What compensates for the poor development of vision and hearing in snakes. Infrared vision in snakes and its significance

Comment from YariniCeteri

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

Comment from St3f

Comment from Tatahe

Comment from Errno

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 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

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...

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

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

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

3. The organs of infrared vision of snakes .............................................. .................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 of the human body, a living optical instrument. 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 also the leaders night image The life of animals has its 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 the most amazing creations nature. 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 keeps many amazing secrets and they are waiting for their explorers. 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 have visual acuity several times higher than that of humans. 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 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. Some of the most large species several months may elapse 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 in more rely on senses such as smell and hearing to track down 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.

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 tissues 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 according to a program permanently hardwired into the nervous system.

In their work, the researchers proved that such a procedure is possible and quite real. They spent math modeling how a "thermal image" appears, and developed an optimal algorithm for repeatedly improving its clarity, dubbed 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.

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.

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 total 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 greatest length waves, 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, crucian carp in their natural habitats often have fresh water that is muddy, 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 the present infrared light. So your favorite home gold fish can see much more than you think, including the "invisible" infrared rays emitted by common household electronic devices such as the television remote control and the burglar alarm beam beam.

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. Research by scientists from the Munich technical university shows that it's probably because snakes have a unique "technology" for processing visual information, according to Newscientist.

Many snakes have sensitive infrared detectors that help them navigate in space. In the laboratory, the eyes of snakes were sealed with a band-aid, and it turned out that they were able to hit a rat. with an instant blow poisonous teeth in the neck of the victim 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.

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.

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.

Of all the many different animals living on Earth, snake eyes are able to distinguish colors and shades. Sight for the snake plays a big role in life, although it is not the main sense for getting to know the outside world. Serpents on our planet approx. As many people know from school, snakes belong to the scaly order. Their habitat is areas with a warm or temperate climate. .

How are the eyes of a snake arranged?

The snake eye, unlike other animals, does not differ in visual acuity. And all because their eyes are covered with a thin leathery film, they are very cloudy, and this greatly affects visibility. During molting, the snake parted with the old skin, and with it the film. Therefore, after molting, snakes are especially “big-eyed”. Their vision becomes sharper and clearer for several months. Because of the film on the eyes, people from ancient times gave the snake's gaze a special coldness and hypnotic power.

Most snakes that live near humans are harmless and do not pose any danger to humans. But there are also poisonous ones. Snake venom is used for hunting and protection.

Depending on the way of hunting - in the daytime or at night, the shape of the pupil of snakes changes. For example, the pupil is round, and the snakes leading the twilight hunt have acquired vertical and elongated eyes with long slits.

But the most unusual eyes have the appearance of whip-shaped snakes. Their eye is very similar to a keyhole located horizontally. 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.

But the main sense organ in snakes is still the sense of smell. This organ is the main one for thermolocation of vipers and pythons. The sense of smell allows you to catch the warmth of your victims in pitch darkness and accurately determine their location. Snakes that are non-venomous strangle or wrap their prey with their body, and there are those who swallow their prey alive. Most of the snakes are small, no more than one meter. During the hunt, the eyes of the snake are focused on one point, and their forked tongue, thanks to the Jacobson's organ, traces the subtlest smells in the air.

They do not have ears, but they react to every rustle. They don't have a nose, but they can sniff with their tongue. They can live for months without food and still feel great.
They are hated and deified, they are worshiped and destroyed, they are prayed to and with all this they are endlessly afraid. The Indians called them holy brothers, the Slavs - ungodly creatures, the Japanese - celestials of unearthly beauty ...
Snakes are not at all the most poisonous creatures on Earth, as most people think. On the contrary, the title of the most terrible killer belongs to the small South American leaf-climbing frogs. Moreover, according to statistics, every year more people die from bee stings than from snake stings.
snakes contrary to terrible myths about aggressive reptiles, the first to attack people and pursue them in a blind desire to sting, in fact - terribly shy creatures. Even among giant snakes, an attack on a person is an accidental and extremely rare phenomenon.

Seeing a person, the same vipers will first of all try to hide, hide, and they will definitely warn about their aggression, which is manifested, by hissing and false throws. By the way, the terrifying sweeps of the snake's tongue are not a threatening gesture at all. So the snake... sniffs the air! An amazing way to find out information about surrounding objects. In a couple of strokes, the tongue conveys the collected information to the sensitive serpentine palate, where it is recognized. And the snake - and this coincides with Chinese myths - is very prudent: it will never waste its poison in vain. She needs him herself - for real hunting and for defense. Therefore, most often the first bite is not poisonous. Even the king cobra often makes a blank bite.
It is the Indians who consider her a goddess endowed with great intelligence and wisdom.
By the way, it is cowardice that makes snakes and even spitting cobras feign death! In the face of a threat, these tricksters twist and fall on their backs, their mouths wide open and emitting unpleasant odors. All these subtle manipulations make the snake unattractive as a snack - and predators, disdainful of "carrion", go away. The Calabar boa acts even wiser: its blunt tail is very similar to the head. Therefore, sensing danger, the boa curls up into a ball, exposing its tail instead of a vulnerable head in front of the predator.
In fact, snakes that love to pretend to be dead are extremely tenacious creatures. There is a known case when an exhibit of a desert snake came to life in the British Museum! A copy that did not show signs of life was glued to a stand, and after a couple of years something was suspected. They peeled it off, placed it in warm water: the snake began to move, and then to eat with pleasure and lived for another two happy years.
No matter how attractive the legends about the bewitching snake look, in fact, these reptiles do not know how to hypnotize. The look of the snake is unblinking and fixed because it has no eyelids. Instead, there is a transparent film - something like glass on a watch - protecting the eyes of snakes from bruises, injections, litter, water. And no self-respecting rabbit will succumb to the "bewitching" look and dutifully wander into the mouth of a boa constrictor: the features of the snake's visual system are such that they allow it to see only the outline of moving objects. Only the rattlesnake was lucky: it has three sense organs on its head that help to find prey.
The rest of the members of the creeping family have extremely poor eyesight: frozen, potential victims immediately lose sight of the huntress. By the way, most animals - and those very notorious rabbits - perfectly use this, knowing the tactics of snake hunting. From the outside - a duel of views, but in fact, the snakes have to work hard before they manage to catch someone for dinner. Is it possible to hypnotize the snakes themselves? After all, everyone knows the picture of a cobra dancing in front of the caster.
I don't want to be disappointed, but this is also a myth. The snakes are deaf and do not hear the mournful music of the pipes. But very sensitively capture the slightest fluctuations in the surface of the earth next to them. The cunning spellcaster first lightly taps the basket with the snake or stomps, and the animal immediately reacts. Then, playing a motive, he continuously moves, sways, and the snake, constantly watching him, repeats his movements so that the person is always in front of his eyes. A spectacular sight, but the hypnotist from the caster, alas, is useless.
By the way, king cobras are well versed in music. Quiet melodious sounds soothe them, and the snakes, rising, slowly sway to the beat. The abrupt, sharp sounds of jazz, especially loud, unnerve the cobra, and it uneasily inflates its "hood". Heavy and even more “metal” rock leads the “music lover” into indignation: she stands on the tail and makes quick threatening movements in the direction of the music source. Recent studies by Russian herpetologists have shown that to the classical works of Mozart, Handel and Ravel, cobras dance with obvious pleasure, closing their eyes; but pop music causes lethargy, apathy and nausea.
By the way, about snake movements: it is interesting to observe how the body of a snake moves - there are no legs, nothing pushes, does not pull, but it slides and flows, as if without bones. In fact, the fact is that snakes are simply filled with bones - in some species, up to 145 pairs of ribs can be attached to a flexible spine! The peculiarity of the snake "gait" is given by the articulated spine, to which the ribs are attached. The vertebrae are attached to each other by a kind of hinges, and each vertebra has its own pair of ribs attached, which gives a unique freedom of movement.
Some Asian snakes can fly! They can famously climb to the tops of trees and from there soar down, spreading their ribs to the sides and turning into a kind of flat ribbon. If the heavenly tree snake wants to move from one tree to another, it literally flies to it without going down. In flight, they take an S-shape in order to stay in the air longer and get exactly where they need to be. As strange as it may sound, the tree snake is an even better glider than flying squirrels! Some flyers can cover distances up to 100 meters in this way.
By the way, all lovers of hot rumba should be grateful to snakes. There is a curious step in the dance: the gentlemen throw their legs far to the side and, as it were, crush someone. It comes from a dance movement from not so old times, when rattlesnake in Mexican dancing was quite commonplace. The imperturbable machos, in order to impress the ladies, crushed the uninvited guests with the heel of their boots. Then this movement became the highlight of the rumba.
There are countless beliefs about the magical power of the snake heart, which gives strength and immortality. In fact, hunters for such a treasure would have to sweat a lot in search of this very heart: after all, it can slide along the body of a snake! This miracle is bestowed by nature in order to make it easier for the snake to pass food through the gastrointestinal tract.
Despite the reverent fear of snakes, mankind, as is known, has been using their "gifts" for healing since ancient times. But there are more curious cases of how people - and not only - use the features of these amazing creatures for their own benefit. For example, owls sometimes place small snakes in their nests. They deal with small insects competing with owlets for prey brought by their mother. Thanks to the amazing neighborhood, the chicks grow faster and get sick less.
In Mexico, along with kittens and puppies, local “domestic” snakes are considered the favorites of children. They are herbivores and are covered with thick, shaggy hair. Brazilians prefer royal boas: in the houses of the suburbs of Rio de Janeiro and in the cottages of the mountain resort of Petropolis, these huge reptiles enjoy great love and respect. The fact is that there are a great many poisonous snakes in the country. But not a single poisonous individual will crawl into a garden where a boa constrictor is found, even if everything around is teeming with them. Moreover, boas are tenderly attached to children. As soon as the child leaves the house, the "nanny" begins to follow his every step. The boa constrictor invariably accompanies children on walks and during games, protecting the kids from snake attacks. Unusual governesses have saved thousands of lives with their devotion, especially in rural areas, where it is extremely problematic to deliver a life-saving serum. Kids respond to their guards with ardent reciprocity: boas are very neat, always have dry, pleasant to the touch and very clean skin, and it’s worth mentioning especially about unpretentiousness in everyday life: a boa constrictor eats once every two, or even four months, being content with the annual diet in an amount not exceeding five rabbits.
And on the Greek island of Kefalonia, snakes are not tamed, they are not used as a rodent exterminator or sekuditsy. It is on this day that small poisonous snakes with black crosses on their heads crawl into the temple from all around to the miraculous icon, before which the nuns once asked for intercession. What is amazing: they are drawn to the miraculous icon, as if spellbound, not afraid of people and not trying to bite them. People just as calmly react to unusual "parishioners" who crawl over the icons and without fear get over on their hands when they are extended to them. Even kids play with snakes. But soon after the end of the festive service, the snakes crawl off the icon of the Mother of God they love and leave the church. As soon as they crawl across the road and end up in the mountains, they again become the same: it’s better not to approach them - they will immediately hiss and bite! Yes, one can talk endlessly about these amazing creatures of nature: they stand apart in the animal world so much. And yet, in vain, for the most part, we do not like snakes so much. After all, the Chinese say that a person uses snakes with everything except hissing, and in return they receive nothing but hostility. Well, is that fair?

There are about three thousand snakes on earth. They belong to the scaly order and like to live in places warm climate. Many, walking through the forest in an area where snakes can live, wonder if they see us? Or should we look under our feet so as not to disturb the reptile? The fact is that among the diversity in the animal world, only the eyes of a snake are able to determine shades and colors, but their visual acuity is weak. For a snake, sight is, of course, important, but not in the same way as smell. In ancient times, people paid attention to the snake's eye, considering it cold and hypnotic.

How is the eye of a snake

Reptiles have very cloudy eyes. This is because they are covered with a film that changes during molting along with the rest of the skin. Because of this, snakes have poor visual acuity. As soon as reptiles shed their skin, their visual acuity immediately improves. During this period, they see the best. This is how they feel for several months.

Most people believe that all snakes are venomous. This is wrong. Most species are completely harmless. Poisonous reptiles use poison only in case of danger and when hunting. It takes place both during the day and at night. Depending on this, the pupil changes its shape. So, during the day it is round, and at night it is extended into a slot. There are whip snakes with a pupil in the form of an inverted keyhole. Each eye is able to form a whole picture of the world.

For snakes, the main organ is the sense of smell. They use it as a thermolocation. So, in complete silence, they feel the warmth of a possible victim and indicate its location. Non-poisonous species pounce on prey and choke it, some of them begin to swallow directly alive. It all depends on the size of the reptile itself and its prey. On average, the body of a snake is about one meter. There are both small and large species. Directing their gaze to the victim, they focus it. At this time, their tongue catches the slightest smells in space.