What is molting
Shedding (general definition)- the process of changing the integument of animals, which has a diverse nature.
Among invertebrates, typical molting occurs in nematodes, cephalopods, arthropods and related groups. In most of these animals, molting is regulated by the hormone ecdysone 1. Since, according to molecular phylogenetics, these groups are related to each other, they have recently been combined under the name Ecdysosoa- Shedding. In these groups, molting is reduced to periodic shedding and replacement of the cuticle. Before molting, the inner layers of the old cuticle dissolve, and underneath the hypodermal cells secrete a new cuticle. After a molt, the animal rapidly increases in size (usually by absorbing water or "inflating" with air) until the new cuticle hardens, after which growth ceases until the next molt (periodic growth).
Nematodes have larvae that molt (usually there are four larval stages); adult nematodes do not grow or molt. In most groups of arthropods (crustaceans, spiders, etc.), molting and growth continue throughout life.
Molting in insects, as a rule, is repeated at the larval stage; In insects with complete metamorphosis, during the last molt the larva turns into a pupa, and after shedding the pupa's integument, the insect turns into an adult form - an imago. In insects with incomplete metamorphosis, during the last molt the larva turns into an adult (only mayflies have a winged subimago stage, which molts one more time before turning into an adult insect. Adult insects do not grow or molt.
Among vertebrates, molting occurs in all tetrapods. Frogs and toads molt, shedding several layers of keratinized epithelial cells. Molting is also typical for representatives of reptiles. Among reptiles, snakes periodically shed their entire horny cover, and the so-called. “crawl” - the shed “skin” of a snake. When birds molt, their plumage changes, and in temperate and subpolar latitudes, seasonal molting occurs (in spring and autumn) - a change from winter to summer plumage. Sometimes its color changes (snowy owl, white partridge). In mammals living in temperate latitudes, as a rule, molting also occurs twice a year - in the spring, when thick winter fur is shed, and in the fall, when the warm winter coat grows. The color of this cover often changes, for example, in hares, squirrels, etc.
1 Ecdysones(from Greek ekdysis- molting) - hormones belonging to the group of steroids (27-28 carbon atoms), stimulating molting and metamorphosis of arthropods.
Shedding in snakes
Normally, molting is a complex process in which the cells of the intermediate zone of the epidermis (several outer layers of living cells located under the stratum corneum) proliferate and form a new stratum corneum, called the inner epidermal generation. Roughly speaking, this is a biological process during which a reptile forms a new cover and sheds the old one.
Reptiles, in particular snakes, take quite a long time to prepare to “change their skin,” become restless, and lose their appetite. The time preceding molting is called the “blue eyes” period by herpetologists. At the same time, the snake skin looks lifeless, dulls, fades, the pattern on it loses its clarity, and the eyes become dull blue. The behavior of animals during this period also changes: some become lethargic and move little, others are nervous and show increased aggressiveness. Poisonous snakes are especially dangerous: if accidentally disturbed, they can actively attack and try to bite.
Cheney's carpet python (Morelia Spilota cheynei), a juvenile with cloudy eyes
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White-lipped python (lat. Leiopython albertisii), juvenile with cloudy eyes
In most snakes, shedding begins from the head, with the exception of burrowing snakes of the family Typhlopidae, which shed from the tail. At the same time, the exfoliated covers begin to slide, stretching and tearing off in the form of more or less long tubes. The discarded old “stocking” of blind puppies does not turn inside out. Normally, the snake sheds quickly and completely. The discarded skin is called a “creep” and is an almost complete cover, which is several cm longer than the snake’s body. Very large snakes shed with a “crawl” break under the weight of their weight. Lumpy shedding occurs in snakes that are sick or live in unfavorable conditions (for example, with insufficient air humidity). It is especially important to have transparent “glasses” on the crawl - the stratum corneum from the eyes, since its untimely descent can cost the animal its vision: squeezing the eyeball leads to its inflammation and even death.
Snake crawls
The first molt in baby snakes occurs either immediately after birth, which is typical for viviparous and ovoviviparous species, or 7 to 14 days after hatching from the egg (for oviparous snakes). Then the young animals molt every 3-4 weeks, as they actively feed and grow. With age, the frequency of molts decreases, and the intervals between them increase. Adult snakes shed their old skin once every 3-6 months, and some species living in difficult natural conditions (for example, in high mountains) shed only once a year. A snake that has just shed its skin has a beautiful, bright and clear coloration.
Normal shedding goes through several stages:
Proliferation stage. At this point, the skin becomes dull and matte. In snakes this stage is little noticeable.
Demolting phase. Includes the formation of internal epidermal generation and the formation of a cavity with lymph effusion into it. Proliferation is replaced by differentiation of cells that make up the new stratum corneum at the periphery of the proliferate with the formation of a thin gap in the intermediate zone (between three layers of old and three layers of new cells). After the formation of the internal epidermal generation of cells, a cavity is formed - a zone of stratification. During this time, you can observe clouding of the eyes of snakes. The so-called “blue eyes” period.
The phase of separation. During it, the skin brightens and is almost no different from normal. In the phase of separation, lysis (dissolution) of the interstitial substance and adhesion (sticking together) of proteins occurs, followed by molting.
Violation of shedding in snakes
Usually snakes shed their old skin in a very simple way: they crawl out of it. The outer layer of the snake's skin is a single unit, from the glasses on the eyes to the tip of the tail. The first sign of shedding in snakes is cloudy eyes. But in fact, first there is clouding of the abdominal scutes, which takes two to four days. Then the eyes become cloudy for one to five days. The eyes become milky white later, and this color disappears earlier than in other parts of the body, which is of vital importance for the snake, since it sees poorly at this time. The third stage is the clearing of the eyes, the fourth stage is the clearing of the abdominal scutes and, finally, the last, fifth stage is the actual molting. Preparation for it takes from five to twelve days, the third and fourth stages are often quite short.
Before molting, many snakes lose their appetite and become irritable. Many species living in nature go in search of water in which to soak.
In healthy snakes, molting itself takes from thirty minutes to several hours. It begins after the snake peels off the old cuticle on its lips by rubbing the tip of its snout on some rough surface. Then the snake begins to move the skin back from its head and, crawling among the bushes and stones, gradually, centimeter by centimeter, pulls off the old skin. Along with her old clothes, she also throws off the “glasses” that protect her eyes.
Patterned runner (lat. Elaphe dione) in the process of shedding the old skin
Based on materials from the sites: http://ru.wikipedia.org/, http://www.zmeuga.ru/ and the works of Vasiliev D.B.
Normally, molting is a complex process in which the cells of the intermediate zone of the epidermis (several outer layers of living cells located under the stratum corneum) proliferate and form a new stratum corneum, called the inner epidermal generation. Molting is a biological process during which a reptile forms a new coat and sheds the old one.
Reptiles, in particular snakes, take quite a long time to prepare to “change their skin”, become restless, and lose their appetite. The time preceding molting is called the “blue eyes” period by herpetologists. At the same time, the snake skin looks lifeless, dulls, fades, the pattern on it loses its clarity, and the eyes become dull blue. The behavior of animals during this period also changes: some become lethargic and move little, others are nervous and show increased aggressiveness. Poisonous snakes are especially dangerous: if accidentally disturbed, they can actively attack and try to bite.
Normally, the snake sheds quickly and entirely. The shed skin is called a “creep” and is an almost complete sheath, which is several cm longer than the snake’s body. Very large snakes shed with a “crawl” break under the weight of their weight. Lumpy shedding occurs in snakes that are sick or live in unfavorable conditions (for example, with insufficient air humidity). It is especially important to have transparent “glasses” on the “creep” - the stratum corneum from the eyes, since its untimely descent can cost the animal its vision: squeezing the eyeball leads to its inflammation and even death.
The stages that a snake goes through during normal molting.
Proliferation stage. At this point, the skin becomes dull and matte. In snakes this stage is little noticeable.
Demolting phase. Includes the formation of internal epidermal generation and the formation of a cavity with lymph effusion into it. Proliferation is replaced by differentiation of cells that make up the new stratum corneum at the periphery of the proliferate with the formation of a thin gap in the intermediate zone (between three layers of old and three layers of new cells). After the formation of the internal epidermal generation of cells, a cavity is formed - a zone of stratification. During this time, you can observe clouding of the eyes of snakes. The so-called “blue eyes” period.
Delamination phase. During it, the skin brightens and is almost no different from normal. In the phase of separation, lysis (dissolution) of the interstitial substance and adhesion (sticking together) of proteins occurs, followed by molting.
Usually snakes shed their old skin in a very simple way: they crawl out of it. The outer layer of the snake's skin is a single unit, from the glasses on the eyes to the tip of the tail. The first sign of shedding in snakes is clouding of the eyes. But in fact, first there is clouding of the abdominal scutes, which takes two to four days. Then the eyes become cloudy for one to five days. The eyes become milky white later, and this color disappears earlier than in other parts of the body, which is of vital importance for the snake, since it sees poorly at this time. The third stage is the clearing of the eyes, the fourth stage is the clearing of the abdominal scutes and, finally, the last, fifth stage is the molting itself. Preparation for it takes from five to twelve days, the third and fourth stages are often quite short.
Before molting, many snakes lose their appetite and become irritable. Many species living in nature go in search of water in which to soak.
In healthy snakes, molting itself takes from thirty minutes to several hours. It begins after the snake peels off the old cuticle on its lips by rubbing the tip of its snout on some rough surface. Then the snake begins to move the skin back from its head and, crawling among the bushes and stones, gradually, centimeter by centimeter, pulls off the old skin. Along with her old clothes, she also throws off the “glasses” that protect her eyes.
Molting is disrupted by diseases accompanied by dehydration of the body, low air humidity in the terrarium, vitamin deficiencies, excessive ultraviolet irradiation of snakes, and the absence of objects that facilitate the removal of the old skin - stones, snags, etc.
When molting problems occur, it is necessary to establish their cause and eliminate it. However, in the beginning, you usually have to help the snake shed its no longer needed skin. To do this, the snake is fixed and, using tweezers with thin ends, the old skin is removed first from the head: the exfoliated epidermis is separated in the corners of the mouth, then from the upper and lower labial scutes. Then they take the epidermis from the handkerchief with tweezers and remove it from the top of the head, taking special care when removing old skin from the nostrils and from the eyes of the snake, “glasses”. Next, the lower jaw of the reptile is freed from the skin. The skin is removed from the body with a free hand, just as it happens during natural molting. To facilitate the whole procedure, the snake is placed for several hours in a warm bath, the water temperature in which is about 27-28 degrees, and 4 grams of baking soda are dissolved in each liter.
Sometimes the only problem with molting is that old “glasses” remain on the reptile’s eyes. As a result, a thick layer of such “glasses” can form, which begin to put pressure on the cornea of the eyes. You can try to remove these “glasses” using fine-tipped tweezers and a magnifying glass, and after moistening the scales. However, if new “glasses” are accidentally removed, inflammation of the cornea develops – keratitis, which often results in blindness. To avoid this, you need to wait until the next molt. When preparing the reptile for it, it is necessary to increase the air humidity in the terrarium and periodically spray the animal with water. Later, when the molting itself should begin, the snake is placed in water, and its eyes are irrigated with a 20% solution of acetylcysteine, 5 milliliters of it are diluted with distilled water.
Pathological molting can be caused by improper living conditions for snakes. The microclimate in the terrarium plays a huge role, and, first of all, humidity: both its increase and decrease affects molting pathologically. With high humidity, the skin of reptiles is affected by bacterial and fungal microflora, which in turn can cause skin erosion. With low humidity, dead skin does not come off completely, and its remaining areas can form so-called rings on the body, which, squeezing blood vessels and nerves, can cause necrosis. When molting, the skin of snakes also comes off from the head; when the humidity is low, the keratinized areas do not come off from the eyes, which leads to partial blindness.
The second factor of improper maintenance conditions that cause pathological molting is traumatic utensils in the terrarium. If the reptile's skin is often injured by various kinds of objects, this can provoke disruption of the molting process. Often the skin is injured when feeding live food. The teeth of small mammals intended for feeding snakes can injure soft tissues, which leads to the formation of microabscesses (ulcers), leading to disruption of the molting process. Also, mechanical damage to the skin includes burns that animals receive when touching heating devices, and any burn, as a result, is a violation of molting.
Often the molting process is disrupted in animals due to a lack of macro-, microelements and vitamins. With improper feeding and a prolonged absence of food, pathological changes can occur in the animal’s body, which in turn can lead to disruption of molting. Overfeeding is also harmful, since it can result in obesity in the reptile, and too rapid body growth can lead to the fact that the animal’s body will not have enough biologically active substances for timely reproduction of the skin.
With proper and balanced feeding of snakes, as well as normal conditions for keeping them, the molting process occurs regularly and without pathologies.
I just want to add a phrase here to give it to lovers of fashionable wallets.
Yes, it’s true, the snake sheds its own skin, and if anyone has ever observed this in nature, they will say that the process of getting rid of old skin from a snake is like something out of a horror movie.
Wriggling, she tears her own skin near her mouth and on her head, inflicting wounds on herself, then with her torn skin she clings to some twig or sharp stone and crawls out of her skin, leaving it turned inside out, as if it were a child’s stocking.
At the same time, the snake wriggles in such a way that it seems to the uninitiated viewer that it is experiencing unbearable pain. We don’t know whether a snake shedding its skin feels pain, most likely not, skin replacement is a natural physiological process, compare molting in animals, nature probably saved the snake from unpleasant sensations.
So why do snakes perform this terrible ritual on themselves? That's the whole point. that the snake is growing, and its skin is like clothing, it becomes tight. It rubs and wears from crawling on the ground, protecting the snake's delicate body from wounds as it crawls. New skin grows under the old skin and therefore the snake sheds it.
At a young age, snakes grow quickly, which means they are more often forced to get rid of the old skin that has become tight to them. And let animal lovers not be angry, the snake itself gives leather for wallets to lovers of all things extravagant. Isn't it true?
P.S. Just for fun
- My dear, give me money for peeling!
- What is peeling?
- This is when you remove the old skin, and underneath it is new - smooth and beautiful!
- And I always thought that you snakes shed for free!
They say that the biblical serpent was very sorry when he tempted Adam and Eve with an apple.
- Why?
- After Eve took a bite of the apple, she saw in the Snake not only an animal, but also a belt, a wallet and a handbag.
Most reptiles exchange their old skin for new ones from time to time. This renewal process is called molting and occurs differently in all reptiles. Snakes were no exception, shedding not only all their skin, but even the film covering their eyes.
Why does a snake change its skin?
For a long time it was believed that another reason for the change in skin is that the snake’s body grows, but its skin does not, so it has to be shed and acquired a new, larger one. Currently, this fact raises doubts among scientists.
How does a snake change its skin?
So how does a snake shed its old skin and get a new one? The snake grows new skin underneath the old one, and when the growth process is complete, the old skin begins to stretch and separate from the new one. First, the old skin bursts around the mouth, and the snake begins to rub its head against various hard surfaces and wriggle, trying to pull it off. When the snake manages to free its head, it simply crawls out of its old skin, turning it inside out. The discarded old skin looks like an almost complete case, which, by the way, after discarding, turns out to be several cm longer than the owner’s body.
How does a snake prepare for molting?
How does a snake change its skin? She prepares for this process for a very long time - she becomes restless, stops eating, and her behavior changes. Some snakes become lethargic and lazy, while others, on the contrary, become nervous and very aggressive. Poisonous snakes are especially dangerous during the molting period.
The fact that the snake is preparing to shed is noticeable externally: its old skin fades and dulls, the pattern on it is no longer so clear, and its eyes acquire a dull blue tint. This time is called the “blue eye period” and it lasts on average 7 days.
How often does a snake change its skin?
It is through this process of constant skin renewal that the snake has become a symbol of medicine and healing.
Snakes take quite a long time to prepare for the molting process. They become anxious, move around a lot and lose their appetite. The skin on their body gradually becomes pale, dull, and the ornament loses its clarity. Gradually, the dying skin begins to peel off, which is practically unnoticeable, and then the snake removes the dead skin with a “stocking”, as if crawling out of it.
A molting snake's eyes turn a dull blue, which is why herpetologists call this time the "blue eye period." Reptiles at this time become either very lethargic or, on the contrary, aggressive; poisonous representatives of the species are especially dangerous in this state. If they are even slightly disturbed, they can attack the “offender” and will definitely bite him.
Most snakes begin to shed from the head, and only burrowing representatives of the blind snake family begin to shed from the tail. A healthy snake sheds its old skin quite quickly and completely. The shed cover is called a “creep”; it is a single cover, the size of which is a couple of centimeters greater than the length of the snake’s body, since it stretches when shed.
In large snakes, the weight of the crawler may tear in some places. It is very important that the clear areas of the eyes are present on the shed skin, since untimely removal of the stratum corneum from these areas can result in serious vision problems for the reptile. Under pressure from the stretched old layer, the eyeball becomes inflamed, which can lead not only to diseases of the organs of vision, but also to blindness and even the death of the animal.
Disturbances in the molting process in snakes can be observed under improper housing conditions. For example, the microclimate in the terrarium, primarily air humidity, is of great importance for the good condition of the reptile. An increase or decrease in this indicator provokes skin problems and diseases, and, consequently, pathological changes during the molting process.
With an increase, the skin is affected by bacteria and fungi, as a result, erosion appears on it, and, therefore, the old cover comes off much more difficult. With low humidity, the skin dries out and therefore does not come off completely, but in parts. As a result, some fragments may remain on the body and form rings that compress areas of the body, squeezing blood vessels and nerves. This situation can result in necrosis. Low humidity also makes it difficult for dead skin to shed from the eyes, which can lead to blindness and even death.
Injured skin of a reptile can also disrupt the natural course of molting. Most often this happens due to the presence in the terrarium of objects potentially dangerous to the snake. This is, first of all, live food. Mammals intended for feeding can injure the snake's soft tissues with their teeth. This leads to microabscesses and disrupts the molting process. Skin injuries can also result from burns from heating or lighting devices.
Lack of vitamins, macro- and microelements also lead to pathological molting. If there is a long absence of food or the reptile’s diet is incorrect, molting may not proceed correctly. Excessive nutrition, leading to obesity or increased growth rate of the animal, leads to the fact that the snake will not have enough biologically active substances to form new skin.
