Why does a lizard stick out its tongue? Lizard shows tongue

These animals raise many questions: how does a lizard's tail come off? How does a chameleon change its color? How can a flying dragon glide? When we studied the topic “reptiles” as a class, I found answers to some questions, but not all. And I decided to get to know the reptiles better and find out more about them. That's why I chose this topic for the project.

With more than 3,500 species, the lizard suborder is today the largest group of reptiles. Lizards range in size from the 2.5cm gecko to the 3m giant Komodo dragon, appearance and coloration.

Sensitive tongue

To understand what is happening around, lizards stick out their tongues. This way they find out where their relatives, probable prey or enemies are. But the tongue serves the lizard not only for this.

In the world of reptiles, the arboreal chameleon is rightfully considered the most accurate shooter. Its tongue, curled in its mouth, is the same length as its body, or even longer. Having discovered an insect, the chameleon “shoots” its tongue and immediately eats its prey. To intimidate enemies, the Australian giant smooth lizard (blue-tongued skink) sticks out its tongue and waves it threateningly. Geckos wash themselves with their tongue and even rub their eyes with it.

Masters of disguise

Many lizards change color, this is well known. In order to avoid being noticed by both future victims and predators, they disguise themselves as their environment. And first place for the ability to change its color should rightfully be awarded to the chameleon, which does this depending on its mood.

Eggs and hatchlings

Lizards, like snakes, are ovoviviparous. But in most species, the mother lays eggs and immediately leaves. The female leopard gecko lays her eggs in a shallow nest. During the months during which the embryos develop inside the eggs, the soft and sticky shell of the egg will become hard and durable.

The baby green iguana's mother is long gone, but once it emerges from the egg it will be able to fend for itself.

The female North American striped skink (Japanese skink) is one of the few lizards that guards its eggs and cares for its young until they can survive on their own.

Venomtooth

The poisonous serpentine is too slow to chase prey, so it feeds on eggs and newly born animal cubs. It stores excess nutrients in the tail in the form of fat, and thanks to this, it can eat nothing for more than a year.

Marine iguana

The marine iguana, which lives on the Galapagos Islands (they are located almost 1000 kilometers from the coast of South America), is the only lizard that has adapted to life in sea water. For large seaweed - its favorite delicacy - the marine iguana can dive to a depth of 9 meters. Coming out of the cold water, she climbs onto the rocks and basks in the hot sun.

frilled lizard

The Australian frilled lizard spends most of its life in trees. When she has to go down to the ground, she stands up almost vertically on her hind legs, opens the huge collar that frames her head, opens her mouth and runs away with a hiss.

Water Runner

Found in Central and South America, the basilisk can actually run on water. Having developed incredible speed, this lizard manages to take several long steps with its long legs before its body plunges into the water. A sail-like crest runs along the entire body of helmeted basilisks.

Once mistakenly classified as a lizard, the hatteria is actually the only surviving member of a distinct group of ancient reptiles. The New Zealand Maori gave the tuatteria a name that means "bearing thorns on its back."

The hatteria's skull is very durable and resembles that of a crocodile. The hatteria shares its home with seabirds and spends the hottest part of the day there, crawling out of its burrow to hunt at night. Unlike other reptiles, it can lead an active lifestyle at fairly low air temperatures. At the beginning of life, tuataria develop slowly. Their young hatch from eggs after 12-15 months, in this sense, tuataria are champions among reptiles. And they also live a long time - usually more than 100 years. One of the most interesting features of the hatteria is their third eye, located at the top of the brain. It is susceptible to light, although it is covered with skin on top, but, unlike real ones, it does not see anything.

Barbed defense

Toad-shaped, or horned, lizards are small animals with a toad-like head. Their bodies are covered with small spiky spines and very sharp teeth. If a toad lizard is very frightened, it may release streams of blood from the corners of its eyes.

Giant lizard

The weight of the largest lizard - the giant Komodo dragon - reaches 160 kilograms. He hunts large animals - deer and wild boar. Sometimes monitor lizards even attacked people and killed them. Komodo dragons live only on small Indonesian islands.

viviparous

Where did this name come from? The fact is that lizards, like other reptiles, lay an already fertilized egg; it is to some extent protected from adverse environmental influences. But even an egg with a thick shell requires careful handling. It can develop successfully only at a certain temperature and humidity, being protected from mechanical damage. It is not surprising that some reptiles have found a way out in viviparity.

In different species one can find different stages of the transition from actual oviposition to true viviparity. Females of many species lay eggs in which the embryo has already begun to develop. Sometimes the development of the embryo in newly laid eggs reaches such a level that the incubation period of the eggs is significantly reduced and the young hatch soon after the eggs are laid. In some lizards, almost all the development of embryos in eggs occurs in the body of the female, and she no longer lays the eggs themselves, but live young, but still in the egg shell. Newborns immediately destroy these shells and begin to lead an independent life. This phenomenon is called ovoviviparity. Our viviparous lizard belongs to such ovoviviparous species. Viviparity is an adaptation to harsh cold environmental conditions. This is understandable: the cold soil of the northern regions is not very suitable for incubating eggs. The same viviparous lizard lays eggs in the southwest of its range, in the Pyrenees, in a drier and milder climate.

WITHOUT MALES

Lizards have occupied a very important place in scientific research. For example, while studying lizards, scientists discovered the phenomenon of natural parthenogenesis among terrestrial vertebrates. What is parthenogenesis and why was its discovery in lizards revolutionary? Parthenogenesis is reproduction without the participation of males and is a fairly widespread phenomenon in the animal world. There are many known species of animal worms, mollusks, insects, crustaceans and other invertebrates that reproduce normally without the participation of males, and often they do not have a male sex. As for highly organized vertebrates, it was believed for a long time that same-sex reproduction was impossible in them.

HOW THE TAIL COME OFF

Most people's knowledge about lizards is very poor. The most well-known fact is, perhaps, that lizards can throw off their tail when in danger - a very interesting phenomenon called autotomy. In the caudal vertebrae of lizards capable of autotomy, there are non-ossifying layers along which the tail breaks off. The breaking itself occurs due to a sharp contraction of the tail muscles. The discarded tail wriggles intensely for a long time, distracting the predator from the lizard itself, which meanwhile manages to hide. The base of the discarded tail hardly bleeds - the torn vessels are reflexively compressed by the muscles. And soon a fairly rapid process of growing a new tail begins, almost indistinguishable from the old one, and the vertebrae are not restored, but are replaced by a cartilaginous rod, which is why a new separation is possible only higher than the previous one. A restored (regenerated) tail is usually easily recognized by its slightly different scales, and often also by the color of the regenerated part. By the way, autotomy is not a voluntary, but a reflex act: if you carefully glue a living lizard by the tail, it will not be able to throw away part of the tail and thereby free itself. However, not all lizards can cast their tails. Those of them whose tail plays a special role (an oar, an organ of attachment or protection) are deprived of both the ability of autotomy and regeneration.

They are trying to instill the abilities of a lizard in humans

Some amphibians and reptiles can regrow severed limbs, quickly and without a trace heal deep wounds, and restore damaged organs, but the human body is not capable of doing this. British scientists will have to find out whether it is possible to give him the same abilities. Among amphibians and reptiles, there are many creatures that have the ability to “repair” themselves. Lizards, when attacked by a predator, can get rid of their tail, and then grow it back in 3-4 months. Salamanders are able to regrow damaged limbs, restore parts of organs and even the brain.

Enrique Amaya, a tissue scientist at the University of Manchester, explains his experiment: “We cut the tadpole. It was a large wound, equivalent to what a 20-year-old man would get from falling off a motorcycle at 100 km/h. Within an hour and a half it was completely healed.” However, the scientist notes, grown frogs lose this ability.

Recently, the British charity Healing Foundation donated £10 million to scientists at the University of Manchester to help them unravel the phenomenon of organ and tissue regeneration. Researchers must identify the genes responsible for recovery and figure out how they control such a complex process, and then try to instill these abilities in humans. This work began a long time ago: Professor Amaya identified 10 thousand genes in the frog that are responsible for regeneration, some of which were similar to human ones. “Don't think this goal is unrealistic,” Amaya says. - The potential for regeneration is in each of us. Human fetuses in the womb, if operated upon before the sixth month of pregnancy, heal wounds without leaving scars, but this ability is subsequently lost. Humans and amphibians share 85% of their genes, and it is very likely that the adult human has latent genes for scar-free healing.” The salamander regenerates organs thanks to the blastema, a universal group of cells that have the ability to transform into any tissue. Mammals, whose brain and body structures are much more complex, have lost the ability to regenerate. Stem cells, from which all organs are “built,” almost immediately after birth lose their universalism and acquire specialization. Research from the University of Manchester will explore whether the salamander's regeneration mechanism can be applied to an adult frog, then try to transfer the method to mice and then to humans. Scientists hope in the future to develop drugs or gene therapy techniques that can restore human limbs that are damaged or completely lost in accidents. “Already in this generation, a new method for restoring human limbs, organs and skin will become possible,” promises Professor Amaya. "It's a question of money, resources and research," says Gus McGruther, who leads research into plastic and reconstructive surgery at the University of Manchester. But this will certainly happen." The problem that doctors must solve when developing a new method is how to avoid uncontrolled cell division during regeneration, which leads to cancer.

On weekends, I went to the dacha with my parents. There I found two places where there are a lot of lizards, and I took into account the fact that they bask in the sun in the spring. The first place was behind the house, there was firewood there, and the second was in an old stump. There were about 7-8 lizards in the stump. Where the firewood lay, the lizards were very fast, I could not keep up with their agility. I was just trying to catch the lizard when it ran away. They reacted to my shadow and felt the approach of my hands. But I was able to outwit them: I took a thin stick, pressed the lizard, and then quickly grabbed it with my hands near the head, because I knew that it could bite. So I caught five lizards. They were all from a stump. I couldn't catch a single one in the firewood. They were very fast, and their color blended with the wood. These were tree lizards. One of the lizards' tail came off, it twisted and flew to the side. In the place where the tail was, a depression formed, there was no blood, and at the edge of the tail there was a protrusion, also without blood. But I was still able to catch this lizard without a tail. I collected the lizards in a jar, in the lid of which I made holes so that air could flow in. I also saw two lizards fighting. The larger lizard delivered three bites and the smaller lizard began to bleed. I didn’t see the end of the battle; they ran away, but then I found the head of a lizard near a tree stump. I don't know for sure if it was the same lizard.

I left two lizards in the jar to observe them, but I released the rest. After ten days of living in the jar, the tailless lizard developed a small tail. Both lizards eat grass, live quietly, calmly, and do not fight. They are inactive in the bank. As soon as the lizard develops a full-fledged tail, I will release them. I'm interested to know how long it will take for this to happen.

The most interesting and unusual organ of a snake is its tongue. Its unusual shape has always attracted attention and has been actively discussed. In our article we will tell you why a reptile needs a forked tongue tip, and why it constantly sticks it out.

What is the tongue of a snake called?

Many people call this part of the snake the “deadly sting” and believe that if the snake sticks it out, then it is definitely poisonous and plans to sting, as a result of which the poison will penetrate the human blood. Unfortunately, because of this misconception, people often unknowingly kill animals that do no harm at all. But in fact, the long tongue of a reptile, at the end of which there is a fork, is one of its most important organs.

Important! If you meet a snake on your way, you need to stop and freeze, even if it sticks out its tongue. Thanks to its olfactory organs, the animal will understand that there is no food nearby, and besides, it may be in danger from humans, and will crawl away.

A snake's tongue is not a sting at all, and there is no poison in it. This is the organ of smell. It forms an entire system together with Jacobson's organ and is a thin chemical analyzer, which has 2 outlets located on the upper palate. For protruding the forked tip there is a semicircular notch in the upper jaw.

After the tongue is outside, the animal can twitch it for a couple of seconds, touch objects that are nearby with the tip, and then immediately pull it inside. After this, the tips end up in the opening of Jacobson's organ. It is here that the snake can obtain information about what substances and objects were outside.

Interestingly, the tongue itself is not located in the oral cavity - it is located lower, in an additional hole.

Why is the snake's tongue forked?

Its main purpose is the sense of smell. And the fact that it is forked at the end allows the animal to receive information simultaneously from 2 different places. The tips of this organ are able to “smell” a smell that is located at a distance of about 2 heads.

Thanks to the information received from the bifurcated organ, the reptile can understand in which direction it should move in order to find food. This is very convenient, since in most cases the prey is hidden from view and is quite difficult to notice.
In addition, thanks to the forked tongue, these animals can find their brothers.

Why do snakes stick out their tongues?

By protruding it from the intermaxillary opening, the reptile provides itself with orientation in space. This is perhaps one of the most important organs, since such animals do not have good eyesight, and they also do not have an eardrum. Thanks to their forked tongue, snakes can always find out what is nearby, where to move in search of food, and when to urgently crawl away because an enemy is nearby.

Sometimes I go out to wander around in the spring without any purpose.
Your roads and desert beckon into the distance.
I'll leave the house, say goodbye to the hateful mountain,
All the lands before you are wretched, desert.

Seitnazar Seydi

Monitor lizard family ( Varanidae) has 35 species. The word “monitor lizard” itself is of Arabic origin. Originally this was the name given to the species common in Africa. Nile monitor lizard(Varanus niloticus), and then - all the other lizards of this family. Monitor lizards are large and medium-sized lizards, mostly active predators. True, sometimes they can also eat carrion, and the diet of some tropical species includes fruits.

Monitor lizards are distributed exclusively in the Old World, with the vast majority of species found in Australia and on the island of New Guinea. In addition, monitor lizards live in tropical and subtropical areas of Asia and Africa, including some islands. Different species of these lizards inhabit different habitats - from mangrove swamps to hot and dry deserts. As a rule, they climb trees and rocks well, swim well and willingly go into the water.

On the territory of the former USSR, the only representative of the family is found - gray monitor lizard(Varanus griseus). It is distributed in Southern Kazakhstan and the republics of Central Asia - from the eastern coast of the Caspian Sea to the Tien Shan, and in the north to Ustyurt and the Aral Sea. Along the Syrdarya valley, the monitor lizard penetrates into the Fergana Valley, and through the Amu Darya valley into southwestern Tajikistan. In addition, the gray monitor lizard is found in northern Africa, southwest Asia, Iran and Afghanistan.

This lizard inhabits various types of deserts and semi-deserts - sandy, clayey, loess, rocky; found on coastal cliffs, in tugai forests, and sometimes enters cultivated lands.

Together with its tail, the gray monitor lizard can reach a length of 150 cm and weigh up to 3.5 kg. Its body is massive, strong legs with sharp, slightly curved claws on its toes. The very strong and long tail of the gray monitor lizard is not flattened laterally, like other monitor lizards, but rounded in cross section.

The color of the monitor's scales is in harmony with the surrounding background: it is grayish-brown with a reddish tint. Dark dots and spots are scattered throughout the body, and dark stripes run across the back and tail at almost equal distances from each other.

The nostrils of the gray monitor lizard are curved in the shape of the letter “L” and open near the eyes. This makes it easier for the animal to inspect the burrows - the nasal passages are not clogged with sand. The jaws of this lizard are strong and long, and the teeth, designed to hold prey, are sharp and slightly curved back. Over the course of life, they are gradually erased and replaced by new ones.

Sometimes the monitor lizard is called a land crocodile - for its size, strength and gluttony. When in danger, it takes a threatening pose: it opens its mouth wide, sticks out its tongue, hisses loudly and lashes its tail left and right. At the same time, his body swells and becomes wide and flat. If you get too close to a threatening monitor lizard, it may bite. Holding a resisting monitor lizard in your hands is very difficult and dangerous: it whips with its tail, and the animal’s large teeth can seriously injure it.

The diet of young lizards is dominated by large insects, mainly locusts. Adult monitor lizards eat various rodents (gerbils, mice, gophers), and do not disdain young hedgehogs, lizards, small turtles, frogs and toads.

The monitor lizard simply licks small prey with its tongue. It grabs eggs, chicks and other sedentary animals, squeezes them tightly with its jaws and swallows them. The monitor lizard can pursue large prey for some time, and having caught it, shakes it and presses it to the ground, after which it swallows it.

There are known cases of monitor lizards eating large vipers and cobras. When hunting them, he first tires the snake with false attacks and approaches from different sides - just as a mongoose does. Then, in a precise throw, he grabs the snake behind the head, shakes it, breaking vertebrae, hits it on the ground or stones and holds it, clenching his jaws, until it dies.

When a monitor lizard bites, saliva enters the victim's wound, apparently having poisonous properties. In humans, it causes fever, headache and nausea, and small animals (rats, sparrows) when injected intramuscularly with monitor lizard saliva stop moving for a while. Monitor lizards always swallow their prey whole, just like snakes do.

The monitor lizard usually receives water along with food, but on occasion it willingly drinks, bathes and catches freshwater crabs. The monitor lizard drinks in a unique way - it dips its head over the eyes, draws water into its mouth and, raising its snout up, swallows.

The monitor lizard is active during the day. He walks around his site every day and in search of food can go more than a kilometer away from the shelter. Usually it moves slowly, at short distances, escaping from pursuit, it can develop quite a decent speed.

A monitor lizard's hole is a refuge with a certain microclimate. He digs it himself or uses the hole of some rodent, expanding and deepening it up to 4 m. Here he rests, hides from enemies, and also spends the winter months in hibernation, plugging the entrance with an earthen plug.

Adult monitor lizards have practically no enemies other than humans. But young lizards often become victims of large birds of prey (vultures, snake eagles) and honey badgers. They are also attacked by their relatives.

The mating behavior of gray monitor lizards is accompanied by a variety of demonstrative and ritual poses. Scars can sometimes be found on the body of males - the results of skirmishes.

Female gray monitor lizards usually begin breeding at the age of 3 years. In June–July, they dig deep winding holes and there lay up to 23 eggs in wet sand. Young monitor lizards are born in late August–September and soon leave for the winter. Their coloring is very bright, thanks to almost black stripes on the body and tail. It fades with age. After wintering, lizards appear on the surface in late March–April.

The gray monitor lizard has a beautiful skin, which was valued as a durable and beautiful material for making bags and women's shoes. In the 20–30s. In our century, these lizards were caught in large numbers, which led to a sharp reduction in their populations in Turkmenistan and Southern Kyzylkum. The monitor lizard population in these areas recovered many years later.

However, even now the gray monitor lizard remains a rare species in the territory of the former USSR. It is gradually disappearing from the Fergana Valley and the Hungry Steppe, and its numbers are decreasing in other places. The main reasons for this are anthropogenic changes in habitats and the disappearance of food, the construction of new roads and intense traffic on them.

Few people like to look at snakes, since this sight is very unpleasant. But everyone has probably noticed how this reptile often sticks out its tongue.

By nature, snakes have not only very poor eyesight, but also myopia. Also, these reptiles do not have eardrums at all. This is how nature created them, but they can still hear, but rather poorly.

But their body can catch every little rustle. A well-developed sense of smell plays a very important role and makes it possible to receive information about the movement of the enemy. All this is thanks to the snake’s tongue, which can easily and quickly pick up even the slightest trace of scent from the air. Also, the tongue plays the role of an organ of touch, therefore, thanks to the tongue, snakes move very well around the terrain.

A snake can easily find out who or what is nearby, and it does this with its forked tongue, which it pulls out and recognizes even the slightest odors. In the snake’s oral cavity there is a special Jacobson organ, to which the tongue delivers the information it has caught, and it, in turn, analyzes the substances received.

After all this, the analyzed information enters the reptile’s brain. Since the above process occurs instantly, the snake will very soon find out who is in its neighborhood. Sensing danger, the snake begins to attack.

Males also use their tongue to court females. If the female does not respond to his protruding tongue, the male seeks attention elsewhere.