights and still see colors.”