How snakes move. Snakes crawl due to an uneven coefficient of friction and constant redistribution of weight
American researchers have discovered the mechanism of movement of snakes. This was reported by Science NOW, and the researchers appeared in the journal Proceedings of the National Academy of Sciences.
At the first stage of the study, scientists studied the properties of the skin on the belly 10 king snakes Campbell ( Lampropeltis triangulum campbelli) - small reptiles about 35 centimeters long.
After tranquilizing them, the researchers moved the snakes around different surfaces. As a result, they were able to establish that when moving on a smooth surface, the friction force is approximately the same in all directions. If the surface is rough, then it is twice as difficult to move the snake sideways as it is forward. In addition, shifting backward is one and a half times more difficult than shifting forward.
If you try to tilt slippery surface, then the snake can overcome a maximum seven-degree inclination:
The scientists then studied videos of the snakes moving. Previously, scientists knew that while crawling, a snake sends a kind of “wave” through its body. The researchers were able to establish that during the passage of the “wave,” the reptile lifts some parts of the body, reducing the friction force on the surface in unnecessary places and increasing it where the body is repelled.
By putting the collected information into a computer, scientists received a model of a snake that moved as fast as its living counterparts:
According to the researchers, the new results can be used to create a new generation of robots that will be able to move like snakes. Such mechanisms can be useful, for example, in searching for and rescuing people trapped under the rubble of destroyed buildings.
The new work was positively received by experts in the field. Many note that the role of scales in the movement of snakes has been known for more than 60 years, but American researchers for the first time managed to put all the details of the movement of a reptile together and achieve a good agreement between the model and the real movement of the snake.
The movement of snakes is full of charming originality. The sight of a silently sliding writhing ribbon impresses the viewer indelible impression and provides aesthetic pleasure. However, the typical so-called “snake” movement is by no means the only method that snakes use. IN different conditions habitat, on different substrates various snakes developed a number of special types of movement. With the “serpentine” type of movement, the body bends in a wave-like manner and the resulting waves seem to run along the body from head to tail. The arching part of the body, placed obliquely to the direction of movement, rests on the substrate and creates a pushing force. It is directed at an angle to the movement, but can be decomposed into two components - perpendicular and parallel to the line of movement. The first component is dampened by the resistance of the support, and the second pushes the body forward.
Thus, the more bends, the greater the total driving force. Therefore, snakes that use this method of movement usually have a long, flexible and slender body. Such, for example, are snakes and snakes - active snakes, tracking and catching up with their prey. Let us note, however, that the speed developed by the Snake even during the fastest gliding does not, as a rule, exceed 6-8 km per hour, and in many species it does not even reach 5 km per hour. Therefore, a person can easily catch up with any snake if the competition takes place in an open space. Many readers are probably also interested in the opposite result: we can confidently guarantee that a snake cannot catch up with a person, even if it really wants to do so. However, this option is only of theoretical interest, since snakes never chase a person.
Since the serpentine type of movement uses support on the substrate, the efficiency of the movement depends on the roughness of the support. Thus, a snake cannot move on smooth glass: the body wriggles, but the animal remains in place. In addition to a smooth substrate, loose substrate - shifting desert sands not supported by vegetation - also provides poor support for the body. Under these conditions, some species of snakes ( sand faff, tailed viper, horned rattlesnake) has developed a special type of movement - “lateral movement”. Indeed, looking at the moving faff, you are convinced that it is crawling not forward, but as if sideways. Pulling the back part of the body forward, she throws it forward without touching the substrate and then, leaning on the entire side of the body, pulls up the front part. With such a movement, the trail is not continuous, but consists of separate parallel strips with hooked ends, located at an angle to the line of movement. With this method of movement, the support is more solid, and the snake literally “steps” from one track to another.
This type of movement is asymmetrical, so the load on the muscles is uneven. To equalize it, the snake has to periodically change the “working side” of its body - crawl either with its left or right side forward. Some species of snakes do not pursue prey, but guard it, lying motionless in ambush. Such snakes are inactive, and their body is usually thick and short. They are incapable of graceful snake-like movements, and they have to abandon this method, switching to a rectilinear or caterpillar type of movement. It is especially pronounced in large and short-bodied animals. African vipers(cassava, noise viper).
The body of a crawling viper does not bend at all, and when viewed from above, it seems that it is simply floating on the surface. From the side you can clearly see how ventral side a series of contractions and stretches runs through, propelling the snake forward. The zigzag pattern on the sides of the body seems to come to life, its angles either decrease or increase, and it seems that the viper “walks” on a dozen pairs of short legs. In the movement of snakes, especially with the latter method, important role expanded abdominal scutes play. They can fit tightly to each other, forming a smooth surface, or by contracting the abdominal muscles, their posterior edge is lowered and good support is created. By maneuvering its ventral scutes, the snake can create traction or vice versa; provide gliding on different parts of the body. The importance of the ventral scutes is confirmed by the fact that sea snakes, living their entire lives in aquatic environment, lost them. Their belly is covered with the same small scales as their back. And so, if such a snake is pulled onto land, it wriggles, but is almost unable to move on the solid substrate. In burrowing, swimming and tree snakes special specific adaptations for movement arise, which will be discussed when describing these species.
Snakes eat a wide variety of animals, from worms, mollusks and insects to fish, birds, rodents and small ungulates. All snakes are carnivorous, and the vast majority hunt live prey. Only individual species Sometimes they show a predilection for carrion (Persian viper, water muzzle). All snakes swallow their prey whole, without tearing or chewing it. Diet depends on the size of the snake; large species feed on correspondingly larger prey. The composition of food varies greatly with age: young individuals of most snakes feed on small invertebrates, and adults usually switch to feeding on vertebrates.
Only small species snakes (blind snakes, contia, etc.) feed on insects, worms, etc. all their lives. Many snakes limit themselves to certain foods, and sometimes the specialization goes so far as to cause dramatic changes in the structure of the skeleton of the dental system. For example, in the African egg snake, which feeds only bird eggs, the number of teeth has decreased and they have become small and blunt, and the processes of the vertebrae, perforating the esophagus, form a sharp “egg saw” that serves to cut the egg shell. Thanks to the extensibility of the mouth and body coverings, snakes can swallow prey that is 2-3 times thicker than themselves. However, these abilities also have their limits, and even a 10-meter boa constrictor or python cannot swallow an adult horse or cow, as “eyewitnesses” often report after returning from distant travels.
The largest animals ever swallowed by boa constrictors reached the size of a pig or roe deer. Snakes swallow captured prey alive if it is small and does not offer strong resistance. For large and strong prey they are used various ways killing, primarily strangulation with body rings. This technique is used by boa constrictors and most colubrid snakes. It is important to note that when strangulated, the boa constrictor does not crush the ribs of its victim, as is often described. It compresses the victim just enough to paralyze its breathing movements. A broken rib in the body of the prey would be fatal to the snake itself, since when swallowed it would easily pierce the snake's highly stretched skin. Therefore, the victim enters the stomach not only whole, but also undamaged.
Special and very effective method killing prey has worked out Poisonous snakes. Poisonous species are present in the family of already-like animals, but their poisonous teeth are located in the depths of the mouth and reach the victim’s body only when it is strongly captured by the snake’s mouth. Therefore, such species are forced to hold onto captured prey. U sea snakes, asps, vipers and pit vipers, the poisonous teeth are located in front, so that these snakes, having delivered a quick bite and injected a portion of poison into the victim’s body, can release the victim and wait for the poison to have its disastrous effect. The emergence of the poisonous apparatus is undoubtedly associated with the most important feature snake - swallowing large production entirely. Such prey must first be immobilized, and venom accomplishes this task in the most perfect way. In addition, introducing poison into the victim's body speeds up its digestion several times, since the poison from the inside destroys the tissues of the victim's body, preparing them for absorption.
It should be noted that snakes rarely develop truly impressive speeds. Most species move no faster than eight kilometers per hour, but the black mamba, for example, can crawl at a speed of sixteen to nineteen kilometers per hour.One of the main methods of movement is the accordion movement. The snake first gathers its entire body into folds, then, fixing the tip of its tail in one place, it pushes itself forward. After this, she pulls up the back of the body, gathering itself into folds again.
The second way to move is to move with a caterpillar. In this way, snakes move in a straight line and overcome some narrow places. With this method, the snake uses large scales located on its belly. She plunges them into the ground like small shovels. When the scale is in, the snake uses its muscles to move it towards the tail. As a result, the scales are pushed off the ground in turn, which allows the snake to move. This method is similar to rowing, which people use to move around in boats. The movement of the scales is similar to the movements.
Amazing sight
The characteristic writhing movement is used by snakes to move across fairly hard ground. To propel itself forward, the snake pushes against roots, stones, sticks and other hard objects, bending its body to the side. With this method of movement, the snake contracts its lateral muscles alternately, which allows it to crawl forward.Such wave-like movements are the basis of snake crawling. From the outside, this spectacle is mesmerizing. The reptile seems to lie motionless, but at the same time it flows forward for the eye. This feeling of lightness and imperceptibility of movement is deceptive. Snakes are amazingly strong creatures, their smooth movements are ensured by synchronized and measured work of muscles.
The fourth type of movement is called lateral movement or twisting. It is characteristic mainly of snakes living in the desert. Using this type of movement, they move through loose sand, and they do it surprisingly quickly. The lateral move is so called because first the snake’s head moves diagonally forward and to the side, and only then it pulls up the body. First it rests on the back of the body, then on the front. This type of movement leaves strange parallel marks on the sand with characteristic hooks at the ends of the segments.
There are other ways snakes can move. Paradise snakes, found in Indochina, Indonesia and the Philippines, live on palm trees. If they want to change their habitat, they simply fly to another tree. In reality, of course, they jump. Before the jump paradise snake takes a very deep breath to create an air chamber inside the body that acts as a parachute. This allows her to glide an impressive distance of up to thirty meters.
It is not known exactly when the legs disappeared during evolution in the ancestors of modern snakes, but on X-ray photographs one can still see rudimentary remains of the lower limbs.
Instructions
Since all snakes are active predators, the absence of legs did not affect their speed and agility. The limbs of snakes are replaced by scales that cover the body. Movements due to the adhesion of scales to the surface are divided into four main types.
Rectilinear movement (caterpillar). A group of scales on the ventral side of the animal pushes the snake’s body forward, plunging into the surface, like the oars of a boat, while the remaining scales create a stop. So, one after another, the scales first protrude, then are pressed by the force of movement of a special group of muscles, and the snake moves forward.
Wave-like lateral movement (squirming). The snake’s body seems to flow sideways, and an alternating contraction of the lateral muscles of the body occurs. All points of the animal’s body in contact with the surface constantly perform a series of sequential movements: push, carry, support. Due to these movements, a picture of rapid and easy movement is created. The number of vertebrae in snakes reaches 435, therefore, the number of bending points is approximately the same. How longer than the snake, the more powerful and faster it can move.
Lateral movement (twisting). The head of the reptile goes sideways and forward, then the body is pulled towards it. When leaning on the front part of the body, the back part is brought forward, then the cycle is repeated in reverse. It feels like a snake is walking. This is how the sand f-hole moves.
Methods of transportation
It may seem that it is very difficult to move without legs, but snakes do it masterfully. In fact, they know how to move on land in four main ways. If one method is not suitable, then they use another. Sometimes, especially on very flat surface , they have to try all four methods. The crawling of snakes can be quite rapid, and some of them are even capable of chasing their prey. However, even the fastest snakes rarely reach speeds exceeding 8 km/h. The crawling speed record is 16-19 km/h and belongs to.
black mamba
1. Accordion movement
One way the snake moves is called an accordion movement. First, the snake gathers its body into folds. Then, holding the tip of the tail in place, he pushes the front of the body forward. And finally tightens the back of the body.
2. Track movement
With the help of the caterpillar movement, the snake can move in a straight line.
She uses this movement when she needs to overcome some bottleneck. At the same time, the snake moves large scales located on its belly. One by one, the scales sink into the ground like small shovels. As soon as the scales sink into the ground, the muscles move them towards the tail.. During this movement, snakes alternately contract the muscles on their sides, so that their body bends in an S-shape: the snake wriggles and crawls.
Wave-like bending of the body is the most common way of snakes crawling. A calmly crawling snake is an amazingly beautiful and bewitching sight. Nothing seems to happen. The movements are almost imperceptible. The body seems to lie motionless and at the same time quickly flows. The feeling of ease of movement of a snake is deceptive. It's amazing in her
strong body
Many muscles work synchronously and measuredly, moving the body accurately and smoothly. Each point of the body in contact with the ground alternately finds itself in the phase of either support, push, or forward transfer. And so constantly: support-push-transfer, support-push-transfer... The longer the body, the more bends and the faster the movement. Therefore, during the course of evolution, the body of snakes became longer and longer. In this regard, they are record holders among vertebrate animals. The number of vertebrae in them can reach 435 (in humans, for comparison, only 32-33).
4. Twisting or sideways movement - This is a method of movement that is used only by some species of snakes living in the desert. Using this method, they can move quickly through loose sand, and they move so quickly that it is difficult to follow them. In this case, the snake’s head goes sideways and forward, and then the body is pulled up. Snakes begin to almost walk, if one can say so about completely legless creatures: leaning on the back part of the body, they carry the front part forward, then vice versa. In this case, very strange marks appear in the form of oblique parallel stripes with hooks at the end. You wouldn’t immediately guess that such a trace could be left
Living being ! It is in this way that the sand faff moves - very dangerous snake
Some snakes are even capable of jumping forward, first gathering their body into rings, like a spring, and then sharply straightening it.
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