What compensates for the poor development of vision and hearing in snakes. How do snakes see us? How does a snake see a person?

Introduction ................................................ ................................................. ............3

1. There are many ways to see - it all depends on the goals .......................................... ..4

2. Reptiles. General Information................................................... .............................8

3. Organs infrared vision serpent................................................. ............12

4. "Heat-seeing" snakes .............................................. ................................................17

5. Snakes strike prey blindly .............................................. .......................20

Conclusion................................................. ................................................. .......22

Bibliography................................................ ...............................................24

Introduction

Are you sure that the world looks exactly the way it appears to our eyes? But animals see it differently.

The cornea and lens in humans and higher animals are arranged in the same way. Similar is the device of the retina. It contains light-sensitive cones and rods. Cones are responsible for color vision, rods are responsible for vision in the dark.

The eye is an amazing organ human body, live optical device. Thanks to him, we see day and night, we distinguish colors and the volume of the image. The eye is built like a camera. Its cornea and lens, like a lens, refract and focus light. The retina lining the fundus acts as a sensitive film. It consists of special light-receiving elements - cones and rods.

And how are the eyes of our "smaller brothers" arranged? Animals that hunt at night have more rods in their retinas. Those representatives of the fauna who prefer to sleep at night have only cones in the retina. The most vigilant in nature are diurnal animals and birds. This is understandable: without sharp vision, they simply will not survive. But nocturnal animals also have their advantages: even with minimal lighting, they notice the slightest, almost imperceptible movements.

In general, humans see clearer and better than most animals. The fact is that in the human eye there is a so-called yellow spot. It is located in the center of the retina on the optical axis of the eye and contains only cones. Rays of light fall on them, which are least of all distorted, passing through the cornea and lens.

The “yellow spot” is a specific feature of the human visual apparatus, all other types are deprived of it. It is because of the absence of this important adaptation that dogs and cats see worse than us.

1. There are many ways to see - it all depends on the goals.

Each species has developed its own visual abilities as a result of evolution. as much as it is required for its habitat and way of life. If we understand this, we can say that all living organisms have “ideal” vision in their own way.

A person sees poorly under water, but the eyes of a fish are arranged in such a way that, without changing position, it distinguishes objects that for us remain "overboard" of vision. Bottom-dwelling fish such as flounder and catfish have their eyes positioned at the top of their heads to see enemies and prey that usually come from above. By the way, the eyes of the fish can turn in different directions independently of each other. More vigilantly than others, predatory fish see under water, as well as inhabitants of the depths, feeding on the smallest creatures - plankton and bottom organisms.

The vision of animals is adapted to the familiar environment. Moles, for example, are short-sighted - they see only up close. But another vision in the complete darkness of their underground burrows is not needed. Flies and other insects do not distinguish the outlines of objects well, but in one second they are able to fix a large number of individual “pictures”. About 200 compared to 18 in humans! Therefore, the fleeting movement, which we perceive as barely perceptible, for the fly is “decomposed” into many single images - like frames on a film. Thanks to this property, insects instantly find their bearings when they need to catch their prey on the fly or escape from enemies (including people with a newspaper in their hand).

Insect eyes are one of nature's most amazing creations. They are well developed and occupy most of the surface of the insect's head. They consist of two types - simple and complex. There are usually three simple eyes, and they are located on the forehead in the form of a triangle. They distinguish between light and darkness, and when an insect flies, they follow the horizon line.

Compound eyes consist of many small eyes (facets) that look like convex hexagons. Each such eye is equipped with a kind of simple lens. Compound eyes give a mosaic image - each facet "fits" only a fragment of the object that has fallen into the field of view.

Interestingly, in many insects, individual facets are enlarged in compound eyes. And their location depends on the lifestyle of the insect. If he is more “interested” in what is happening above him, the largest facets are in the upper part of the compound eye, and if below it, in the lower. Scientists have repeatedly tried to understand what exactly insects see. Does the world really appear before their eyes in the form of a magical mosaic? There is no single answer to this question yet.

Especially many experiments were carried out with bees. During the experiments, it turned out that these insects need vision for orientation in space, recognizing enemies and communicating with other bees. In the dark, the bees do not see (and do not fly). But they distinguish some colors very well: yellow, blue, bluish-green, purple and also a specific “bee”. The latter is the result of "mixing" ultraviolet, blue and yellow. In general, the sharpness of their vision of bees may well compete with humans.

Well, how do creatures who have very poor eyesight or those who are completely deprived of it manage? How do they navigate in space? Some also "see" - just not with their eyes. The simplest invertebrates and jellyfish, which are 99 percent water, have light-sensitive cells that perfectly replace their usual visual organs.

The vision of the representatives of the fauna inhabiting our planet still holds many amazing secrets, and they are waiting for their researchers. But one thing is clear: all the diversity of eyes in wildlife is the result of a long evolution of each species and is closely related to its lifestyle and habitat.

People

We clearly see objects up close and distinguish the subtlest shades of colors. In the center of the retina are the cones "yellow spot", which are responsible for visual acuity and color perception. Overview - 115-200 degrees.

On the retina of our eye, the image is fixed upside down. But our brain corrects the picture and transforms it into the “correct” one.

cats

Wide-set cat eyes give a 240-degree field of view. The retina of the eye is mainly equipped with rods, cones are collected in the center of the retina (area of acute vision). Night vision is better than daytime. In the dark, a cat sees 10 times better than us. Her pupils dilate, and the reflective layer beneath the retina sharpens her vision. And the cat distinguishes colors poorly - only a few shades.

Dogs

For a long time it was believed that the dog sees the world in black and white. However, dogs can still distinguish colors. It's just that this information is not too meaningful for them.

Vision in dogs is 20-40% worse than in humans. An object that we distinguish at a distance of 20 meters "disappears" for a dog if it is more than 5 meters away. But night vision is excellent - three to four times better than ours. The dog is a night hunter: he sees far in the darkness. In the dark, a guard dog breed is able to see a moving object at a distance of 800-900 meters. Overview - 250-270 degrees.

Birds

Feathers are champions in visual acuity. They distinguish colors well. Most birds of prey visual acuity is several times higher than that of a human. Hawks and eagles notice moving prey from a height of two kilometers. Not a single detail escapes the attention of a hawk soaring at a height of 200 meters. His eyes "magnify" the central part of the image by 2.5 times. The human eye does not have such a “magnifier”: the higher we are, the worse we see what is below.

snakes

The snake has no eyelids. Its eye is covered with a transparent shell, which is replaced by a new one during molting. The snake's gaze focuses by changing the shape of the lens.

Most snakes can distinguish colors, but the outlines of the image are blurred. The snake mainly reacts to a moving object, and even then, if it is nearby. As soon as the victim moves, the reptile discovers it. If you freeze, the snake will not see you. But he can attack. The receptors located near the eyes of the snake capture the heat emanating from a living creature.

Fish

The eye of a fish has a spherical lens that does not change shape. To focus the eye, the fish brings the lens closer or further away from the retina with the help of special muscles.

In clear water, the fish sees an average of 10-12 meters, and clearly - at a distance of 1.5 meters. But the angle of view is unusually large. Fish fix objects in the zone of 150 degrees vertically and 170 degrees horizontally. They distinguish colors and perceive infrared radiation.

bees

"Bees of daytime vision": what to look at at night in the hive?

The bee's eye detects ultraviolet radiation. She sees another bee in lilac color and as if through the optics that “compressed” the image.

The eye of a bee consists of 3 simple and 2 compound compound eyes. Difficult during the flight distinguish between moving objects and the outlines of stationary ones. Simple - determine the degree of light intensity. Bees have no night vision”: what to look at at night in a hive?

2. Reptiles. General information

Reptiles have a bad reputation and few friends among humans. There are many misunderstandings related to their body and lifestyle that have survived to this day. Indeed, the very word "reptile" means "animal that crawls" and seems to recall the widespread idea of them, especially snakes, as disgusting creatures. Despite the prevailing stereotype, not all snakes are venomous and many reptiles play a significant role in regulating the number of insects and rodents.

Most reptiles are predators with a well-developed sensory system that helps them find prey and avoid danger. They have excellent eyesight, and snakes, in addition, have a specific ability to focus their eyes by changing the shape of the lens. Nocturnal reptiles, like geckos, see everything in black and white, but most others have good color vision.

Hearing is of little importance to most reptiles, and the internal structures of the ear are usually poorly developed. Most also lack an outer ear, except for the tympanic membrane, or "tympanum," which receives vibrations transmitted through the air; from the eardrum they are transmitted through the bones of the inner ear to the brain. Snakes do not have an external ear and can perceive only those vibrations that are transmitted along the ground.

Reptiles are characterized as cold-blooded animals, but this is not entirely accurate. Their body temperature is mainly determined by the environment, but in many cases they can regulate it and, if necessary, maintain it for more high level. Some species are able to generate and retain heat within their own body tissues. Cold blood has some advantages over warm blood. Mammals need to maintain their body temperature at a constant level within very narrow limits. To do this, they constantly need food. Reptiles, on the contrary, tolerate a decrease in body temperature very well; their life interval is much wider than that of birds and mammals. Therefore, they are able to populate places that are not suitable for mammals, for example, deserts.

Once having eaten, they can digest food at rest. In some of the largest species, several months may pass between meals. Large mammals would not survive on this diet.

Apparently, among reptiles, only lizards have well-developed eyesight, since many of them hunt fast-moving prey. Aquatic reptiles rely more on the senses of smell and hearing to track prey, find a mate, or detect an approaching enemy. Their vision plays a secondary role and acts only at close range, visual images are vague, and there is no ability to focus on stationary objects for a long time. Most snakes have rather weak eyesight, usually only able to detect moving objects that are nearby. The numbing response in frogs when approached by, for example, a snake, is a good defense mechanism, since the snake will not be aware of the presence of the frog until it does sudden movement. If this happens, then visual reflexes will allow the snake to quickly deal with it. Only tree snakes, which coil around branches and grab birds and insects in flight, have good binocular vision.

Snakes have a different sensory system than other hearing reptiles. Apparently, they do not hear at all, so the sounds of the snake charmer's pipe are inaccessible to them, they enter a state of trance from the movements of this pipe from side to side. They do not have an outer ear or eardrum, but they may be able to pick up some very low frequency vibrations using their lungs as sense organs. Basically, snakes detect prey or an approaching predator by vibrations in the ground or other surface they are on. The body of the snake, which is entirely in contact with the ground, acts as one large vibration detector.

Some species of snakes, including rattlesnakes and pit vipers, detect prey by infrared radiation from its body. Under the eyes they have sensitive cells that detect the slightest temperature changes down to fractions of a degree and, thus, orient the snakes to the location of the victim. Some boas also have sensory organs (on the lips along the mouth opening) that can detect changes in temperature, but they are less sensitive than those of rattlesnakes and pit vipers.

For snakes, the senses of taste and smell are very important. The quivering, forked tongue of a snake, which some people think of as a "snake's sting," actually collects traces of various substances quickly disappearing into the air and carries them to sensitive depressions on the inside of the mouth. There is a special device (Jacobson's organ) in the sky, which is connected to the brain by a branch of the olfactory nerve. The constant releasing and retracting of the tongue is effective method air sampling for important chemical components. When retracted, the tongue is close to Jacobson's organ, and its nerve endings detect these substances. In other reptiles, the sense of smell plays a large role, and the part of the brain that is responsible for this function is very well developed. The organs of taste are usually less developed. Like snakes, Jacobson's organ is used to detect particles in the air (in some species using the tongue) that carry the sense of smell.

Many reptiles live in very dry places, so keeping water in their bodies is very important to them. Lizards and snakes are the best conservers of water, but not because of their scaly skin. Through the skin, they lose almost as much moisture as birds and mammals.

While in mammals a high respiratory rate leads to a large evaporation from the surface of the lungs, in reptiles the respiratory rate is much lower and, accordingly, water loss through the lung tissue is minimal. Many species of reptiles are equipped with glands capable of purifying the blood and body tissues of salts, excreting them in the form of crystals, thereby reducing the need to pass large volumes of urine. Other unwanted salts in the blood are converted into uric acid, which can be eliminated from the body with minimal water.

Reptile eggs contain everything necessary for a developing embryo. This is a supply of food in the form of a large yolk, water contained in the protein, and a multilayer protective shell that does not let in dangerous bacteria, but allows air to breathe.

The inner shell (amnion), immediately surrounding the embryo, is similar to the same shell in birds and mammals. The allantois is a more powerful membrane that acts as a lung and excretory organ. It provides the penetration of oxygen and the release of waste substances. Chorion - the shell that surrounds the entire contents of the egg. The outer shells of lizards and snakes are leathery, but those of turtles and crocodiles are harder and more calcified, like eggshells in birds.

4. Organs of infrared vision of snakes

Infrared vision in snakes requires non-local imaging

The organs that allow snakes to "see" thermal radiation give an extremely blurry image. Nevertheless, a clear thermal picture of the surrounding world is formed in the snake's brain. German researchers have figured out how this can be.

Some species of snakes have a unique ability to capture thermal radiation, which allows them to look at the surrounding world in absolute darkness. True, they “see” thermal radiation not with their eyes, but with special heat-sensitive organs.

The structure of such an organ is very simple. Near each eye is a hole about a millimeter in diameter, which leads into a small cavity of about the same size. On the walls of the cavity there is a membrane containing a matrix of thermoreceptor cells approximately 40 by 40 cells in size. Unlike rods and cones in the retina, these cells do not respond to the "brightness of light" of heat rays, but to the local temperature of the membrane.

This organ works like a camera obscura, a prototype of cameras. A small warm-blooded animal against a cold background emits "heat rays" in all directions - far infrared radiation with a wavelength of about 10 microns. Passing through the hole, these rays locally heat the membrane and create a "thermal image". Due to the highest sensitivity of receptor cells (a temperature difference of thousandths of a degree Celsius is detected!) and good angular resolution, a snake can notice a mouse in absolute darkness from a fairly large distance.

From the point of view of physics, just a good angular resolution is a mystery. Nature has optimized this organ so that it is better to "see" even weak heat sources, that is, it simply increased the size of the inlet - the aperture. But the larger the aperture, the more blurry the image turns out (we are talking, we emphasize, about the most ordinary hole, without any lenses). In the situation with snakes, where the aperture and depth of the camera are approximately equal, the image is so blurred that nothing but “there is a warm-blooded animal somewhere nearby” can be extracted from it. However, experiments with snakes show that they can determine the direction of a point source of heat with an accuracy of about 5 degrees! How do snakes manage to achieve such a high spatial resolution with such a terrible quality of "infrared optics"?

A recent article by German physicists A. B. Sichert, P. Friedel, J. Leo van Hemmen, Physical Review Letters, 97, 068105 (9 August 2006) was devoted to the study of this particular issue.

Since the real “thermal image”, the authors say, is very blurry, and the “spatial picture” that appears in the animal’s brain is quite clear, it means that there is some intermediate neuroapparatus on the way from the receptors to the brain, which, as it were, adjusts the sharpness of the image. This apparatus should not be too complicated, otherwise the snake would "think" over each image received for a very long time and would react to stimuli with a delay. Moreover, according to the authors, this device is unlikely to use multi-stage iterative mappings, but rather is some kind of fast one-step converter that works on forever hardwired in nervous system program.

In their work, the researchers proved that such a procedure is possible and quite real. They conducted mathematical modeling of how a "thermal image" appears, and developed an optimal algorithm for repeatedly improving its clarity, dubbing it a "virtual lens".

Despite the big name, the approach they used, of course, is not something fundamentally new, but just a kind of deconvolution - the restoration of an image spoiled by the imperfection of the detector. This is the reverse of motion blur and is widely used in computer image processing.

In the analysis carried out, however, important nuance: the law of deconvolution did not need to be guessed, it could be calculated from the geometry of the sensitive cavity. In other words, it was known in advance what kind of image a point source of light would give in any direction. Thanks to this, a completely blurred image could be restored with very good accuracy (ordinary graphic editors with a standard deconvolution law would not have coped with this task even close). The authors also proposed a specific neurophysiological implementation of this transformation.

Whether this work said some new word in the theory of image processing is a moot point. However, it certainly led to unexpected findings regarding the neurophysiology of "infrared vision" in snakes. Indeed, the local mechanism of "normal" vision (each visual neuron picks up information from its own small area on the retina) seems so natural that it is difficult to imagine anything much different. But if snakes really use the described deconvolution procedure, then each neuron that contributes to the whole picture of the surrounding world in the brain receives data not from a point at all, but from a whole ring of receptors passing through the entire membrane. One can only wonder how nature has managed to construct such a "non-local vision" that compensates for the defects of infrared optics with non-trivial mathematical transformations of the signal.

Infrared detectors are, of course, difficult to distinguish from the thermoreceptors discussed above. The Triatoma thermal bed bug detector could also be considered in this section. However, some thermoreceptors have become so specialized in detecting distant heat sources and determining the direction to them that it is worth considering them separately. The most famous of them are the facial and labial fossae of some snakes. The first indications that the pseudo-legged snake family Boidae (boas, pythons, etc.) and the pit viper subfamily Crotalinae (rattlesnakes, including the true rattlesnakes Crotalus and the bushmaster (or surukuku) Lachesis) have infrared sensors, were obtained from the analysis of their behavior when searching for victims and determining the direction of attack. Infrared detection is also used for defense or flight, which is caused by the appearance of a heat-radiating predator. Subsequently, electrophysiological studies of the trigeminal nerve, which innervates the labial fossae of pseudo-legged snakes and the facial fossae of pit vipers (between the eyes and nostrils), confirmed that these depressions do indeed contain infrared receptors. Infrared radiation is an adequate stimulus for these receptors, although a response can also be generated by washing the fossa with warm water.

Histological studies have shown that the pits do not contain specialized receptor cells, but unmyelinated trigeminal nerve endings, forming a wide non-overlapping branching.

In the pits of both pseudo-legged and pit-headed snakes, the surface of the bottom of the fossa reacts to infrared radiation, and the reaction depends on the location of the radiation source in relation to the edge of the fossa.

Activation of receptors in both prolegs and pit vipers requires a change in the flux of infrared radiation. This can be achieved either as a result of the movement of a heat-radiating object in the "field of view" of a relatively colder environment, or by scanning the movement of the snake's head.

The sensitivity is sufficient to detect the flow of radiation from a human hand moving into the "field of view" at a distance of 40 - 50 cm, which implies that the threshold stimulus is less than 8 x 10-5 W/cm2. Based on this, the temperature increase detected by the receptors is on the order of 0.005°C (i.e., about an order of magnitude better than the human ability to detect temperature changes).

5. "Heat-seeing" snakes

Experiments conducted in the 30s of the XX century by scientists with rattlesnakes and related pit vipers (crotalids) showed that snakes can actually see the heat emitted by the flame. Reptiles were able to detect at a great distance the subtle heat emitted by heated objects, or, in other words, they were able to feel infrared radiation, the long waves of which are invisible to humans. The ability of pit vipers to feel heat is so great that they can detect the heat emitted by a rat at a considerable distance. Heat sensors are located in snakes in small pits on the muzzle, hence their name - pitheads. Each small, forward-facing fossa, located between the eyes and nostrils, has a tiny hole, like a pinprick. At the bottom of these holes there is a membrane similar in structure to the retina of the eye, containing the smallest thermoreceptors in the amount of 500-1500 per square millimeter. Thermoreceptors of 7000 nerve endings are connected to the branch of the trigeminal nerve located on the head and muzzle. Since the zones of sensitivity of both pits overlap, the pit viper can perceive heat stereoscopically. The stereoscopic perception of heat allows the snake, by detecting infrared waves, not only to find prey, but also to estimate the distance to it. Fantastic thermal sensitivity in pit vipers is combined with a fast reaction time, allowing snakes to respond instantly, in less than 35 milliseconds, to a thermal signal. Not surprisingly, snakes with such a reaction are very dangerous.

The ability to capture infrared radiation gives the pit vipers significant capabilities. They can hunt at night and follow their main prey - rodents in their underground burrows. Although these snakes have a highly developed sense of smell, which they also use to search for prey, their deadly rush is directed by heat-sensing pits and additional thermoreceptors located inside the mouth.

Although the infrared sense of other groups of snakes is less well understood, boas and pythons are also known to have heat-sensing organs. Instead of pits, these snakes have more than 13 pairs of thermoreceptors located around the lips.

Darkness reigns in the depths of the ocean. The light of the sun does not reach there, and there flickers only the light emitted by the deep-sea inhabitants of the sea. Like fireflies on land, these creatures are equipped with organs that generate light.

The black malakost (Malacosteus niger), which has a huge mouth, lives in complete darkness at depths from 915 to 1830 m and is a predator. How can he hunt in complete darkness?

Malacoste is able to see the so-called far red light. Light waves in the red part of the so-called visible spectrum have the longest wavelength, about 0.73-0.8 micrometers. Although this light is invisible to the human eye, it is visible to some fish, including the black malakost.

On the sides of the Malacoste's eyes are a pair of bioluminescent organs that emit a blue-green light. Most of the other bioluminescent creatures in this realm of darkness also emit bluish light and have eyes that are sensitive to blue wavelengths in the visible spectrum.

The second pair of bioluminescent organs of the black malakost is located below its eyes and gives off a distant red light that is invisible to others living in the depths of the ocean. These organs give the Black Malacoste an advantage over rivals, as the light it emits helps it see its prey and allows it to communicate with other members of its species without betraying its presence.

But how does the black malacost see the far red light? According to the saying "You are what you eat," he actually gets this opportunity by eating tiny copepods, which in turn feed on bacteria that absorb far red light. In 1998, a group of scientists from the UK, which included Dr. Julian Partridge and Dr. Ron Douglas, discovered that the retina of the black malakost contained a modified version of bacterial chlorophyll, a photopigment capable of capturing far red light rays.

Thanks to far red light, some fish can see in water that would appear black to us. A bloodthirsty piranha in the murky waters of the Amazon, for example, perceives the water as a dark red, a color more penetrating than black. The water looks red because of the particles of red vegetation that absorb visible light. Only beams of far red light pass through muddy water and can be seen by the piranha. Infrared rays allow her to see prey, even if she hunts in complete darkness. Just like piranhas, carp in their natural habitats fresh water often muddy, overcrowded with vegetation. And they adapt to this by having the ability to see far red light. Indeed, their visual range (level) exceeds that of piranhas, since they can see not only in the far red, but also in true infrared light. So your favorite pet goldfish can see a lot more than you think, including the "invisible" infrared rays emitted by common household electronic devices such as TV remotes and burglar alarm beams.

5. Snakes strike prey blindly

It is known that many species of snakes, even when deprived of their sight, are able to strike their victims with supernatural accuracy.

The rudimentary nature of their thermal sensors does not suggest that the ability to perceive the thermal radiation of victims alone can explain these amazing abilities. A study by scientists from the Technical University of Munich shows that it is likely that snakes have a unique "technology" for processing visual information, reports Newscientist.

Many snakes have sensitive infrared detectors that help them navigate in space. In laboratory conditions, snakes were glued with a plaster over their eyes, and it turned out that they were able to hit a rat with an instant blow of poisonous teeth in the victim's neck or behind the ears. Such accuracy cannot be explained only by the ability of the snake to see the heat spot. Obviously, it's all about the ability of snakes to somehow process the infrared image and "clean" it from interference.

The scientists developed a model that takes into account and filters out both thermal "noise" from moving prey and any errors associated with the functioning of the detector membrane itself. In the model, a signal from each of the 2,000 thermal receptors causes the excitation of its own neuron, but the intensity of this excitation depends on the input to each of the other nerve cells. By integrating the signals from the interacting receptors into the models, the scientists were able to obtain very clear thermal images even with a high level of extraneous noise. But even relatively small errors associated with the operation of the detector membranes can completely destroy the image. To minimize such errors, the membrane thickness should not exceed 15 micrometers. And it turned out that the membranes of pit vipers have exactly this thickness, cnews.ru says.

Thus, scientists were able to prove the amazing ability of snakes to process even images that are very far from perfect. Now it is up to the validation of the model by studies of real snakes.

Conclusion

It is known that many species of snakes (in particular from the group of pitheads), even being deprived of sight, are able to hit their victims with supernatural "accuracy". The rudimentary nature of their thermal sensors does not suggest that the ability to perceive the thermal radiation of victims alone can explain these amazing abilities. A study by scientists from the Technical University of Munich suggests that it may be because snakes have a unique "technology" for processing visual information, reports Newscientist.

Many snakes are known to have sensitive infrared detectors that help them navigate and locate prey. In laboratory conditions, snakes were temporarily blinded by plastering their eyes, and it turned out that they were able to hit a rat with an instant blow of poisonous teeth aimed at the neck of the victim, behind the ears - where the rat is not able to fight back with its sharp incisors. Such accuracy cannot be explained only by the snake's ability to see a blurry heat spot.

On the sides of the front of the head, pit vipers have depressions (which gave the name to this group) in which heat-sensitive membranes are located. How is the thermal membrane "focused"? It was assumed that this body works on the principle of a camera obscura. However, the diameter of the holes is too large to implement this principle, and as a result, only a very blurry image can be obtained, which is not capable of providing the unique accuracy of a snake throw. Obviously, it's all about the ability of snakes to somehow process the infrared image and "clean" it from interference.

Thus, scientists were able to prove the amazing ability of snakes to process even images that are very far from perfect. It remains only to confirm the model with studies of real, not "virtual" snakes.

Bibliography

1. Anfimova M.I. Snakes in nature. - M, 2005. - 355 p.

2. Vasiliev K.Yu. Reptile vision. - M, 2007. - 190 p.

3. Yatskov P.P. Snake breed. - St. Petersburg, 2006. - 166 p.

We are limited by our own ideas. The perception of reality occurs due to the function of various organs, and only a few people understand that this is a rather limited vision. Maybe we are seeing a very dim version of the true reality, due to the fact that the senses are imperfect. In fact, we cannot see the world through the eyes of other life forms. But thanks to science, we can get closer to it. By studying, one can reveal how the eyes of other animals are built and how they function. For example, comparing with our vision, revealing the number of cones and rods or the shape of their eyes or pupils. And this, at least somehow, will bring us closer to that world that we have not identified.

How birds see

Birds have four types of cones, or so-called light-sensitive receptors, while humans have only three. And the area of vision reaches up to 360%, when compared with a person, then it is equal to 168%. This allows birds to visualize the world from a completely different point of view and much richer than the perception of human vision. Most birds can also see in the ultraviolet spectrum. The need for such vision arises when they get their own food. The berries and other fruits have a waxy coating that reflects ultraviolet light, making them stand out against the green foliage. Some insects also reflect ultraviolet light, giving birds an undeniable advantage.

On the left - this is how a bird sees our world, on the right - a man.

How do insects see

Insects have a complex structure of the eye, consisting of thousands of lenses that form a surface similar to a soccer ball; in which each lens is one "pixel". Like us, insects have three light-sensitive receptors. The perception of color in all insects is different. For example, some of them, butterflies and bees, can see in the ultraviolet spectrum, where the wavelength of light varies between 700 hm and 1 mm. The ability to see ultraviolet color allows the bees to see the pattern on the petals, which directs them towards the pollen. Red is the only color that is not perceived as a color by bees. Therefore, pure red flowers are rarely found in nature. Another amazing fact- the bee cannot close its eyes, and therefore sleeps with its eyes open.

On the left - this is how a bee sees our world, on the right - a person. Did you know? Praying mantises and dragonflies have the most a large number of lenses and this figure reaches 30,000.

How dogs see

Relying on outdated data, many still believe that dogs see the world in black and white, but this is an erroneous opinion. More recently, scientists have discovered that dogs have color vision, just like humans, but it's different. There are fewer cones in the retina than in the human eye. They are responsible for color perception. A feature of vision is the absence of red cones, so they cannot distinguish shades between yellow-green and orange-red colors. This is similar to color blindness in humans. Due more rods, dogs can see in the dark five times better than we can. Another feature of vision is the ability to determine the distance, which helps them a lot in hunting. But at close range, they see blurry, they need a distance of 40 cm in order to see the object.

Comparison between how a dog and a person see.

How do cats see

Cats cannot focus on small details, so they see the world a little blurry. It is much easier for them to perceive an object in motion. But the opinion that cats are able to see in absolute darkness has not been confirmed by scientists, although they see much better in the dark than during the day. The presence of a third eyelid in cats helps them make their way through bushes and grass while hunting, it wets the surface and protects from dust and damage. You can see it closely when the cat is half asleep and the film peeks through half-closed eyes. Another feature of cat vision is the ability to distinguish colors. For example, the main colors are blue, green, gray, and white and yellow can be confused.

How snakes see

Visual acuity, like other animals, snakes do not shine, since their eyes are covered with a thin film, due to which visibility is cloudy. When the snake sheds its skin, the film comes off with it, which makes the vision of snakes during this period especially distinct and sharp. The shape of the pupil of a snake can change depending on the way it hunts. For example, in night snakes it is vertical, and in daytime it is round. Whip-shaped snakes have the most unusual eyes. Their eyes are like a keyhole. Because of such an unusual structure of the snake's eyes, it skillfully uses its binocular vision - that is, each eye forms a complete picture of the world. The eyes of a snake can perceive infrared radiation. True, they “see” thermal radiation not with their eyes, but with special heat-sensitive organs.

How do crustaceans see

Shrimps and crabs, which also have compound eyes, have a feature that is not fully understood - they see very small details. Those. their eyesight is quite coarse, and it is difficult for them to see anything at a distance of more than 20 cm. However, they recognize movement very well.

It is not known why the mantis shrimp needs vision superior to other crustaceans, but this is how it developed in the process of evolution. It is believed that mantis shrimp have the most complex color perception - they have 12 types of visual receptors (humans have only 3). These visual receptors are located on 6 rows of various ommatidial receptors. They allow cancer to perceive circularly polarized light as well as hyperspectral color.

How monkeys see

color vision great apes trichromatic. Durukuls, leading a nocturnal life, have a monochromatic - with this it is better to navigate in the dark. The vision of monkeys is determined by lifestyle, nutrition. Monkeys distinguish between edible and inedible by color, recognize the degree of ripeness of fruits and berries, and avoid poisonous plants.

How horses and zebras see

Horses are large animals, so they need ample opportunities for the organs of vision. They have excellent peripheral vision, which allows them to see almost everything around them. That is why their eyes are directed to the sides, and not directly like in humans. But that also means they have a blind spot in front of their noses. And they always see everything from two parts. Zebras and horses see better at night than humans, but they see mostly in shades of gray.

How fish see

Each species of fish sees differently. For example, sharks. It seems that the eye of a shark is very similar to the human one, but it works in a completely different way. Sharks do not distinguish colors. The shark has an additional reflective layer behind the retina, which gives it incredible visual acuity. Shark sees 10 times better than a man in clean water.

Talking about fish in general. Basically, fish are not able to see beyond 12 meters. They begin to distinguish objects at a distance of two meters from them. Fish do not have eyelids, but nevertheless they are protected by a special film. Another of the features of vision is the ability to see beyond the water. Therefore, anglers are not recommended to wear bright clothes that can scare.

Reptiles. General information

Reptiles are characterized as cold-blooded animals, but this is not entirely accurate. Their body temperature is mainly determined by the environment, but in many cases they can regulate it and maintain it at a higher level if necessary. Some species are able to generate and retain heat within their own body tissues. Cold blood has some advantages over warm blood. Mammals need to maintain their body temperature at a constant level within very narrow limits. To do this, they constantly need food. Reptiles, on the contrary, tolerate a decrease in body temperature very well; their life interval is much wider than that of birds and mammals. Therefore, they are able to populate places that are not suitable for mammals, for example, deserts.

Once having eaten, they can digest food at rest. In some of the largest species, several months may pass between meals. Large mammals would not survive on this diet.

Apparently, among reptiles, only lizards have well-developed eyesight, since many of them hunt fast-moving prey. Aquatic reptiles rely more on the senses of smell and hearing to track prey, find a mate, or detect an approaching enemy. Their vision plays a secondary role and acts only at close range, visual images are vague, and there is no ability to focus on stationary objects for a long time. Most snakes have rather weak eyesight, usually only able to detect moving objects that are nearby. The numbing response in frogs, when approached by, for example, a snake, is a good defense mechanism, since the snake will not realize the presence of the frog until it makes a sudden movement. If this happens, then visual reflexes will allow the snake to quickly deal with it. Only tree snakes, which coil around branches and grab birds and insects in flight, have good binocular vision.

For snakes, the senses of taste and smell are very important. The quivering, forked tongue of a snake, which some people think of as a "snake's sting," actually collects traces of various substances quickly disappearing into the air and carries them to sensitive depressions on the inside of the mouth. There is a special device (Jacobson's organ) in the sky, which is connected to the brain by a branch of the olfactory nerve. Continuous extension and retraction of the tongue is an effective method of sampling the air for important chemical constituents. When retracted, the tongue is close to Jacobson's organ, and its nerve endings detect these substances. In other reptiles, the sense of smell plays a large role, and the part of the brain that is responsible for this function is very well developed. The organs of taste are usually less developed. Like snakes, Jacobson's organ is used to detect particles in the air (in some species with the help of the tongue) that carry the sense of smell.

The inner shell (amnion), immediately surrounding the embryo, is similar to the same shell in birds and mammals. The allantois is a more powerful membrane that acts as a lung and excretory organ. It provides the penetration of oxygen and the release of waste substances. Chorion is the shell that surrounds the entire contents of the egg. The outer shells of lizards and snakes are leathery, but those of turtles and crocodiles are harder and more calcified, like eggshells in birds.

The organs of infrared vision of snakes

Infrared vision in snakes requires non-local imaging

This organ works like a camera obscura, a prototype of cameras. A small warm-blooded animal on a cold background emits "heat rays" in all directions - far infrared radiation with a wavelength of about 10 microns. Passing through the hole, these rays locally heat the membrane and create a "thermal image". Due to the highest sensitivity of receptor cells (a temperature difference of thousandths of a degree Celsius is detected!) and good angular resolution, a snake can notice a mouse in absolute darkness from a fairly large distance.

From the point of view of physics, just a good angular resolution is a mystery. Nature has optimized this organ so that it is better to "see" even weak heat sources, that is, it simply increased the size of the inlet - aperture. But the larger the aperture, the more blurry the image turns out (we are talking, we emphasize, about the most ordinary hole, without any lenses). In the situation with snakes, where the aperture and depth of the camera are approximately equal, the image is so blurred that nothing but “there is a warm-blooded animal somewhere nearby” can be extracted from it. However, experiments with snakes show that they can determine the direction of a point source of heat with an accuracy of about 5 degrees! How do snakes manage to achieve such a high spatial resolution with such a terrible quality of "infrared optics"?

A recent article by German physicists A. B. Sichert, P. Friedel, J. Leo van Hemmen, Physical Review Letters, 97, 068105 (9 August 2006) was devoted to the study of this particular issue.

Despite the loud name, the approach used by them, of course, is not something fundamentally new, but just a kind of deconvolution - the restoration of an image spoiled by the imperfection of the detector. This is the reverse of motion blur and is widely used in computer image processing.

True, there was an important nuance in the analysis carried out: the deconvolution law did not need to be guessed, it could be calculated based on the geometry of the sensitive cavity. In other words, it was known in advance what kind of image a point source of light would give in any direction. Thanks to this, a completely blurred image could be restored with very good accuracy (ordinary graphic editors with a standard deconvolution law would not have coped with this task even close). The authors also proposed a specific neurophysiological implementation of this transformation.

Histological studies have shown that the pits do not contain specialized receptor cells, but unmyelinated trigeminal nerve endings, forming a wide non-overlapping branching.

The sensitivity is sufficient to detect the flow of radiation from a human hand moving into the "field of view" at a distance of 40 - 50 cm, which implies that the threshold stimulus is less than 8 x 10-5 W/cm 2 . Based on this, the temperature increase detected by the receptors is on the order of 0.005°C (i.e., about an order of magnitude better than the human ability to detect temperature changes).

"Heat-seeing" snakes

The black malakost (Malacosteus niger), which has a huge mouth, lives in complete darkness at depths from 915 to 1830 m and is a predator. How can he hunt in complete darkness?

Thanks to far red light, some fish can see in water that would appear black to us. A bloodthirsty piranha in the murky waters of the Amazon, for example, perceives the water as a dark red, a color more penetrating than black. The water looks red because of the particles of red vegetation that absorb visible light. Only beams of far red light pass through muddy water and can be seen by the piranha. Infrared beams allow her to see prey, even if she hunts in total darkness. Just like piranhas, crucian carp in their natural habitats often have fresh water that is cloudy, overflowing with vegetation. And they adapt to this by having the ability to see far red light. Indeed, their visual range (level) exceeds that of piranhas, since they can see not only in the far red, but also in true infrared light. So your favorite pet goldfish can see a lot more than you think, including the "invisible" infrared rays emitted by common household electronic devices such as TV remotes and burglar alarm beams.

Snakes strike prey blindly

It is known that many species of snakes, even when deprived of their sight, are able to strike their victims with supernatural accuracy.

Thus, scientists were able to prove the amazing ability of snakes to process even images that are very far from perfect. Now it is up to the validation of the model by studies of real snakes.

The snake is an animal of the chordate type, class reptiles, scaly order, suborder snakes (Serpentes). Like all reptiles, they are cold-blooded animals, so their existence depends on the ambient temperature.

Snake - description, characteristics, structure. What does a snake look like?

The body of the snake has an elongated shape and can reach a length of 10 centimeters to 9 meters, and the weight of the snake ranges from 10 grams to more than 100 kilograms. Males are smaller than females, but have more long tail. The body shape of these reptiles is varied: it can be short and thick, long and thin, and sea snakes have a flattened body that resembles a ribbon. Therefore, the internal organs of these scaly also have an elongated structure.

The internal organs are supported by more than 300 pairs of ribs movably connected to the skeleton.

The triangular head of the snake has jaws with elastic ligaments, which makes it possible to swallow large food.

Many snakes are venomous and use venom as a means of hunting and self-defense. Since snakes are deaf, for orientation in space, in addition to vision, they use the ability to capture vibration waves and thermal radiation.

The main information sensor is the forked tongue of the snake, which allows using special receptors inside the sky to “collect information” about environment. Snake eyelids are fused transparent films, scales that cover the eyes, therefore snakes don't blink and even sleep with their eyes open.

The skin of snakes is covered with scales, the number and shape of which depends on the type of reptile. Once every six months, the snake sheds old skin - this process is called molting.

By the way, the color of the snake can be monochromatic in species living in temperate zone, and motley among representatives of the tropics. The pattern may be longitudinal, transversely annular or spotted.

Types of snakes, names and photos

Today, scientists know more than 3,460 species of snakes living on the planet, among which the most famous are asps, vipers, sea snakes, snakes (not dangerous to humans), pit snakes, false-legged snakes that have both lungs, as well as rudimentary remains of pelvic bones and hind limbs.

Consider several representatives of the snake suborder:

King cobra (hamadryad) ( Ophiophagus hannah)

The most gigantic poisonous snake on the ground. Individual representatives grow up to 5.5 m, although the average size of adults usually does not exceed 3-4 m. King cobra venom is a deadly neurotoxin that is fatal in 15 minutes. The scientific name of the king cobra literally means "snake eater", because it is the only species whose representatives feed on their own kind of snakes. Females have an exceptional maternal instinct, constantly guarding the laying of eggs and completely do without food for up to 3 months. The king cobra lives in the tropical forests of India, the Philippines and the islands of Indonesia. Life expectancy is over 30 years.

Black Mamba ( Dendroaspis polylepis)

The African venomous snake, growing up to 3 m, is one of the fastest snakes, capable of moving at a speed of 11 km/h. The highly toxic snake venom results in death within minutes, although the black mamba is not aggressive and only attacks humans in self-defense. Representatives of the species black mamba got their name due to the black color of the oral cavity. Snake skin is usually olive, green, or brown in color with a metallic sheen. It eats small rodents, birds and bats.

Fierce Snake (Desert Taipan) ( Oxyuranus microlepidotus)

The most poisonous of land snakes, whose venom is 180 times stronger than poison cobra. This species of snake is common in the deserts and dry plains of Australia. Representatives of the species reach a length of 2.5 m. Skin color changes depending on the season: in extreme heat - straw, when it gets cold it becomes dark brown.

Gaboon viper (cassava) ( Bitis gabonica)

The poisonous snake that lives in the African savannas is one of the largest and thickest vipers up to 2 m long and with a body girth of almost 0.5 m. All individuals belonging to this species, have a characteristic, triangular-shaped head with small horns located between the nostrils. The Gaboon viper has a calm nature, rarely attacking people. Belongs to the type of viviparous snakes, breeds every 2-3 years, bringing from 24 to 60 offspring.

Anaconda ( Eunectes murinus)

The giant (ordinary, green) anaconda belongs to the subfamily of boas, in former times the snake was called that - a water boa. A massive body with a length of 5 to 11 m can weigh over 100 kg. A non-poisonous reptile is found in slow-flowing rivers, lakes and backwaters of the tropical part. South America, from Venezuela to the island of Trinidad. It feeds on iguanas, caimans, waterfowl and fish.

Python ( Pythonidae)

The representative of the family of non-venomous snakes is different giant size from 1 to 7.5 m in length, and female pythons are much larger and more powerful than males. The range extends throughout the eastern hemisphere: tropical forests, swamps and savannahs of the African continent, Australia and Asia. The diet of pythons consists of small and medium-sized mammals. Adults swallow leopards, jackals and porcupines whole, and then digest them for a long time. Female pythons lay their eggs and incubate the clutch, increasing the temperature in the nest by 15-17 degrees by muscle contraction.

African egg snakes (egg-eaters) ( Dasypeltis scabra)

Representatives of the snake family, feeding exclusively on bird eggs. They live in the savannas and woodlands of the equatorial part of the African continent. Individuals of both sexes grow no more than 1 meter long. The movable bones of the snake's skull make it possible to open the mouth wide and swallow very large eggs. In this case, the elongated cervical vertebrae pass through the esophagus and, like a can opener, open the eggshell, after which the contents flow into the stomach, and the shell is expectorated.

radiant snake ( Xenopeltis unicolor)

Non-venomous snakes, the length of which in rare cases reaches 1 m. The reptile got its name for the iridescent tint of the scales, which have a dark brown color. Burrowing snakes inhabit the loose soils of forests, cultivated fields, and gardens in Indonesia, Borneo, the Philippines, Laos, Thailand, Vietnam, and China. Small rodents and lizards are used as food objects.

Worm Blind Snake ( Typhlops vermicularis)

Small snakes, up to 38 cm long, outwardly resemble earthworms. Absolutely harmless representatives can be found under stones, melons and watermelons, as well as in bushes and on dry rocky slopes. They feed on beetles, caterpillars, ants and their larvae. The distribution zone extends from the Balkan Peninsula to the Caucasus, Central Asia and Afghanistan. Russian representatives of this species of snakes live in Dagestan.

Where do snakes live?

The distribution range of snakes does not include only Antarctica, New Zealand and the islands of Ireland. Many of them live in tropical latitudes. In nature, snakes live in forests, steppes, swamps, hot deserts and even in the ocean. Reptiles are active both during the day and at night. Species living in temperate latitudes hibernate in winter.

What do snakes eat in nature?

Almost all snakes are predators, with the exception of the Mexican herbivorous snake. Reptiles can only eat a few times a year. Some snakes feed on large and small rodents or amphibians, while others prefer bird eggs. The diet of sea snakes includes fish. There is even a snake that eats snakes: the king cobra can eat members of its own family. All snakes easily move on any surface, bending their body in waves, they can swim and “fly” from tree to tree, reducing their muscles.

Reproduction of snakes. How do snakes reproduce?

Despite the fact that snakes are solitary in their way of life, during the mating period they become quite sociable and “loving”. The mating dance of two opposite-sex snakes is sometimes so amazing and interesting that it definitely captivates attention. The male snake is ready to wind around his “chosen one” for hours, seeking her consent to fertilization. Reptile snakes are oviparous, and some snakes are able to give birth to live young. The size of the snake clutch varies from 10 to 120,000 eggs, depending on the type of snake and its habitat.

Reaching puberty by the age of two, snakes begin to mate. The male searches for his "lady" by smell, wraps his body around the female's neck, rising high above the ground. By the way, at this time, even non-poisonous individuals are very aggressive due to excitement and excitement.

Mating of snakes occurs in a ball, but immediately after this, the pair spreads out and never meets again. The snake parents show no interest in newborn cubs.

The snake tries to make its masonry in the most secluded place: plant roots, crevices in stones, rotten stumps - every quiet corner is important for the future "mommy". Laid eggs develop quite quickly - in just one and a half to two months. The snakes and serpents that were born are absolutely independent, poisonous individuals have poison, but these babies can only hunt small insects. Reptiles reach sexual maturity in their second year of life. The average life expectancy of a snake reaches 30 years.

What is snake venom? This is the saliva produced salivary glands poisonous individuals. Her healing properties known for hundreds of years: with the addition of snake venom, pharmacists make homeopathic preparations, creams, ointments and balms. These funds help with rheumatic diseases of the joints and with osteochondrosis. However, encountering a poisonous bite from this reptile in nature can be not only unpleasant and very painful, but also deadly.

What to do if bitten by a snake? First aid

If you were bitten by a snake, and at the same time you do not know whether it was poisonous or non-poisonous, in any case, you should remove the snake's saliva from the micro-wound! You can suck and quickly spit out the poison, you can squeeze it out, but all these manipulations will be effective only for the first one and a half minutes after the bite.
Definitely bitten must be urgently delivered to a medical facility (hospital).
At the same time, it is desirable to visually remember what the snake looked like, because its belonging to a certain species is most important for doctors who will prescribe an anti-snake serum to the victim.
If a limb (arm, leg) is bitten, then it does not need to be pulled: this manipulation does not localize the spread of snake venom, but it may well lead to toxic asphyxia of the affected tissues.
Never panic! The increased heart rate from excitement accelerates the blood throughout the body, thereby contributing to the spread of snake venom throughout the body.
Provide the bitten with absolute rest, warm drink and take him to professional doctors as soon as possible.

Comment from YariniCeteri

After you pass the bridge that slows you after the third boss you enter the "bazaar" area where you"ll see nearly 100 snekdudes patrolling throughout. In order to move on you need to grab two eyes, one on either side of the room, and deposit them into the skull at the far end of the room. stands to the skull within 10 seconds (which was our original understanding).

If you have an orb and are melee"d by any mob, it will drop the eye. In addition to the generic snekmob, there are special snekmobs called "Orb Guardians". Most of these are stealthed, but there"s 1 near each eye, 1 in between each eye and the skull, and 1-3 in the middle of the room. If the orbs are picked up they will forget ALL ELSE IN THE WORLD and go straight for the person holding the orbs. If they reach the person they'll knock the orb out of their hands and then pick it up, and then slowly run back to the stand the eye came from. The only way to get them to drop the eye is to kill them. We used this to our advantage, though our strat is heavily comp dependent.

What worked for us was to pick up one eye, allow it to be grabbed by an Orb Guardian, and then had our DK grip the add as far as he could get it. We continued gripping the add (took about 3 grips) until it was right next to the skull, then had one of our druids spam Entangling Roots on it to keep it from moving (essentially keeping one eye next to the skull) and then the rest of the group went over to the other eye and slowly got it across the room with grips as well. Once both eyes were near the skull, we killed all the Orb Guardians, and then grabbed both eyes and dropped them in together. Before you deposit the first eye be sure the second one is ready, because the Org Guardians respawn, and if you throw one in and then get the other one stolen by a brand new Orb Guardian, you likely won't kill it within 10 seconds .

Would love to hear how groups with other comps managed, since we basically lucked out with a very good comp (we actually ended up using Blood DK, Veng DH, Prot Pally, Feral Druid Resto Druid).

Also when the skull opens up and you don't get the achieve, don't be immediately worried. Ours didn't pop up for a good 5-10 seconds after the door was open.

My btag is FrostyShot#1667 if you have any questions about the metas. (US Servers)

Comment from nightswifty

For this achievement you will want to use class utility abilities to crowd control the Orb Guardian while you get both eyes closer. Note that there are several Orb Guardian throughout the room that will attempt to steal your eye back, there is one near each eye, one in between the eyes and the skull, and a few more in the middle of the room.

Comment from St3f

We used WL gate and the orb bugged into the ground. We couldn't open the door and progress further and had to skip the last boss. Pretty much all of the achievements in this dungeon are totally * [email protected]#ed.

Comment from Tatahe

This achiev is bugged, we got 2 guardians with orbs be next to the door, we killed both and then when we click the orbs to place it into the door, only one got there and the other despawned so we need to reset the instance cause the orb was completely missing it never respawned again...

Comment from Errno

My group got this after resetting the instance once because of an interesting bug.

We brought left orb to the right side so we can handle mobs better. We then started moving both orbs on the right side. At one point I decided to throw the orb, but it intersected with the other player holding the other orb. Instead of getting 2 debuffs / orbs on him or just not intersecting with him, the orb completely despawned. So we were one orb short and we couldn't even move on to the next boss. We had to reset the instance and clear all the way back. We were then very careful when throwing the orbs not to intersect them with the other orb holder so it won't bug. We also tried to keep the orbs a bit separated. After we got them close to snake head we just did a countdown and used them on the head at the same time. Achievement popped up after around 10 seconds even though we were all scratching our heads believing we somehow failed it.

So the strategy we used was:
1.Clear one side
2. Bring first orb to other side
3. Move orbs to head while killing/stunning mobs (to be safe don"t throw the orb or if you do careful it does not intersect with other orb holder).
4. Use at the same time and profit.

Comment from drlinux

This achievement is completely bugged!

We had to reset the instance 3 times, still no luck: Orbs keep bugging in, one disappears and only one will remain. Nothing can fix the issue, not even dying then running back to the eyes, they ain"t just magically reappear (at the 3rd try, we prayed to the God for the orbs to be there, buuuuuut nope)..
So yeah, you have to actually reset the whole instance and kill everything along the way, including the first three boss (because *giggle*...obviously, you can"t just simply skip them, why on the earth could you) - wasting time, and obviously getting no loot because of the reset.

Pro tip: If you move waaay TOO close to the skull, the orb will then be automatically thrown into the skull (without actually clicking on it)... thus resulting in a timer fail, if your other mate is too far away - by this "profiting" another nasty instance reset ( we had to learn this at our own mistakes). Now I don't know if it's a bug or not, but it's a good to know stuff.

Don "t get me wrong, I don" t have any problems with the mechanics, not even the quick respawn, and not even that the orb will be resetted if it "s on the ground for too long.. But come on, 2 orbs bugging into 1? ... That's ridiculous. For a moment I thought that maybe, just MAYBE if 2 orbs bugged into 1, perhaps that one orb would count as two (it does make sense, isn't it?).. but guess what: nope! :)

PS: already opened a ticket because this is the most annoying bugged achievement in my wow career...