Monitor lizards. Gray monitor lizard Can a monitor lizard exist without a tail?

The monitor lizard is the largest of all lizards living on earth. They are not inferior in size to crocodiles, although they are not related to them family ties. It is also one of the most ancient animals. Systematically, monitor lizards stand closer to snakes. These reptiles separate family monitor lizards, including more than 70 species.

So, what does a monitor lizard look like?

All types of these large lizards have a medium or large body size - about 0.5-1 m. The largest is the Komodo dragon, which is also called the Komodo dragon. Its length is about 3 m, and it weighs 140 kg! Well, you must agree, isn’t it a dragon?

The Emerald Monitor (Varanus prasinus) is the most striking species. This monitor lizard lives in tropical forests and its green color serves as a camouflage function.

Large size and well-developed muscles distinguish large monitor lizards from other individuals. They have tenacious and strong paws, middle part the abdomen is somewhat expanded, a long, fleshy, whip-shaped tail. Many monitor lizards have a tail the same length as their body.

Unlike a real lizard, in moments of danger, monitor lizards do not drop their tail, but they whip it perfectly from side to side. The monitor's muzzle is rounded on the nose, but its general features are more suitable to describe a snake than a lizard. True, this lizard has round pupils, while the snake does not.

The reptile's body is covered with large, rounded scales, and each finger has a long, sharp claw. At the very tip of the tongue there is a fork, thanks to which the monitor lizard smells odors that are very far away. The color of monitor lizards is not variegated, with a predominance of gray, sand, black, and brown tones. But some young individuals have a spotted and striped pattern.

Where do monitor lizards live?

Monitor lizards are amateurs warm climate, therefore their habitats are located within tropical zone. The largest species diversity of these lizards is found in Australia and the surrounding islands.

What does a monitor lizard eat?

The monitor lizard is an active predator, not too picky about food. They feed on smaller reptiles (even poisonous snakes), young turtles, and insects. A special delicacy for monitor lizards are crocodiles, bird eggs, and snake eggs, so regularly visiting places of possible clutches is like a hobby for them. The reptile can swallow all prey whole, or bite off pieces with its mouth.

Reproduction of monitor lizards

Monitor lizards, like most snakes, lay eggs. The mating season occurs at the beginning of spring. The female lays 15-20 eggs. Since the animal lives in a warm climate, brooding does not occur. However, as well as the responsible upbringing of offspring.

Enemies of monitor lizards in nature

Thanks to large sizes The monitor lizards did not make any enemies. Only young individuals are vulnerable, which can even be eaten by their own relatives. As a defense, the lizard hits the attacker with its massive tail, hisses, opens its mouth and bites very painfully.

Rare species

Some species of monitor lizards are listed in the National Red Book, and the Komodo dragon is listed in the International Red Book.

Gray monitor lizard (Varanus griseus) – a real giant among lizards Central Asia. Its habitat is extremely wide and includes North Africa, Southwest Asia east to Pakistan, Turkmenistan, Uzbekistan, Southern Kazakhstan, Kyrgyzstan, Azerbaijan. It is found in various types deserts and semi-deserts on fixed and semi-fixed sands, as well as on rocky foothills and along river cliffs. The gray monitor lizard is an exceptionally heat-loving animal, and it entered Kazakhstan from the south; it is not found in the deserts east of the Karatau ridge. Usually he avoids people, however known cases its entry into cultivated lands and populated areas.

The length of the gray monitor lizard can reach 1.5 meters, of which the tail accounts for about 90 cm; the lizard weighs about 3.5 kg. Due to its impressive size, it is sometimes even called the desert crocodile. The body and tail of the lizard are powerful, the head is elongated. The color of the upper side of the body of an adult animal is sandy-yellow with a pattern of numerous dark spots and dots. The juvenile is easily distinguished by its light gray skin color. The body and tail are surrounded by dark transverse stripes, on the back their number varies from 5 to 8, on the tail from 16 to 19. 2-3 brown stripes run along the upper side of the neck.

Gray monitor lizard: features of the lizard

The position of the monitor lizard in the evolutionary series is not entirely clear, but most zoologists believe that snakes evolved from monitor lizards. Indeed, monitor lizards living today have a lot in common with snakes: the brain of both is enclosed in a bone capsule, the neck is significantly elongated, the tongue is long and deeply forked, like that of snakes. In addition, similar signs were noted in the structure of the heart and the microstructure of the stomach. Some of the habits of monitor lizards resemble those of a snake. Thanks to the extensibility of the neck and throat, the monitor lizard can swallow large prey and eats by moving its mouth towards the victim. Particularly noteworthy is the fact that the saliva of the gray monitor lizard is poisonous, and its bite causes the same processes in the human body as snake venom.

The monitor lizard is a fast and agile lizard. It can briefly reach speeds of up to 20 km/h, makes sudden and sharp turns, and climbs trees quite well, where it usually climbs for the eggs and chicks of birds nesting there. Despite the fact that the monitor lizard is a desert animal, it swims well, in captivity willingly drinks water and loves to swim.

The monitor lizard is unusually tenacious - it is difficult to put it to sleep in ether vapor. Moreover, he for a long time may be underwater. In moments of danger, it strives to hide in a hole, and if this is impossible, it presses itself to the ground and lies motionless.

The threat pose performed by the monitor lizard is very impressive - it rises on its limbs, inflates its throat, opens its mouth wide, sticks out its tongue and begins to swing its tail from side to side, while loudly hissing, periodically drawing air into its lungs and releasing it forcefully.

The gray monitor lizard is characterized by one exceptional phenomenon. Special studies have shown that he is able to tolerate huge doses of cobra and viper venom with absolutely no harm to himself. His behavior after the bite does not change and there are no signs of poisoning. There is no swelling or hemorrhage at the site of the bite, and soon its traces disappear completely. As scientists have established, the monitor lizard can tolerate up to 200 doses of viper venom that are lethal to humans and up to 4,000 doses of cobra venom. This feature gives him the opportunity to hunt large poisonous snakes. In Turkmenistan, for example, it eats cobras and vipers more than a meter in length.

In nature, the gray monitor lizard lives 7-8 years. The long-lived monitor lizard is also known - in Leningrad Zoo The gray monitor lizard was kept for 17 years.

How does the gray monitor lizard live in nature?

Monitor lizards lead a diurnal lifestyle, although in extreme heat they prefer to sit out in shelters, which serve as burrows of rodents and turtles - they expand and deepen them if necessary. Sometimes in sandy deserts Monitor lizards dig holes on their own.

In spring, the monitor lizard is very cautious and inactive. Before appearing on the surface, it slowly, barely noticeably sticks its head out onto long neck from the hole, being in a tense position, listens for a long time and looks closely at everything around him. By mid-May, the monitor lizard's activity increases; it begins to make long treks from one dune to another. Its traces are often found on the roads that it crosses in search of food. At this time, he leads a wandering lifestyle and spends the night where it gets dark. Some zoologists believe that the monitor lizard makes treks several kilometers long.

Monitor lizards overwinter alone or several individuals in one burrow. In Turkmenistan, for example, the monitor lizard is awake only 3-4 months a year, then most individuals plunge into summer hibernation, which turns into winter.

The monitor lizard's diet includes gophers, gerbils, jerboas, and mice. It eats not only freshly caught prey, but also rodents caught in a trap, and often ends up in it itself. in spring and early summer readily feasts on young turtles whose shells have not yet strengthened. Does not pass by birds nesting on the ground and their eggs. He does not disdain invertebrates either. Particularly hungry individuals swallow prey instantly. To satiate a monitor lizard, two gerbils are enough. Sometimes young hares, hedgehogs and even large snakes– vipers, snakes and Central Asian cobras. The monitor lizard kills almost all types of prey by vigorously shaking and clenching its jaws with sharp teeth.

Having had enough, the gray monitor lizard rests. The resting places of the monitor lizard are difficult to confuse with anything else. It lies pressed tightly against the substrate, where imprints of regularly spaced rows of ribbed scales remain. When resting, the forelimbs are pulled under the body, and the elbows are set aside.

Monitor lizards become sexually mature approximately in the third year of life. IN mating season, which falls in April-May, fights often occur between males for the right to own a female. With their claws and sharp conical teeth, lizards attack each other deep wounds. In June and early July, the female lays from 6 to 23 eggs, which she guards for several weeks. At the end of August - September, a new generation of monitor lizards is born, and often they immediately go into hibernation.

Keeping a gray monitor lizard at home

Gray monitor lizards are very rarely kept at home. It is difficult to care for them, in addition, they are considered difficult to tame lizards, and only young individuals can get used to a person over time and even let him get close.

If you decide to purchase such exotic pet, then to maintain it you will need a spacious horizontal terrarium (the minimum housing dimensions for a gray monitor lizard are 220x150x60 cm). Both for ventilation side walls The terrarium should be made of metal mesh. During the day, the temperature in the terrarium should be maintained at 28-30°C, and at night – 22-24°C. It is necessary to equip a place in the terrarium where the lizard could warm up - at the warming up point the temperature should be 38-39°C. To maintain the required For an exotic pet, an incandescent lamp connected using a thermostat is placed in the terrarium. In addition, a fluorescent lamp with UV radiation must be installed in the monitor's home. Humidity levels should be maintained at 30-35%. Sand or a mixture of sand and pebbles is suitable as soil, the level of which should be at least 10 cm. The monitor lizard will also need shelters where he can rest, and a pond so that he can quench his thirst and swim.

Conservation status

Once upon a time, the gray monitor lizard was a common and even numerous lizard. It was mined for its beautiful and durable leather, which was used for sewing women's shoes, as well as for the manufacture of wallets, bags and belts. As a result of a widespread decline in numbers, the gray monitor lizard was among the first contenders for the pages of the Red Book. Now it is listed in the IUCN Red Book and the Red Books of Kazakhstan, Uzbekistan, Turkmenistan and Kyrgyzstan, where it is classified as a species of the second category. This means that its numbers are still relatively high, but are declining catastrophically, and in the near future the animal may be on the verge of extinction.

IN natural conditions The monitor lizard has few enemies, but it suffers greatly from humans. People don’t like him and are afraid of him; unjustified cruelty is shown everywhere towards the monitor lizard. Rumors about this large lizard spread like lightning, and people cannot be convinced. There is a belief that a person who meets a monitor lizard will not have children, or some kind of misfortune will happen. Because of these prejudices, it is destroyed much more often than snakes. Many monitor lizards also die on the roads under the wheels of cars. The development of deserts and plowing of lands pushes him deeper into the desert - only here he is in relative safety. Perhaps, like no other lizard, the monitor lizard needs protection and protection.

Monitor lizards are the largest lizards in the world. In size, some of them are not inferior to crocodiles, although they are not related to them. Systematically, monitor lizards are closer to snakes than other lizards. These reptiles are classified into a separate family of monitor lizards, which includes 70 species.

Gray monitor lizard (Varanus griseus).

All types of monitor lizards are medium or large in size, the smallest of them, the short-tailed monitor lizard, reaches a length of only 20 cm, but most of these reptiles have a length of 0.5-1 m. The most large monitor lizard- Komodo dragon (Komodo dragon, Komodo dragon) reaches a length of 3 m and weighs up to 140 kg! Exactly gigantic size This lizard prompted people to call this species a dragon. In addition to their large size, monitor lizards differ from other lizards in their well-developed muscles, their paws are not only tenacious, but also strong, their stomach is widened in the middle part, their tail is muscular, whip-shaped and very long. Most monitor lizards have a tail that is as long as their body. Unlike real lizards, monitor lizards cannot throw their tail away in case of danger, but they can whip it from side to side. The muzzle of monitor lizards is bluntly rounded, but its features are more reminiscent of snakes than lizards. True, unlike snakes, monitor lizards have round eye pupils. The scales on the body are relatively large, rounded, the fingers end in long claws. The tongue at the end is forked like a snake’s, with its help monitor lizards can smell odors at a great distance (this is also a typical snake sign). In addition, the skin on the neck of many species can become very swollen. The coloring of monitor lizards is often dim, with gray, sand, black, and brown tones predominating. Many monitor lizards, especially young ones, have spotted and striped colors.

The Emerald Monitor (Varanus prasinus) is the most striking species. This monitor lizard lives in tropical forests and its green color serves as a camouflage function.

Monitor lizards - residents warm countries, almost nowhere does their range extend beyond the tropics and only the gray monitor lizard in the north of its range lives in temperate zone(in Central Asia). Monitor lizards have reached the greatest species diversity in Australia and on the adjacent islands; these animals are also found in South and Central Asia and Africa. They do not live in the New World. The ranges of most species are extensive, but the Komodo dragon lives only on the Indonesian island of Komodo. This is the rarest and smallest species.

The habitats of monitor lizards are varied; according to their ecological preferences, they can be divided into two groups. Some monitor lizards prefer arid desert areas; they are found in dry bushes, woodlands, savannas, semi-deserts and real quicksand. Other species prefer to stay close to water; they live on the banks of reservoirs in tropical forests. Finally, there are monitor lizards that prefer arboreal vegetation and spend most of their time in trees. However, monitor lizards of other groups are also excellent climbers.

Monitor lizards are active all year round and only the gray monitor lizard in the north of its range hibernates in the winter. Burrows serve as shelter for him, which he seals with an earthen plug for the winter. Other species also dig burrows and spend the night in them. The monitor lizard's burrow is up to 2-2.5 long, and a large Komodo dragon is up to 5 m long! A person can freely climb into such a hole. Monitor lizards are sedentary animals, but they do not adhere to strict boundaries of their territories. Most of the time they are in active search walking around during the day large territory. The movements of monitor lizards are not similar to the movements of nimble real lizards. When walking, they strongly bend their spine and thus resemble crocodiles. However, the sprawling movement is just an illusion of clumsiness; if necessary, monitor lizards can run quickly, climb the branches of trees and bushes, most species are good swimmers.

The mottled monitor lizard (Varanus varius) reaches a length of 2 m and is famous for its ability to climb trees.

Monitor lizards live alone and have a quarrelsome character. Having met at the prey, they immediately enter into a fight. Monitor lizards threaten their opponent with a loud hiss, strongly inflate their belly and lash with their tail. In large species, the blow of the thin but strong tail is like the blow of a whip; it is very sensitive even for humans. Komodo dragons are more relaxed towards relatives of equal size (smaller ones are driven away); sometimes they can share a meal with large prey.

Monitor lizards are active predators. They are not picky about food and will catch almost any animal of suitable size. Depending on the place of residence of a particular species, their prey includes small lizards, snakes (including poisonous ones), young turtles, small mammals (gerbils, hedgehogs, platypuses), and insects. Monitor lizards readily feast on the eggs of crocodiles, birds, turtles, and snakes and regularly check the sites of possible clutches. Monitor lizards search for their prey in two ways: they look for prey while walking around the territory and chase it at a run (mobile, but not too frisky species) or find it by smell (sedentary animals, eggs, carrion). Monitor lizards sense odors from a great distance and accurately determine their source, constantly sticking out their tongue and sniffing the air with it. This search method is not typical for real lizards, but is typical for snakes. Monitor lizards either swallow their prey whole or tear off pieces with their mouths, holding them with their front paws.

The Komodo dragon (Varanus komodoensis) has a thick, inflexible tail that is not used for defense.

Due to their large size, Komodo dragons eat special foods. The basis of their diet is carrion, primarily the corpses of large animals - wild pigs and deer. However, carrion in nature is a “scarce” product. In this regard, Komodo dragons have developed tolerance towards their relatives when eating prey and... the ability to kill their prey. Of course, it’s difficult for a heavy monitor lizard to catch up with a fast-footed deer, but he doesn’t have to catch it, just bite him, and in a couple of days the table is ready. Even a light bite from the Komodo dragon is fatal, which has given rise to talk about the poisonousness of this species. However, these monitor lizards do not have real poison, but they do have a unique substitute. Saliva komodo dragons very viscous and they reproduce in it pathogenic bacteria, their food is small pieces of food stuck between the monitor lizard’s teeth. The owner of the bacteriological weapon himself does not suffer at all from such flagrant unsanitary conditions in his mouth, but when bitten, the bacteria enter the victim’s wound and cause blood poisoning. A deer or pig weakens and dies after a few days, and the monitor lizard finds the victim by smell.

The ring-tailed monitor lizard (Varanus acanthurus) is distinguished by its bright spotted color.

Monitor lizards breed once a year. The breeding season may vary depending on where the monitor lizard lives; in the tropics it coincides with the beginning of the rainy season. Monitor lizards lay from 7 to 60 eggs in burrows, hollows, anthills and termite mounds. The size of the eggs varies from 2 cm in small species to 10 cm in length in the Komodo dragon (such an egg weighs 200 g). The eggs are covered with a soft parchment shell, the incubation period is unusually long - 9-10 months! Parents do not take care of their offspring; young monitor lizards are completely independent after hatching. Medium-sized species (for example, gray monitor lizards) reach sexual maturity by 3 years.

Due to their large size, monitor lizards have few enemies. Small species and young individuals are the most vulnerable; they can even suffer from their own relatives; cases of cannibalism are known among these reptiles. Large snakes can attack monitor lizards, birds of prey, crocodiles. In defense, these animals hit the attacker with their tail, hiss, open their mouths and bite painfully.

The Salvador monitor lizard (Varanus salvadorii) is called the crocodile monitor by the British because of the resemblance of this large lizard to crocodiles.

Monitor lizards also suffer greatly from hunting. In some places they are hunted for meat and eggs collected. But most often monitor lizards are killed for their skin. The skin of these animals is strong, with a beautiful pattern and pleasant texture; it is considered an expensive raw material and is used to make exclusive shoes, bags and other accessories. Now some species of monitor lizards are listed in the national Red Books (gray monitor lizard), and the Komodo monitor lizard is included in the International Red Book. These reptiles pose no danger to humans. As an exception, there are a few known cases of Komodo dragons attacking people, but these can be explained by the small size of the victim (most of the victims were teenagers). Obviously, monitor lizards confuse a short person with their usual prey. Now a reserve has been organized to protect Komodo dragons, tourist access to the habitats of these animals is limited and accidents have become a thing of the past. In captivity, most large species of monitor lizards do not take root well, so they are rarely seen in zoos.

1. Why do the lungs of reptiles have a cellular structure? What effect is achieved by the cellular structure of the lungs in reptiles compared to simple lungs amphibians?

Reptiles have completely switched to terrestrial existence. Their skin does not take part in breathing; only the lungs participate in this process. Their cellular structure increases the surface area, due to which oxygen is absorbed more efficiently.

2. Why is the outside of reptile skin covered with horny scales and scutes?

Answer: This coating serves as protection against mechanical damage and environmental temperature changes.

3. Remember the structural features of amphibian eggs. How are reptile eggs different from them?

Amphibian eggs are eggs laid in water. In reptiles, eggs are covered with a leathery shell or calcareous shell, and they are laid on land.

4. Distribute the listed units into the appropriate classes.

Classes:
A. Amphibians
B. Reptiles

Squads:
1. Scaly
2. Turtles
3. Tailed
4. Legless
5. Crocodiles
6. Beakheads
7. Tailless

Answer:
A. 3, 4, 7
B. 1, 2, 5, 6.

5. Look at Figure 106 in the textbook (p. 124). Guess where the following animals might live:

Chameleon - on trees (mainland, islands)
Roundhead - on the ground (South-Eastern Europe, Asia)
Aaran gray - desert sands (Central Asia)
Iguana - wet tropical forests(Central and South America).

6. What happens if a lizard damages the tip of its tongue?

Answer: The tip of the tongue performs the functions of touch, smell, taste; if it is damaged, the lizard will lose these functions.

7. Read carefully the descriptions of monitor lizards. It is known that some lizards can survive by throwing away their tail in a moment of danger. Can a monitor lizard exist without a tail? Why?

Answer: No, he can’t do it completely without a tail. The monitor lizard casts only the tip of its tail, which then grows back. Thus, the monitor lizard gets rid of the predator.

8. Read the descriptions of snakes carefully. How do snakes compensate for poor development of vision and hearing?

Snakes have a tongue, which serves as an organ of touch, smell and taste. By sticking it out and removing it, the snake receives information about odors in the air, and if it touches surrounding objects, then about their surface. In addition, snakes can sense an object at a distance by its movement, sensing the sound wave emanating from it.

9. What snakes swallow live prey?

Answer: Python, boa constrictor, anaconda, water snake, yellow-bellied snake and other non-venomous snakes.

10. What structural features provide snakes with the ability to swallow prey whose thickness exceeds the diameter of their body?

Answer: This is facilitated by movable jaws. The lower jaw is connected to the bones of the skull movably, moves forward and goes back. Its halves are connected at the chin by a flexible ligament and are able to move apart from each other to the sides.

11. What is crawling? How is it formed?

Answer: The crawl is the snake's outer covering (skin), which it sheds when molting.