How fast does a lizard grow a new tail. How a lizard sheds its tail

Regeneration of lost organs in animals is a mystery that has been exciting scientists since ancient times. Until recently, it was believed that only the lower species of living beings were endowed with this magnificent property: a lizard grows a severed tail, some worms can be cut into small pieces, and each will grow into a whole worm - there are many examples.

But after all, the evolution of the living world went from lower organisms to more and more highly organized ones, so why did this property disappear at some stage? And did it disappear?

The Lernean Hydra, the Gorgon Medusa, or our three-headed Serpent Gorynych, whose heads Ivan Tsarevich tirelessly cut off “self-healing” heads, are characters, although mythical, but clearly in “family relations” with quite real creatures.

These, for example, include newts - a kind of tailed amphibians, which are rightfully considered one of the most ancient animals on Earth. Their amazing feature is the ability to regenerate - to grow damaged or lost tails, paws, jaws.

Moreover, their damaged heart, eye tissues, and spinal cord are restored. For this reason, they are indispensable for laboratory research, and newts are sent into space no less often than dogs and monkeys. Many other creatures have the same properties.

Thus, black-and-white zebrafish, only 2-3 cm long, tend to regenerate parts of their fins, eyes, and even restore their own heart cells, excised by surgeons in the process of regeneration experiments. This can be said about other types of fish.

Classical examples of regeneration are lizards and tadpoles that regenerate their lost tails; crayfish and crabs regrowing lost claws; snails capable of growing new "horns" with eyes; salamanders, which naturally replace an amputated leg; starfish regenerating their torn off rays.

By the way, a new animal can develop from such a severed ray, like from a cutting. But the flatworm, or planaria, became the champion of regeneration. If it is cut in half, then the missing head grows on one half of the body, and the tail on the other, that is, two completely independent viable individuals are formed.

And perhaps the appearance of a completely unusual, two-headed and two-tailed planaria. This will happen if you make longitudinal cuts at the front and rear ends and prevent them from growing together. Even from 1/280 of the body part of this worm, a new animal will turn out!

People watched our smaller brothers for a long time and, to be honest, secretly envied. And scientists moved from fruitless observations to analysis and tried to identify the laws of this "self-healing" and "self-healing" of animals.

The first to try to bring scientific clarity to this phenomenon was the French naturalist Rene Antoine Réaumur. It was he who introduced the term "regeneration" into science - the restoration of a lost part of the body with its structure (from Latin ge - "again" and generatio - "emergence") - and conducted a series of experiments. His work on the regeneration of legs in cancer was published in 1712. Alas, colleagues did not pay attention to her, and Réaumur left these studies.

Only 28 years later, the Swiss naturalist Abraham Tremblay continued his experiments on regeneration. The creature on which he experimented did not even have its own name at that time. Moreover, scientists did not yet know whether it was an animal or a plant. A hollow stalk with tentacles, with its posterior end attached to the glass of an aquarium or to aquatic plants, turned out to be a predator, and a very surprising one at that.

In the experiments of the researcher, individual fragments of the body of a small predator turned into independent individuals - a phenomenon known until then only in flora. And the animal continued to amaze the naturalist: in place of the longitudinal cuts at the front end of the calf made by the scientist, it grew new tentacles, turning into a “many-headed monster”, a miniature mythical hydra, with which, according to the ancient Greeks, Hercules fought.

Not surprisingly, the laboratory animal received the same name. But the hydra in question had even more wondrous features than its Lernean namesake. She grew to a whole even from 1/200 of her one-centimeter body!

Reality surpassed fairy tales! But the facts that are known today to every schoolchild, published in 1743 in the Proceedings of the Royal Society of London, seemed implausible to the scientific world. And then Tremblay supported by this time the already authoritative Réaumur, confirming the reliability of his research.

The "scandalous" topic immediately attracted the attention of many scientists. And soon the list of animals with the ability to regenerate was quite impressive. Truth, for a long time it was believed that only lower living organisms possess a mechanism of self-renewal. The scientists then discovered that birds can grow beaks, while young mice and rats can grow tails.

Even mammals and humans have tissues with great potential in this area - many animals regularly change their hair, the scales of the human epidermis are renewed, cut hair and shaved beards grow.

Man is not only an extremely inquisitive being, but also passionately desiring to use any knowledge for his own good. Therefore, it is quite understandable that at a certain stage in the study of the mysteries of regeneration, the question arose: why is this happening and is it possible to cause regeneration artificially? And why did the higher mammals almost lose this ability?

First, experts noted that regeneration is closely related to the age of the animal. The younger it is, the easier and faster the damage is repaired. In a tadpole, the missing tail easily grows back, but the loss of a leg by an old frog makes it disabled.

Scientists studied physiological differences, and the method used by amphibians for "self-repair" became clear: it turned out that on early stages development cells of the future creature are immature, and the direction of their development may well change. For example, experiments on frog embryos have shown that when an embryo has only a few hundred cells, a piece of tissue destined to become a skin can be cut out of it and placed in a region of the brain. And this tissue... will become part of the brain!

If such an operation is performed on a more mature embryo, then skin cells still develop into skin - right in the middle of the brain. Therefore, scientists concluded that the fate of these cells is already predetermined. And if for the cells of most higher organisms there is no way back, then the cells of amphibians are able to turn back time and return to the moment when the destination could change.

What is this amazing substance that allows amphibians to “repair themselves”? Scientists have found that if a newt or salamander loses a leg, then in the damaged area of ​​\u200b\u200bthe body, the cells of bones, skins and blood lose their distinctive features.

All secondarily "newborn" cells, which are called blastema, begin to intensively divide. And in accordance with the needs of the body, they become cells of bones, skin, blood ... to become a new paw at the end. And if at the time of "self-repair" you connect tretinoic acid (vitamin A acid), then this spurs the regenerative abilities of frogs so much that they grow three legs instead of one lost.

For a long time it remained a mystery why the regeneration program was suppressed in warm-blooded animals. There may be several explanations. The first is that warm-blooded animals have slightly different survival priorities than cold-blooded ones. Scarring of wounds became more important than total regeneration, as it reduced the chances of fatal bleeding when injured and the introduction of a deadly infection.

But there may be another explanation, much more gloomy - cancer, that is, the rapid restoration of a vast area of ​​damaged tissue implies the appearance of identical rapidly dividing cells in a certain place. This is exactly what is observed in the occurrence and growth of a malignant tumor. Therefore, scientists believe that it has become vital for the body to destroy rapidly dividing cells, and therefore, the ability to quickly regenerate was suppressed.

Doctor of Biological Sciences Petr Garyaev, Academician Russian Academy of medical and technical sciences, states: “It (regeneration) did not disappear, just higher animals, including humans, turned out to be more protected from external influences and complete regeneration became not so necessary.”

To some extent, it has been preserved: wounds and cuts heal, peeled skin is restored, hair grows, and the liver partially regenerates. But the torn off hand no longer grows in us, just as internal organs do not grow to replace those that have ceased to function. Nature has simply forgotten how to do it. Perhaps she should be reminded of this.

As always, His Majesty Chance helped. Philadelphia-based immunologist Helen Heber-Katz once gave her lab assistant a routine task: pierce the ears of lab mice to label them. A couple of weeks later, Heber-Katz came to the mice with ready-made labels, but ... she did not find holes in the ears.

Did it again - got the same result: no hint of a healed wound. The body of mice regenerated tissues and cartilage, filling in the holes they did not need. Herber-Katz made the only correct conclusion from this: in the damaged areas of the ears there is a blastema - the same non-specialized cells as in amphibians.

But mice are mammals, they should not have such abilities. Experiments on unfortunate rodents continued. Scientists cut off pieces of tails to mice and ... got 75 percent regeneration! True, no one even tried to cut off the paws of the "patients" for the obvious reason: without cauterization, the mouse would simply die from large blood loss long before the regeneration of the lost limb began (if at all). And cauterization excludes the appearance of a blastema. So that full list The regenerative abilities of mice could not be elucidated. However, we have already learned a lot.

True, there was one "but". These were not ordinary house mice, but special pets with a damaged immune system. Heber-Katz made the following conclusion from her experiments: regeneration is inherent only in animals with destroyed T-cells - cells of the immune system.

Here is the main problem: amphibians do not have it. So, it is from the immune system that the key to this phenomenon is rooted. Conclusion two: mammals have the same genes necessary for tissue regeneration as amphibians, but T-cells do not allow these genes to work.

Conclusion three: organisms originally had two ways of healing from wounds - the immune system and regeneration. But over the course of evolution, the two systems became incompatible with each other - and mammals chose T-cells because they are more important, since they are the body's main weapon against tumors.

What's the point of being able to regrow your lost arm if cancer cells are thriving in your body at the same time? It turns out that the immune system, while protecting us from infections and cancer, at the same time suppresses our ability to "self-repair".

But is it really impossible to think of anything, because you really want not just rejuvenation, but the restoration of life-supporting functions of the body? And scientists have found, if not a panacea for all ills, then an opportunity to become a little closer to nature, however, thanks not to the blastema, but to stem cells. It turned out that a person has a different principle of regeneration.

For a long time it was known that only two types of our cells can regenerate - blood cells and liver cells. When the embryo of any mammal develops, some of the cells are left out of the specialization process.

This is what stem cells are. They have the ability to replenish blood or dying liver cells. Bone marrow also contains stem cells, which can become muscle tissue, fat, bone, or cartilage, depending on what nutrients are given to them in the laboratory.

Now the scientists had to test experimentally whether there was a chance to “launch” the “instruction” written in the DNA of each of our cells for growing new organs. Experts were convinced that you just need to force the body to “turn on” its ability, and then the process will take care of itself. True, the ability to grow limbs immediately runs into a temporary problem.

What is easily possible for a tiny body is beyond the power of an adult: the volumes and sizes are much larger. We can't do like the newts: form a very small limb and then grow it. For this, amphibians need only a couple of months, a person needs at least 18 years to grow a new leg to normal size, according to the calculation of the English scientist Jeremy Brox...

But scientists have found a lot of work for stem cells. However, first it is necessary to say how and where they are obtained from. Scientists know that the largest number of stem cells is in the pelvic bone marrow, but in any adult they have already lost their original properties. The most promising resource is stem cells derived from umbilical cord blood.

But after giving birth, researchers can only collect 50 to 120 ml of such blood. From each 1 ml, 1 million cells are released, but only 1% of them are progenitor cells. This personal reserve of the body's restorative reserve is extremely small, and therefore priceless. Therefore, stem cells are obtained from the brain (or other tissues) of embryos - abortive material, no matter how sad it is to talk about it.

They can be isolated, placed in tissue culture, where reproduction will begin. These cells can live in culture for more than a year and can be used for any patient. Stem cells can be isolated from cord blood and from the brain of adults (for example, during neurosurgical operations).

And it is possible to isolate from the brain of the recently deceased, since these cells are resistant (compared to other cells of the nervous tissue), they persist when the neurons have already degenerated. Stem cells extracted from other organs, such as the nasopharynx, are not as versatile in use.

Needless to say, this direction is fantastically promising, but has not yet been fully explored. In medicine, it is necessary to measure seven times, and then double-check for ten years to make sure that the panacea does not entail any trouble, for example, an immune shift. Oncologists did not say their weighty “yes” either. Nevertheless, there are already successes, however, only at the level of laboratory developments, experiments on higher animals.

Let's take dentistry as an example. Japanese scientists have developed a treatment system based on genes that are responsible for the growth of fibroblasts - the very tissues that grow around teeth and hold them. They tested their method on a dog that had previously developed a severe form of periodontal disease.

When all the teeth fell out, the affected areas were treated with a substance that included these same genes and agar-agar, an acidic mixture that provides a nutrient medium for cell reproduction. Six weeks later, the dog's fangs erupted.

The same effect was observed in a monkey with teeth hewn to the ground. According to scientists, their method is much cheaper than prosthetics and for the first time allows a huge number of people to return their teeth in the literal sense. Especially when you consider that after 40 years, a tendency to periodontal disease occurs in 80% of the world's population.

In another series of experiments, the tooth chamber was filled with dentin filings (playing the role of an inductor) with the connective tissue of the gums (amphodont) as a reacting material. And the amphodont also turned into dentine. In the near future, English dentists hope to move from successful experiments on mice to further laboratory research. According to conservative estimates, "stem implants" will cost the same as conventional prosthetics in England - from 1500 to 2000 pounds.

Research has shown that people with kidney failure need only 10% of their kidney cells to come back to life to stop being dependent on a dialysis machine.

And research in this direction has been going on for many years. How important it is - not to sew, but to grow anew, not to sit on pills, but to restore a healthy function due to the hidden capabilities of the body.

In particular, a way has been found to grow new pancreatic beta cells that produce insulin, which promises millions of diabetics to get rid of daily injections. And experiments on the possibility of using stem cells in the fight against diabetes are already in the final phase.

Work is also underway to create tools that include regeneration. Ontogeny has developed a growth factor called OP1, which will soon be approved for sale in Europe, the US and Australia. It stimulates the growth of new bone tissue. OP1 will help in the treatment of complex fractures, when two parts of the broken bone are strongly misaligned and therefore cannot heal.

Often in such cases, the limb is amputated. But OP1 stimulates the bone tissue so that it begins to grow and fills the gap between the parts of the broken bone. AT Russian Institute traumatology and orthopedics researchers obtain stem cells from bone marrow. After 4-6 weeks of reproduction in culture, they are transplanted into the joint, where they reconstruct the cartilaginous surfaces.

A few years ago, a group of British geneticists made a sensational announcement: they are starting work on cloning the heart. If the experiment is successful, there will be no need for transplants, which are fraught with tissue rejection. But it is unlikely that wave genetics will be limited to the regeneration of only internal organs, and scientists hope that they will learn to “grow” limbs to patients.

In the field of gynecology, stem cells also have great prospects. Unfortunately, many young women today are doomed to infertility: their ovaries have stopped producing eggs.

Often this means that the pool of cells from which follicles arise has been exhausted. Therefore, it is necessary to look for mechanisms that compensate for them. The first encouraging results in this area have appeared recently.

Scientists are already seeing how it is possible to save people who have been diagnosed with a terrible diagnosis - cirrhosis of the liver. They believe that at some stages of the development of the disease, transplantation of a whole organ can be replaced by the introduction of only stem cells (through the arterial bed, direct punctures, direct transplantation of cells into the liver tissue). Specialists of the Center for Surgery of the Russian Academy of Medical Sciences have begun a pilot study, and the first results are encouraging.

Very interesting preliminary developments are being carried out by Ukrainian scientists in the field of cardiovascular diseases. Already today they have accumulated experimental evidence that the introduction of stem cells to patients with myocardial infarction or severe ischemia is a promising method of treatment.

The first clinical experiments with stem cell transplantation, which began at the University of Pittsburgh in the USA, gave nice results and in severe patients with ischemic or hemorrhagic stroke. After cell therapy, neurological rehabilitation is clearly visible in them.

Unfortunately, the frightening statistics of the number of children with intrauterine brain damage, including those with cerebral palsy, is very well known. It has already been proven that if such children begin stem cell transplantation (or therapy aimed at stimulating them, i.e., at localizing their own, endogenous, cells in the affected area), then after the first year of life, it is often observed that even with the preservation of anatomical children with brain defects have minimal neurological symptoms.

Effectively developed stem cell transplant technologies can completely change our lives. But this is the future, and today this field of knowledge does not even have its own name, only options: “cell therapy”, “stem cell transplantation”, “regeneration medicine”, even “tissue engineering” and “organ engineering”.

But it is already possible to enumerate all the possibilities of this new direction. No wonder they say that the 21st century will pass under the sign of biology, and, perhaps, the experience of regeneration, preserved for millions of years by amphibians and protozoa, will help humanity.

Who just does not attack lizards in nature: and other reptiles more large size, for example, snakes, and rodents, and birds. Lizards try to protect themselves from them in different ways.

Agile lizards have a camouflage color, geckos, on the contrary, are covered with bright warning spots on their backs, similar to eyes. Many lizards, at the sight of an enemy, stand on their hind legs and very quickly and greatly increase in size.

But the most important defense of lizards is it is the ability to throw off the tail. This is not a reflex act, that is, the tail does not fall off by itself, but only when the lizard decides to do so in real danger.

Why does a lizard drop its tail?

It happens in the following way. The tail is, as it were, a continuation of the spine, which, like all vertebrates, consists of vertebrae movably connected by ligaments and muscles.

Tail separation occurs after a very sharp contraction of one muscle group, while the other group clamps the blood vessels. Therefore, when discarding the tail, no blood is released.

A broken piece of the tail either remains in the predator's teeth, or involuntarily contracts on the ground, twitches as a separate creature. And while the stunned predator looks at all this for a fraction of a second, the nimble lizard manages to run away or hide with lightning speed.

From the part where the tail came off a new one begins to grow. But in this place new vertebrae do not appear, but dense cartilage tissue grows. At different types In lizards, the growth of the tail takes from a month to a year.

Each time the tail comes off higher and higher, where the connection is mobile. Until a new tail grows, the lizard is vulnerable and often moves poorly, and aquatic species have difficulty swimming.

Sometimes she returns and eats the discarded tail, as it contains a large amount of accumulated nutrients.

If a very small piece comes off, then the old tail is preserved, and a new one grows nearby. That is, it turns out a lizard with two or even three tails. This is not a mutation, as some people think, but just in such a special way there was a separation. This process is called "autotomy".

Lizards are amazing creatures. Only they, and not all of them, are capable of regenerating lost body parts. The most striking example is the tail. Here's how the lizard throws off its tail, why it does it, and why some lizards have two tails, we'll tell you today.

The main advantage of the lizard

The tail is simply necessary for lizards. The tail is not just an organ, it performs many vital functions for the lizard.

The presence of a tail turns reptiles into the most mysterious and amazing inhabitants planets.

Why do lizards need a tail?

The tail has quite a few uses. The main purpose of the tail is to participate in the movement of the reptile, it serves as a kind of steering wheel that allows the lizard to balance when moving and keep balance relative to the surface on which it moves.

The tail is important for jumping, for example from rock to rock or at height. In addition, aquatic reptiles would not be able to move at all, since it is the tail that allows them to both dive and swim.

Some species of lizards have small, almost invisible Velcro on their tails. They allow the animal to stay on a smooth and slippery surface.

It should be noted that many limb muscles are attached to the tail, which are responsible for movement.

In addition, the tail is a pantry of nutrients for the body of each reptile.

The thickness of the tail indicates how healthy the body of the lizard is.

Tail as a mirror of the soul

Scientists, after conducting research, found out that with the help of the tail, reptiles send certain signs to each other. Certain posture of the tail indicates the age, health, social status or intentions of the animal.

In addition, often, the tail reflects the mood of the lizard.

The tail plays an important role when reptiles go hunting in search of their future partner, and as a consequence, it is used during the mating season.

An individual without a tail is unable to contact its relatives.

A lizard without a tail becomes smaller in size, and it is the size of the lizard that distinguishes it in the hierarchy.

It is for this reason that lizards that have lost their tails fall out of public life and do not have the opportunity to claim the "post" of the leader.

Tailed reptiles, if they notice a disabled person, drive him out of the territory for hunting, and also do not let them near females.

Irreplaceable loss?

An amazing feature of the tail is that it periodically falls off. This happens when the lizard, in an attempt to get rid of the pursuit of a predator, compresses the tail muscles very strongly, and the tail simply falls off.

During an overstrain, the muscles of the tail tighten the blood vessels, so there is not even a trace of blood left in the place where the reptile's tail was.

Some time after the loss, the tail is still moving. This helps to get rid of the pursuit, the predator is distracted by the rustling of the tail (which is provided thanks to small scales) and forgets about the lizard.

Usually, the tail of a lizard grows for a long time, so the lizards become very vulnerable.

Sometimes a situation arises that the lizard already intends to shed its tail during the chase, however, it has not yet fallen off. The tail has already broken, which means that a new organ begins to grow, since the wound healed instantly. After some time, the lizards form two identical tails.

Such animals most often live in the wild.

When talking about health, many people begin to regret that they say that many things need to be abandoned or significantly limited, but they are so used to them. Of course, it’s nice to feel sorry for yourself, but the truth is that it’s impossible to sit on two chairs. In difficult situations, the choice is almost never pleasant, safe and profitable. Therefore, today I want to talk about the principle of the lizard's tail about the inevitability of painful losses in order to preserve key resources in conditions of danger, stress and forced circumstances. The instinct of self-preservation makes us avoid risk, and the survival instinct helps us take risks. How to find a balance?

Conflict of instincts: self-preservation is stronger than reason.

In an ambiguous stressful situation, a conflict often arises between two basic instincts: survival and self-preservation. The instinct of self-preservation is a special form of behavior aimed at protecting one's own life and health.

The instinct of self-preservation- this is an innate form of behavior of living beings in the event of a danger, an action to save oneself from this danger. Realizations of this instinct are such feelings as pain and fear. Pain is usually felt as an abnormal state of the body that needs to be eliminated in some way. Fear makes a living being seek shelter. Animals hide and run away, and a person tries to protect himself from a source of stress.

But what if it can't be done? Unable to run and hide from a stressor that continues to cause damage? Many people resort to various mental defense mechanisms in an attempt to come to terms with their current position. They justify this by saying that “a bad peace is better than a good war”, they are trying to preserve what they have at any cost. But the unfortunate truth is that such a strategy will not work in a really serious situation.The instinct of self-preservation makes us avoid risks.

The instinct makes us shrink and not let go of what we have under any pretext. It's like an organism that blocks fat burning during stress)). Sounds reasonable, but in reality we are like monkeys caught in a banana in this situation. This is how monkeys are caught in India and South Africa. A jar with a narrow neck is tied to a tree. Put a banana in a jar. A monkey passing by sees a banana and, sticking its paw into the jar, grabs it in the wide space of the jar.

Now the monkey is trying to pull the banana out of the jar, but it fails, because the narrow throat does not release the paw squeezing the banana. The monkey sees a catcher approaching her, wants to run away, but cannot, because she can’t get her paw out of the can, which is tied to a tree. Although she clearly does not enjoy meeting the hunter, and the banana and the can are certainly the causes of her troubles, she does not want to part with the banana, which would allow her to remove her paw from the can. She is literally attached to a banana, which has turned from a potential source of pleasure into a source of suffering. We are like such a monkey. There are a lot of “bananas” in our life that we are used to or aspire to, and although they cause us suffering, we cannot part with them. Some of them are all sorts of habits, such as cigarettes, coffee, tranquilizers, alcohol, fantasies, illusions, or other values. By themselves, these things are by no means bad, but in some cases they can be harmful to our health or happiness. And we, realizing this, nevertheless, cannot get rid of them, because we are used to them and consider them “part of ourselves”.

Survival instinct and risk.

The survival instinct is a vital impulse that is directly related to the fear of death. death in this case means everything that is dangerous, that makes us feel weak, sensations that a crisis provokes and to which we respond with this impulse of libido, which evolutionists would call a sense of survival. The survival instinct allows you to overcome the instinct of self-preservation in cases where hiding or avoiding the stressor becomes unprofitable. From a survival point of view, it's better to take risks. A feature of the instinct of risky behavior is that it is manifested by a decrease in the instinct of self-preservation, because. pushes the individual to dangerous behavior that can lead to injury or even death. Risk behavior is also influenced by culture and social conditions. Man has always existed in a situation of the need to display risky behavior, i.e. making a decision, the consequences of which are uncertain and often negative or even deadly. predator threat, natural factors, wars created an almost constant situation of risk. The propensity to risk is a fairly stable characteristic of the individual and is associated with such personality traits as impulsiveness, independence, striving for success, and a tendency to dominate.

Throwing away what is necessary for survival.

A classic biological example comes from the mechanism of action of leptin. This hormone regulates metabolism and helped our ancestors survive in severe conditions of calorie deficiency. Unfortunately, the current theory of calorie counting does not take into account this mechanism. How did the prisoners in the concentration camps, who received from 700 to 800 calories a day, manage to survive? If the theory of calorie counting is correct, then, according to it, they should have died, used up all their stored fat reserves, that is, after a few months.

Suppose that with a daily need of 2,500 calories, a person consumes exactly this number of calories for a long time. If suddenly this number of calories decreases to 2000, then the body begins to compensate for the missing amount due to reserve fat, and, accordingly, weight loss occurs. On the other hand, if the intake of calories has been established at the level of 2000 after the previously received 2500, then the body, under the influence of the survival instinct, will quickly adapt to precisely this level of calories. And then the weight loss will stop. But the body is very smart. The survival instinct will induce him to be even more cautious, and this caution will be directed to the creation of reserves. If they continue to give him only 2000 calories, well, well! He will reduce his energy requirements to 1,700 calories, for example, and save the difference of 300 calories as visceral fat. And here a paradoxical thing happens: although a person eats less (and his body, accordingly, receives fewer calories), he begins to slowly recover, putting fat in the liver and mesentery.

In these cases, the body goes into deficit mode to slow down energy expenditure and get through the tough times. It is known that many animals can even hibernate. Scarcity mode is an adaptation to famine times. The body in deficit mode tries by all means to slow down the expenditure of calories. This is the cessation of fat burning, slowing down physical activity, decreased motivation and performance, suppression of sexual and reproductive function. It's a shutdown thyroid gland and ovaries. Deficiency mode is the activation of eating behavior to search for high-calorie foods, turn off saturation and maximize fat gain.Under conditions of stress, leptin helps us survive by turning off what we can do without: immunity, reproductive system, skeletal system, putting the body into deficiency mode. But leptin does not save on the cardiovascular system, and this is understandable: the cessation of its energy supply will lead to death.

Leptin and the lizard principle.

The hormone leptin teaches us simple wisdom: you need to be able to sacrifice in order to survive. Unwillingness to sacrifice what is important will not give you the opportunity to win in difficult situations. We must be willing to sacrifice our maximalism (all or nothing) for our own salvation. Let's take the lizard as an example. She does not hesitate to leave her tail in the teeth of a predator or in our hands, but she herself is saved. It is critically important to learn how to make a choice.

Any stressful situation involves at least two ways out: the worst is to leave everything as it is and wait for the worst, the best is to sacrifice relatively little, save yourself, your health and win. \ With inadequate personal boundaries, it is problematic to apply the principle of the lizard's tail. Why? If you think that something is an integral part of your personality, then you cannot sacrifice it. And many people have extremely inflated personal boundaries that make them very clumsy.

This is the principle of the lizard: to give away what is important in order to keep what is important. The lizard principle is tail (body part) in exchange for life. Save the vital, irreplaceable from the replaceable, not necessary for survival. To properly understand this metaphor, let me remind you that shedding a tail for a lizard is not so easy. Therefore, before that, she assesses how great the threat to her life is. The process of dropping the tail is completely controlled by the brain, and is not a reflex.

How does this happen?

The tail of a lizard is a spine of several zones interconnected by cartilage, ligaments and muscles. Each zone can be torn. When a threat occurs, the muscles and ligaments in the immediate area are reduced, torn, and the tail is separated. The severed tail continues to shrink and move, thereby diverting attention to itself. And his former mistress at this time runs away from danger.

When a new tail grows in a lizard, the vertebrae at the place of separation are not restored, cartilage is formed in their place. Therefore, each time the gap is higher and higher. The tail of small lizards grows in about a month. For larger ones, this process takes up to one year.

A lizard without a tail is no longer so nimble and fast, it may lose its ability to reproduce, it runs poorly and climbs due to the lack of a “rudder”. Water lizards can no longer swim and are forced to change their way of life. But the main thing is that in many lizards the tail serves to accumulate fat and nutrients, which means that all their energy is concentrated in the tail. Therefore, after its separation, the animal may die from exhaustion. Therefore, often a rescued lizard tries to find its tail and eat it in order to restore lost strength.

Conclusion.

Ask yourself how much do you want to survive? Remember the freedom-loving predators who bite off their own legs when they fall into a trap. I remember an episode from a movie where the leader of a delinquent mafioso offers a choice: bite off his finger with his teeth or he will be shot. The offender failed and was killed. Would you?

The lizard is losing its tail, when it hits a trap or an enemy's teeth. Defensive reaction - this ability is called her.

And the ability to grow a new organ instead of the old one is called regeneration. This is how lizards escape from their enemies (predators, birds).

That is why do not even try to grab the lizard by the tail!

For a lizard, the loss of a tail is absolutely painless, and with its help it maintains its position in space and balance. Unfortunately, the tail grows very slowly.

Regeneration is also characteristic of other animals, but not to the same extent. For example, if a lobster or crab bites off a ray starfish, it can grow back. It is interesting that the bitten off ray can crawl and wriggle for some time.

Why does this happen? Muscles and nerve endings continue to function as long as there is oxygen in the blood.

Such a property is not at all useless. In nature, nothing is done in vain.

A peculiar way of protection is the movement of a severed limb. The predator is confused and cannot understand where his prey is going, and he is forced to stop and think.

This delay is often enough for the lizard to escape. Thus, she can win another day in her life, although this day will pass without a tail.

The strong do not always manage to keep the victory over the dexterous!