Varanas are dangerous. Dragons of Komodo Island - how a strategy in hunting helps to win a deadly fight. Are monitor lizards dangerous?

Indonesian Komodo island is interesting not only for its nature, but also for its animals: among the tropical jungle of this island, real " dragons»…

Such " the Dragon"reaches a length of 4-5 meters, its weight ranges from 150 to 200 kilograms. These are the largest individuals. The Indonesians themselves call the "dragon" " land crocodile».

komodo dragon is a diurnal animal, it does not hunt at night. The monitor lizard is omnivorous, it can easily eat a gecko, bird eggs, a snake, catch a gaping bird. Local residents say that the monitor lizard drags sheep, attacks buffalo and wild pigs. Cases are known when komodo dragon attacked a victim weighing up to 750 kilograms. In order to eat such a huge animal, the “dragon” bit the tendons, thereby immobilizing the victim, and then chopped the unfortunate creature with its iron jaws. Once a monitor lizard swallowed a furiously squealing dog...


Here on Komodo island, nature dictates its own rules, dividing the year into dry and wet seasons. In the dry season, the monitor lizard has to adhere to the "fast", but in the rainy season, the "dragon" does not deny itself anything. komodo dragon does not tolerate heat well, his body does not have sweat glands. And if the temperature of the animal exceeds 42.7 degrees Celsius, the monitor lizard will die from heatstroke.


Long tongue endowed komodo dragon- This is a very important olfactory organ, like our nose. By sticking out its tongue, the monitor lizard catches odors. The tactility of the monitor lizard's tongue is not inferior to the sensitivity of smell in dogs. Hungry "dragon" is able to track down the victim on a single trace left by the animal a few hours ago.

juveniles komodo dragon painted in dark grey. Orange-red stripes-rings are located throughout the body of the animal. With age, the color of the monitor lizard changes, " the Dragon» acquires an even dark color.

Young monitor lizards, up to a year old, are small: their length reaches one meter. By the end of the first year of life, the monitor lizard already begins to hunt. Kids train on chickens, rodents, frogs, grasshoppers, crabs and the most harmless - snails. The matured "dragon" begins to hunt larger prey: goats, horses, cows, sometimes people. The monitor lizard gets close to its prey and attacks with lightning speed. Then he knocks the animal to the ground and tries to stun it as quickly as possible. In the event of an attack on a person, the monitor lizard first bites off the legs, then tears the body apart.

adults komodo dragon they eat their prey in exactly the same way - spreading the victim to pieces. After the victim of the monitor lizard is killed, the "dragon" rips open the belly and within twenty-five minutes eats the insides of the animal. The monitor lizard eats meat in large pieces, swallowing it along with the bones. To quickly pass food, the monitor lizard constantly throws its head up.

Locals tell how one day, while eating a deer, a monitor lizard pushed the animal's leg down his throat until he felt that it was stuck. After that, the beast made a sound similar to a rumble and began to violently shake its head, while falling on its front paws. monitor lizard fought until the moment when the paw flew out of his mouth.


While eating an animal the Dragon stands on four outstretched legs. In the process of eating, you can see how the monitor lizard's stomach is filled and pulled to the ground. Having eaten, the monitor lizard goes into the shade of the trees to digest food in peace and quiet. If something is left of the victim, young monitor lizards are drawn to the carcass. During the hungry dry season, pangolins feed on their own fat. Average life expectancy komodo dragon is 40 years old.

Komodo dragons have long ceased to be a curiosity ... But one unresolved question remains: how did such interesting animals get to Komodo Island in our time?

The appearance of a huge lizard is shrouded in mystery. There is a version that the Komodo dragon is the progenitor of the modern crocodile. One thing is clear: the monitor lizard living on Komodo Island is the largest lizard in the world. Paleontologists put forward a version that about 5 - 10 million years ago, the ancestors Komodo lizard appeared in Australia. And this assumption is confirmed by one weighty fact: the bones of the only known representative of large reptiles were found in Pleistocene and Pliocene deposits. australia.


It is believed that after the volcanic islands formed and cooled down, the lizard settled on them, in particular on Komodo island. But here again the question arises: how did the lizard get to the island, located 500 miles from Australia? The answer has not yet been found, but to this day, fishermen are afraid to go sailing near Komodo islands. Let's think that the "dragon" was helped by the sea current. If the version put forward is correct, then what did the lizards eat all the time when there were no buffaloes, no deer, no horses, no cows and pigs on the island ... After all, cattle was brought to the islands by man much later than voracious lizards appeared on them.
Scientists say that in those days giant turtles, elephants, whose height reached one and a half meters, lived on the island. It turns out that the ancestors of modern Komodo lizards hunted elephants, however, dwarf ones.
Anyway, but komodo dragons are "living fossils".

Domain:	eukaryotes
Kingdom:	Animals
Type:	chordates
Class:	reptiles
Squad:	scaly
Family:	monitor lizards
Genus:	monitor lizards
View:	komodo dragon

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 than other lizards stand to. These reptiles are separated into a separate family of monitor lizards, which includes 70 species.

Where does the Komodo dragon live?

Currently, the Komodo monitor lizard lives only on 5 islands in Indonesia: Komodo (about 1700 individuals), Gili Motang (about 100 individuals), Rinja (about 1300 individuals), Flores (about 2000 individuals) and Padan (information on habitat on this the island varies). But, according to scientists, Australia is the birthplace of this species of lizards. It was from this mainland that about 900,000 years ago the Komodo monitor lizards migrated to the islands, which at that time were not islands, but formed a single land area together with Australia. The subsequent rise in sea level isolated the islands from the mainland.

The largest lizard in the world chooses dry areas of plains, savannahs or tropical forests that are maximally warmed by the sun's rays. In especially dry and hot months, the animal tries to stay close to the beds of dry water bodies, the banks of which are covered with shady jungle thickets.

The largest monitor lizard in the world is a good swimmer and readily accepts water procedures: if necessary, it freely travels quite long distances by swimming in search of fish or sea turtles washed up on the coast. Some Komodo monitor lizards calmly swim to the numerous islets located between Komodo, Padar and Rindzhey.

To date, the population of large monitor lizards shrinking associated with degradation. And the reason for this is the meager nutritious diet in natural habitats and mass poaching.

Evolution

The skull of a modern Komodo monitor lizard and the fossilized remains of older specimens of this species. The evolutionary development of the Komodo dragon begins with the appearance of the genus Varanus, which, according to modern research, originated in Asia about 40 million years ago and migrated to Australia. Approximately 15 million years ago, a collision between Australia and Southeast Asia allowed the monitor lizards to colonize the area, the highlands of which later became the Indonesian archipelago, and inhabit islands such as remote Timor. The Komodo dragon was previously thought to have diverged from its Australian ancestor about 4 million years ago.

However, relatively recently found fossils in Queensland indicate that it developed for a long time in Australia before reaching Indonesia. Lower sea levels during the last Ice Age opened up vast areas of land that helped Komodo dragons colonize their modern habitats, but subsequent sea level rise, on the contrary, isolated them on the islands. This saved the species from the mass extinction of the Australian megafauna.

Appearance of the Komodo dragon

The size of these predatory reptiles is truly impressive. Wild Komodo monitor lizard in adulthood weighs about 75–90 kg with an average length of 2.5–2.6 m. Males are much larger than females. According to statistics, the maximum weight of females is 68–70 kg, with a length of 2.3 m. In an artificial habitat, an animal can reach more impressive dimensions. One such example is a zoo pet in St. Louis: weighing 166 kg, with a body length of 3.14 m.

They have a squat, stocky build with muscular limbs. The location on the sides and long claws contribute to convenient hunting and fast movement. It is also convenient to dig deep holes with such paws. They have a large tail, often comparable in size to the body. Unlike lizards, they do not drop it in case of danger, but begin to beat on the sides. The head is flat, on a short massive neck. Looking at her full face or profile, associations with a snake appear.

The skin is made up of two layers: scaly- the main one, with the imposition of small ossified growths. Young representatives of a brighter color. Orange-yellowish spotting is observed throughout the outer length, ending with stripes on the neck and tail. In a mature state, the skin is transformed, repainted in a gray-brown color with small yellow specks.

Teeth like spikes, sharp and long, one side attached to the jawbones. This is the perfect tool for tearing prey apart. The tongue is very long, sinuous, with a bifurcation at the end.

Lifestyle

The Komodo dragon is diurnal and does not hunt at night. At night they sleep soundly in their shelters. Although, only isolated cases of nocturnal activity of these animals were noted.

Despite the seeming sluggishness and slowness on land, the largest reptile in the world runs excellently over short distances, reaching speeds of up to 18-20 km per hour. And in order to get the coveted prey from a height, it gracefully enough rises on its hind legs, leaning on a strong tail. Young and not yet very massive Komodo monitors climb trees perfectly, spending a lot of time on branches and using hollows as safe shelters.

Preferring to live alone, these huge pangolins rarely converge in groups, a short association of monitor lizards can only cause a mating season and feeding, but these periods will be accompanied by constant skirmishes and fights, both between males and between females.

The long tongue that the Komodo dragon is endowed with is a very important olfactory organ. By sticking out its tongue, the monitor lizard catches odors. The tactility of the monitor lizard's tongue is not inferior to the sensitivity of smell in dogs. A hungry beast is able to track down a victim on a single trail left by the victim hours ago.

Komodo dragons are excellent swimmers. They can easily swim across small rivers, bays or overcome the distance to neighboring nearby islands. However, they cannot stay in the water for more than 15 minutes. And if they do not have time to get to land, they drown. Perhaps it was this factor that influenced the natural boundaries of the habitat of these animals.

Body temperature regulation

Getting out of their holes when the sun rises, monitor lizards prefer to sunbathe, completely spread out and stretching their paws. Thus, the Komodo dragon raises its body temperature. With a decrease in temperature, monitor lizards do not show activity and reaction speed, their state is more sleepy than mobile. Having received a charge of solar energy, they bypass their possessions, zealously observing whether there are any uninvited guests on its territory.

The temperature of his body directly depends on the size of the Komodo monitor lizard - the older and larger the lizard, the longer he is able to retain heat in himself, keeping it even at night, and the less time he will spend in the morning warming up the body.

He does not tolerate heat well, his body does not have sweat glands. And if the temperature of the animal exceeds 42.7 ° C, the monitor lizard will die from heat stroke.

Feeding the Komodo dragon

The diet of the monitor lizard is varied. While the lizard is still in its infancy, it can even eat insects. But with the growth of an individual, its prey increases in weight. While the monitor lizard has not reached a weight of 10 kg, it feeds on small animals, sometimes climbing to the tops of trees after them.

True, such “kids” can easily attack game that weighs almost 50 kg. But after the monitor lizard gained weight more than 20 kg, only large animals make up its diet. and the monitor lizard waits at a watering place or near forest paths. Seeing the prey, the predator pounces, trying to knock down the victim with a blow of the tail.

Often, such a blow immediately breaks the legs of the unfortunate. But more often, the monitor lizard tries to bite the victim's tendons on the legs. And even then, when the immobilized victim cannot escape, he tears the still living animal into large pieces, tearing them out of the neck or abdomen. Not a particularly large animal, the monitor lizard eats whole (for example, a goat). If the victim did not immediately give up, the monitor lizard will overtake her anyway, guided by the smell of blood.

Varan is gluttonous. At one time, he easily eats about 60 kg of meat, if he weighs 80. According to eyewitnesses, one is not too big female komodo dragon(weighing 42 kg) finished with a 30 kg boar in 17 minutes.

It is clear that it is better to stay away from such a cruel, insatiable predator. Therefore, from the areas where monitor lizards settle, for example, reticulated lizards, which simply cannot be compared in hunting qualities with this beast, disappear.

How does a Komodo dragon hunt?

In the arsenal of this predator, there are many ways to get food. Sometimes the monitor lizard hunts from some kind of ambush - a stone, a tree, a bush. Most often, he waits in this way for food in the forests. When any animal approaches him, he hits him with a sweep of his tail. After such a blow, the animal loses consciousness or its paws are broken.

The monitor lizard hunts for large ungulates in a different way. Naturally, he can not cope with a huge buffalo in a fair fight. Moreover, many Komodo dragons die from their horns or hooves.

Therefore, they do not try to engage in a fight with him. They sneak up on him and just bite. After that, the buffalo is doomed.

The fact is that in the saliva of this predator there are many pathogenic bacteria. These bacteria, getting into the bloodstream, cause sepsis (infection) and after a while the bitten one dies.

All this time, the monitor lizard follows the victim on the heels and waits in the wings. During this time, other lizards will smell the rotting wound, and they will also crawl and wait for the death of the victim.

Komodo dragon venom

Previously, it was believed that the saliva of the Komodo monitor lizard contains only a harmful "cocktail" of pathogenic bacteria, to which the predatory lizard is immune. However, relatively recently, scientists have determined that the monitor lizard has a pair of poisonous glands located on the lower jaw and producing special toxic proteins that cause a bitten victim to reduce blood clotting, hypothermia, paralysis, lower blood pressure and loss of consciousness.

The glands have a primitive structure: they do not have channels in the teeth, as, for example, in snakes, but open at the base of the teeth with ducts. Thus, the bite of a Komodo monitor lizard is poisonous.

reproduction

Animals of this species reach puberty approximately in the fifth - tenth year of life, to which only a small part of the born monitor lizards survive. The sex ratio in the population is approximately 3.4:1 in favor of males. Possibly, this is a mechanism for regulating the abundance of the species in the conditions of insular habitation.

Since the number of females is much less than the number of males, during the breeding season between males occur ritual fights for the female. At the same time, monitor lizards stand on their hind legs and, clasping their opponent's front limbs, try to knock him down.

In such battles, mature hardened individuals usually win, young and very old males retreat. The victorious male presses the opponent to the ground and scratches him with his claws for a while, after which the loser moves away.

Male Komodo dragons are much larger and more powerful than females. During mating, the male twitches his head, rubs his lower jaw against her neck and scratches the back and tail of the female with his claws.

Mating occurs in winter, during the dry season. After mating, the female is looking for a place to lay eggs. They are often the nests of weedy chickens, building compost heaps - natural incubators from fallen leaves for thermoregulation of the development of their eggs. Having found a pile, the female monitor lizard digs a deep hole in it, and often several, in order to divert the attention of wild boars and other predators that eat eggs.

Egg laying occurs in July-August, the average clutch size of the Komodo dragon is about 20 eggs. Eggs reach a length of 10 cm and a diameter of 6 cm, weigh up to 200 g. The female guards the nest for 8–8.5 months until the cubs hatch.

Young lizards appear in April-May. Having been born, they leave their mother and immediately climb the neighboring trees. To avoid potentially dangerous encounters with adult monitor lizards, young monitor lizards spend the first two years of their lives in the crowns of trees, where they are inaccessible to adults.

Found in Komodo dragons parthenogenesis. In the absence of males, the female can lay unfertilized eggs, which was observed in the Chester and London zoos in England. Since male monitor lizards have two identical chromosomes, and females, on the contrary, differ, and at the same time a combination of identical ones is viable, all cubs will be male. Each egg that is laid contains either a W or a Z chromosome (in Komodo dragons, ZZ is male and WZ is female), then gene duplication occurs. The resulting diploid cells with two W chromosomes die, and those with two Z chromosomes develop into new lizards.

The ability of these reptiles to reproduce sexually and asexually is probably associated with the isolation of their habitat - this allows them to establish new colonies if, as a result of a storm, females without males are thrown onto neighboring islands.

Enemies of the Komodo dragon in nature

In its natural habitat, the Komodo monitor lizard, which has reached adult age, has almost no enemies. A threat to a lizard can only be larger relatives, a person or. Although sometimes a giant Indonesian monitor lizard, with resistance, can be maimed by its large prey - buffaloes and wild boars. Teenage monitor lizards are often preyed upon by snakes and birds of prey.

It is rare that giant Komodo dragons are tamed and settled in zoos. But, surprisingly, monitor lizards quickly get used to a person, they can even be tamed. One of the representatives of monitor lizards lived in the London Zoo, freely ate from the hands of the beholder and even followed him everywhere.

Nowadays, Komodo monitor lizards live in the national parks of the Rindja and Komodo islands. They are listed in the Red Book, so hunting for these lizards is prohibited by law, and according to the decision of the Indonesian committee, catching monitor lizards is carried out only with special permission.

Human danger

Komodo monitor lizards are quite aggressive and are one of the predators that are potentially dangerous to humans. There are several cases of monitor lizard attacks on people, including fatal ones. At the moment, their number only continues to grow.

This is probably due to the fact that there are few human settlements on the islands, but they are, and these are usually poor fishing villages, the population of which is growing rapidly (800 people according to 2008 data), as a result of which the likelihood of unpleasant encounters with people increases. wild predators. Since killing Komodo monitor lizards is currently prohibited by law, they eventually cease to be afraid of the people who once hunted them.

The situation is also complicated by the fact that the local population used to feed monitor lizards to avoid attacks by hungry animals, and now a ban has also been imposed on such actions. In famine years, especially in drought, Komodo monitor lizards come very close to settlements, they are especially attracted by the smell of human excrement, domestic animals, caught fish, etc. There are well-known cases of monitor lizards digging up human corpses from shallow graves. Recently, however, Muslim Indonesians living on the islands have been burying the dead by covering them with dense cast cement slabs, inaccessible to monitor lizards. Rangers usually capture potentially dangerous individuals and move them to other areas of the island.

The bites of Komodo monitor lizards are extremely dangerous - even a relatively small monitor lizard can easily tear out muscles from the thigh or humerus and cause large-scale blood loss with the resulting pain shock. The number of deaths due to untimely provision of first aid (and, as a result, the onset of collapse) reaches 99%. As with crocodile bites, it is quite common to experience sepsis after being bitten by monitor lizards.

Since adult monitor lizards have a very good sense of smell, they can locate the source of even the faintest smell of blood at a distance of more than 5 km.

Several cases have been documented of Komodo dragons attempting to attack tourists with minor open wounds or scratches. A similar danger threatens women who visit the islands of habitat of Komodo monitor lizards during menstruation. Tourists are usually warned of the potential danger by rangers; all groups of tourists are usually accompanied by rangers, armed with long poles with a forked end to protect themselves from possible attacks. Such security measures are usually sufficient, since monitor lizards in tourist areas are usually well fed and tamed enough to humans, not showing aggression without obvious provocation.

1. Komodo dragons belong to the goanna family. The body length of an adult monitor lizard - 3 meters, and the weight reaches 90 kilograms.
2. The lifespan of a monitor lizard in the wild is on average 30 years.
3. monitor lizards rarely attack people, and, nevertheless, cases of attack are known.
4. A long and forked tongue is necessary for predators in order to capture any smells. This is very important when hunting. In addition to the language, a successful body color also helps them to hunt, thanks to which they successfully disguise themselves and wait patiently.
5. To get a victim monitor lizard just bite her and then wait for her to die from blood poisoning. The fact is that monitor lizard saliva contains more 50 dangerous bacteria which, when released into the bloodstream, cause infection. A keen sense of smell helps the monitor lizard track down an infected animal in order to eat it later. Interestingly, at one time this creature is able to eat up to 80% of own weight.
6. komodo dragon- a hermit. Together with their relatives, monitor lizards are found only during mating. Every day, males guard their territory, bypassing several kilometers. Sometimes, in search of new housing, males swim to other islands. Monitor lizards live in burrows, since it is burrows that regulate body temperature well.
7. monitor lizards very vulnerable creatures due to too limited habitat. In addition, reptiles are vulnerable due to constant earthquakes, volcanic eruptions, illegal trapping, and a lack of food. For a long time, animals were hunted, as a result of which today monitor lizards listed in the Red Book.
8. AT 1980 In Indonesia, the Komodo National Park was opened, which helped protect monitor lizards from extinction.
9. At Komodo monitor lizards excellent vision. They can see their prey even from a distance. 300 meters. And yet the main sense organ monitor lizards smell is considered.
10. After eating at monitor lizards the belly is greatly enlarged. However, if they urgently need to flee from enemies, they are able to devastate it on their own.
11. When kept in captivity (these cases are very rare), giant reptiles quickly get used to humans and become almost tame. One such representative of the species lived in the London Zoo, he responded to the nickname, took food from the hands of a person and ran on the heels of his caretakers.
12. In 2003, Nature Australia published a brief report on a young varanihe named Kraken, who lives at the Washington Zoo and loves to play with toys. The observation of the Kraken was carried out by Dr. Gordon Burkhart and his colleagues from the University of Tennessee. Scientists studied the play behavior of the monitor lizard for two years and during this time recorded 31 videos in which you can see how the lizard plays with various objects - a rubber ring, a bucket filled with toilet paper rolls, a handkerchief and a tennis shoe.

International scientific name

Varanus komodoensis Ouwens,

area
conservation status

Systematics on Wikispecies

Images at Wikimedia Commons

ITIS NCBI EOL

Lifestyle

Komodo dragons lead a solitary lifestyle, uniting in non-permanent groups during feeding and during the breeding season.

The Komodo dragon prefers dry, well-heated areas, and, as a rule, lives on arid plains, in savannahs and dry tropical forests, at low altitudes. In the hot season (May-October) it adheres to dry riverbeds with jungle-covered banks. Often comes ashore in search of carrion washed ashore. Willingly enters sea water, swims well and can even swim across to a neighboring island, having covered a considerable distance.

When running over short distances, the monitor lizard is able to reach speeds of up to 20 km / h. To get food at a height (for example, on a tree), it can stand on its hind legs, using its tail as a support. Young animals climb well and spend a lot of time in trees.

Monitor lizards use burrows 1-5 m long as shelters, which they dig with strong paws with long, curved and sharp claws. Hollow trees serve as a refuge for young monitor lizards.

In the wild, adults have no natural enemies. Young monitor lizards are eaten by snakes, civets and birds of prey.

The natural lifespan of monitor lizards in nature is probably around 50 years. In captivity, no cases have been noted so far that the Komodo monitor lizard has lived for more than 25 years.

Nutrition

Young Komodo dragon near the carcass of an Asian water buffalo

Monitor lizards feed on a wide variety of animals - both vertebrates and invertebrates. They may eat insects (mainly orthoptera), crabs, fish, sea turtles, lizards, snakes, birds, mice and rats, civets, deer, wild boars, feral dogs, goats, buffaloes, and horses.

Cannibalism is common among Komodo monitor lizards, especially in famine years: adults often eat young and smaller monitor lizards.

On the islands inhabited by Komodo monitors, there are no predators larger than them, so adult monitor lizards are at the top of the food chain. They hunt relatively large prey from an ambush, sometimes knocking the victim down with blows from a powerful tail, often breaking the legs of the victim. Large adult Komodo dragons feed mainly on carrion, but they often get this carrion in an unusual way. So, having tracked down a deer, a wild boar or a buffalo in the bushes, the monitor lizard attacks and seeks to inflict a lacerated wound on the animal, into which poison and many bacteria from the monitor lizard's oral cavity are introduced. Even the largest male monitor lizards do not have enough strength to immediately overcome a large ungulate animal, but as a result of such an attack, the victim’s wound becomes inflamed, blood poisoning occurs, the animal gradually weakens and dies after a while. The monitor lizards are left only to follow the victim until she dies. The time for which it dies varies depending on its size. In buffalo, death occurs after 3 weeks. Monitor lizards have a good sense of smell and locate corpses by smell using a long forked tongue. Monitor lizards come from all over the island to the smell of carrion. In feeding areas, fights between males are frequent in order to establish and maintain a hierarchical order (usually non-fatal, although scars and traces of wounds are noticeable).

The Komodo dragon can swallow very large prey or large pieces of food, which is facilitated by the movable connection of the bones of the lower jaw and a capacious, expandable stomach.

Females and juveniles prey on smaller animals. Cubs can even stand up on their hind legs to reach small animals that are too high for adult relatives.

Currently, due to a sharp decline in the number of large wild ungulates on the islands due to poaching, even adult male monitor lizards are forced to switch to smaller prey. Because of this, the average size of monitor lizards is gradually decreasing and now is about 75% of the average size of a mature individual 10 years ago. Hunger sometimes causes the death of monitor lizards.

reproduction

Animals of this species reach puberty approximately at the tenth year of life, to which only a small part of the born monitor lizards survive. The sex ratio in the population is approximately 3.4:1 in favor of males. Possibly, this is a mechanism for regulating the abundance of the species in the conditions of insular habitation. Since the number of females is much less than the number of males, during the breeding season, ritual fights take place between males for the female. At the same time, monitor lizards stand on their hind legs and, clasping their opponent's front limbs, try to knock him down. In such battles, mature hardened individuals usually win, young and very old males retreat. The victorious male presses the opponent to the ground and scratches him with his claws for a while, after which the loser moves away.

Male Komodo dragons are much larger and more powerful than females. During mating, the male twitches his head, rubs his lower jaw against her neck and scratches the back and tail of the female with his claws.

Mating occurs in winter, during the dry season. After mating, the female is looking for a place to lay eggs. They are often nests of weed chickens erecting compost heaps - natural incubators from fallen leaves for thermoregulation of the development of their eggs. Having found a pile, the female monitor lizard digs a deep hole in it, and often several, in order to divert the attention of wild boars and other predators that eat eggs. Egg laying occurs in July-August, the average size of a Komodo dragon clutch is about 20 eggs. Eggs reach a length of 10 cm and a diameter of 6 cm, weigh up to 200 g. The female guards the nest for 8-8.5 months until the cubs hatch. Young lizards appear in April-May. Having been born, they leave their mother and immediately climb the neighboring trees. To avoid potentially dangerous encounters with adult monitor lizards, young monitor lizards spend the first two years of their lives in the crowns of trees, where they are inaccessible to adults.

Parthenogenesis has been found in Komodo dragons. In the absence of males, the female can lay unfertilized eggs, which was observed in the Chester and London zoos in England. Since male monitor lizards have two identical chromosomes, and females, on the contrary, differ, and at the same time a combination of identical ones is viable, all cubs will be male. Each egg that is laid contains either a W or a Z chromosome (in Komodo dragons, ZZ is male and WZ is female), then gene duplication occurs. The resulting diploid cells with two W chromosomes die, and those with two Z chromosomes develop into new lizards. The ability for sexual and asexual reproduction in these reptiles is probably associated with the isolation of the habitat - this allows them to establish new colonies if, as a result of a storm, females without males are thrown onto neighboring islands.

I

It has traditionally been believed that the effects of Komodo dragon bites (severe inflammation at the site of the bite, sepsis, etc.) are caused by bacteria living in the monitor's mouth. Auffenberg pointed to the presence of pathogenic microflora in the saliva of the Komodo dragon, including Escherichia coli, Staphylococcus sp., Providencia sp., Proteus morgani and Proteus mirabilis. It has been suggested that bacteria enter the body of lizards when feeding on carrion, as well as when feeding jointly from other monitor lizards. But in oral samples taken from fresh-eating zoo monitors, researchers at the University of Texas found 57 different strains of bacteria found in wild monitors, including Pasteurella multocida. Besides, Pasteurella multocida from monitor lizard saliva showed much more intensive growth on nutrient media than obtained from other sources.

Recently, however, Australian scientists working with related monitor lizards have found that at least some species of monitor lizards are venomous themselves. In late 2005, a team of scientists from the University of Melbourne suggested that the great monitor lizard ( Varanus giganteus), other species of monitor lizards, as well as dragons, may have toxic saliva, and that the effects of the bites of these lizards were caused by mild intoxication. Studies have shown the toxic effects of the saliva of several species of monitor lizards (particularly the spotted monitor lizard ( Varanus varius) and Varanus scalaris), as well as some agama lizards - in particular, the bearded agama ( Pogona barbata). Prior to this study, there were conflicting data on the toxic effects of the saliva of some monitor lizards, such as the gray monitor lizard ( Varanus griseus).

In 2009, the same researchers published further evidence that Komodo dragons have a venomous bite. An MRI scan showed two venom glands in the lower jaw. They removed one of these glands from a terminally ill monitor lizard at the Singapore Zoo and found that it secretes a venom containing various toxic proteins. The functions of these proteins include inhibition of blood clotting, lowering blood pressure, muscle paralysis, and the development of hypothermia leading to shock and unconsciousness in the bitten victim.

Some scientists have proposed a hypothetical non-ranking group to unite snakes, monitor lizards, gila-tooths, fusiformes and iguanas. Toxicofera. The association is based on the presence of toxic components in saliva and assumes that all "poisonous" groups have one ancestor (which is not indisputable).

The venom gland of monitor lizards is more primitive than that of poisonous snakes. The gland is located in the lower jaw directly below the salivary glands, its ducts open at the base of the teeth, and do not exit through special channels in poisonous teeth, like in snakes. In the oral cavity, poison and saliva mix with decaying food, forming a mixture in which many different bacteria multiply.

Human danger

Komodo monitor lizards are one of the species potentially dangerous to humans, although they are less dangerous than crocodiles or sharks, and do not pose a direct danger to adults. Nevertheless, there are several cases of monitor lizards attacking people, when monitor lizards mistook a person for food familiar to a monitor lizard (carrion, birds, etc.) due to some smell. Komodo dragon bites are extremely dangerous. After a bite, you should immediately consult a doctor. The number of deaths due to untimely medical care (and, as a result, blood poisoning) reaches 99%. Children are especially vulnerable. Monitor lizards may well kill a child under 10 years old or cause severe injury. There are documented cases of children dying from monitor lizard attacks. There are few human settlements on the islands, but they exist and their population is growing rapidly (800 people according to 2008 data). As a rule, these are poor, fishing villages. In famine years, especially in drought, monitor lizards come close to settlements. They are especially attracted by the smell of human excrement, fish, etc. Cases of monitor lizards digging up human corpses from shallow graves are well known. Recently, however, Indonesian Muslims living on the islands have been burying the dead, covering them with dense cast cement slabs, inaccessible to monitor lizards. Rangers usually capture individuals and move them to other areas of the island. Killing monitor lizards is prohibited by law.

Since adult monitor lizards have a very good sense of smell, they can locate the source of the smell of blood up to 5 km away. Several cases have been documented of Komodo dragons attempting to attack tourists with minor open wounds or scratches. A similar danger threatens women who visit the islands of habitat of Komodo monitor lizards, while in the menstrual cycle. Tourists are usually warned of the potential danger by rangers; all groups of tourists are usually accompanied by rangers, armed with long poles with a forked end to protect themselves from possible attacks.

Komodo dragon on Indonesian coin

conservation status

The Komodo monitor lizard is a narrow-range species that is endangered due to human activities. Listed in the IUCN Red List and Appendix I of the CITES Convention on International Trade in Species. In 1980, to protect the species from extinction, Komodo National Park was organized, which now regularly organizes sightseeing, ecological and adventure tours.

see also

Notes

1. Ananyeva N. B., Borkin L. Ya., Darevsky I. S., Orlov N. L. Five-language dictionary of animal names. Amphibians and reptiles. Latin, Russian, English, German, French. / under the general editorship of acad. V. E. Sokolova. - M .: Rus. yaz., 1988. - S. 269. - 10,500 copies. - ISBN 5-200-00232-X
2. A. G. Bannikov , I. S. Darevsky , M. N. Denisova Life of animals. Amphibians. Reptiles / ed. V. E. Sokolova. - 2nd ed. - M .: Education, 1985. - V. 5. - S. 245. - 300,000 copies.
3. Ciofi, Claudia The Komodo Dragon (English) . Scientific American (March 1999). archived
4. Dragon's Paradise Lost: Palaeobiogeography, Evolution and Extinction of the Largest-Ever Terrestrial Lizards (Varanidae) (English) . plosone. Archived from the original on February 21, 2012. Retrieved March 6, 2011.
5. Monitor lizards of Komodo Island have been found to be poisonous. Living water. Archived from the original on February 21, 2012. Retrieved March 6, 2011.

The halo of mystery surrounding the Komodo, or Komodo, monitor lizards is full of numerous myths and legends. This is not surprising: lizards, reaching three meters in length and one and a half centners in weight, have long been nicknamed dragons. And their secretive way of life from scientists and their love to feast on corpses, including human ones, only added mystics in rare descriptions.

One of the quite scientific myths is the way monitor lizards kill their prey. Until recently, even in scientific circles, it was believed that dragons infect their prey with harmful bacteria living in their uncleaned teeth, and then wait for the microbes and their toxins to do their dirty work.

Brian Fry of the Australian University of Melbourne and colleagues showed that

dragons - first of all, the owners of albeit small, but very dangerous poisonous glands, forcing prey to die from blood loss.

Since recently the number of large ungulate mammals in the habitat of dragons has significantly decreased, the average size of individuals has also decreased significantly. But even now, one laceration is enough to lay down a mammal that is much larger than a monitor lizard. It remains only to guess who the megalanias were hunting for, if their poisonous glands were 5 times larger than those of Komodo dragons and could simultaneously release up to 1.2 mg of poison.

The Komodo dragon is the largest lizard species in existence today.

Adult specimens of Komodo monitor lizards reach a weight of 70 kg and a body length of up to 3 m. It is worth noting that in captivity this monitor lizard can be even larger.

The adult has a dark brown color with a yellow speck. The cutting edge of the monitor lizard's teeth is somewhat reminiscent of a saw blade. This structure of the tooth allows the animal to easily butcher the carcass of its prey.

Habitat of Komodo monitor lizards

The habitat of this lizard is very localized. It is distributed only on the islands of Indonesia, such as Flores, Rinka, Jili Motang and Komodo. From the name of the last island, in fact, the name of this species comes. Research shows that these lizards left Australia 900,000 years ago and moved to the islands.

Komodo dragon lifestyle

These lizards form groups only during the mating season and during feeding. The rest of the time, stay alone. Activity is shown mainly during daylight hours. Being in the shade for the first part of the day, they go hunting in the second half, when the heat subsides somewhat. They spend the night in shelters, from which they crawl out only in the morning.

Monitor lizard keeps dry areas well-lit by the sun. Usually these are savannahs, dry forests of the tropics and arid plains. From May to October it inhabits dry riverbeds. In order to profit from carrion, it often visits the coast. Varan is an excellent swimmer. Cases have been noted when these lizards even swam from island to island.

Burrows up to 5 meters deep serve as a refuge for monitor lizards. The lizards dig these holes on their own. In this they are helped by their powerful paws with sharp claws. Younger monitor lizards, unable to dig their own similar holes, find shelter in hollows and cracks in trees. The monitor lizard is able to reach speeds of up to 20 km/h for a short time. To get to food at a certain height, the monitor lizard is able to rise on its hind legs.

In their natural habitat, adult lizards do not encounter enemies. However, young animals can often become prey for birds of prey and snakes.

In captivity, these lizards rarely live up to 25 years, although, according to some reports, monitor lizards can live up to half a century in the wild.

Feeding the Komodo dragon

Komodo dragons feed on a variety of animals. The diet includes fish, crabs, lizards, turtles, rats, snakes. The lizard also feeds on birds and insects. Of the large animals, deer, horses and even buffaloes sometimes become prey. In especially hungry years, monitor lizards do not disdain to eat individuals of their own species. In this case, as a rule, very small individuals and young animals become victims of cannibalism.

Adults very often feed on carrion. Sometimes the method of obtaining such carrion is very interesting.

The monitor lizard, having tracked down a large animal, suddenly attacks it, inflicting wounds on it, into which poison and bacteria from the oral cavity of this lizard will get. The monitor lizard then follows its prey in anticipation of its death.

Such persecution can last from several hours to several weeks. These lizards feel carrion well thanks to their surprisingly developed sense of smell.

Today, poaching within the habitat of monitor lizards causes great harm and reduces the number of large ungulates. Because of this, monitor lizards are often forced to settle for smaller prey. The consequence of this state of affairs is a decrease in the average size of adult Komodo dragons. This size has decreased by 25% over the past 10 years.

Reproduction of Komodo dragons

Sexual maturity comes to these lizards in the tenth year of existence. Until this time, only a small part of individuals survive. As for the sexual structure, females occupy only 23% of the entire population.

Due to the huge competition during the mating season, there are fights between males for females. In these fights, adult experienced individuals often win. The old and the young, as a rule, remain out of work.

The mating season for monitor lizards begins in winter. Having mated, the female is taken to search for a place for masonry. As a rule, such places are compost heaps created by weed chickens as nests. These heaps are natural incubators for Komodo dragon eggs. In these heaps, females dig deep burrows. Laying takes place during the summer period from July to August. There are about 20 eggs in one clutch. With a diameter of 6 cm and a length of 10 cm, the eggs weigh about two hundred grams.