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LIZARDS(Lacertilia, Sauria), suborder of reptiles. As a rule, small animals with well-developed limbs, the closest relatives of snakes. Together they form a separate evolutionary line of reptiles. The main distinguishing feature of its representatives is the paired copulatory organs of the male (hemipenises), located on both sides of the anus at the base of the tail. These are tubular formations that can turn inside out or retract inward like the fingers of a glove. Everted hemipenis serve for internal fertilization of the female during mating.

Lizards and snakes form a squamous squad - Squamata (from Latin squama - scales, as a sign that the body of these reptiles is covered with small scales). One of the recurring trends in the evolution of its representatives was the reduction or loss of limbs. Snakes, one of the lines of squamates with reduced limbs, form the suborder Serpentes. The suborder of lizards combines several very different evolutionary lines. For simplicity, we can say that "lizards" are all scaly, except for snakes.

Most lizards have two pairs of limbs, visible openings of the external auditory canal, and a movable eyelid; but some of them lack these signs (as in all snakes). Therefore, it is more reliable to focus on the features of the internal structure. For example, all lizards, even legless ones, retain at least the rudiments of the sternum and shoulder girdle (the skeletal support of the forelimbs); both are completely absent in snakes.

Distribution and some species.

Lizards are widely distributed throughout the world. Absent in Antarctica, they are found from the southern tip of other continents to the south of Canada in North America and to the Arctic Circle in that part of Europe where the climate is moderated by warm ocean currents. Lizards are found from below sea level, for example in Death Valley in California, up to 5500 m above sea level in the Himalayas.

Known ca. 3800 of their modern species. The smallest of them is the round-toed gecko ( Sphaerodactylus elegans) from the West Indies, only 33 mm long and weighing about 1 g, and the largest is the Komodo dragon ( Varanus komodoensis) from Indonesia, which can reach 3 m in length with a mass of 135 kg. Despite the widespread belief that many lizards are poisonous, there are only two such species - vest ( Heloderma suspectum) from the southwestern United States and its sister escorpion ( H. horridum) from Mexico.

paleontological history.

The most ancient fossil remains of lizards date back to the late Jurassic (about 160 million years ago). Some of their extinct species were huge. It is assumed that Megalania, which lived in Australia in the Pleistocene (about 1 million years ago), reached a length of approx. 6 m; and the largest of the mosasaurs (a fossil family of long, slender fish-like aquatic lizards related to monitor lizards) is 11.5 m. Mosasaurs inhabited the coastal sea waters of various parts of the planet approx. 85 million years ago. The closest modern relative of lizards and snakes is a rather large tuatara, or tuatara ( Sphenodon punctatus) from New Zealand.

Appearance.

The background coloration of the back and sides of most lizards is green, brown, gray or black, often with a pattern in the form of longitudinal and transverse stripes or spots. Many species are able to change color or its brightness due to the dispersion and aggregation of pigment in special skin cells called melanophores.

The scales are both small and large, they can be located close to each other (like tiles) or overlap (like tiles). Sometimes they are transformed into spikes or ridges. In some lizards, such as skinks, there are bony plates called osteoderms inside the horny scales, which give the integument additional strength. All lizards periodically molt, throwing off the outer layer of the skin.

The limbs of lizards are arranged differently, depending on the lifestyle of the species and the surface of the substrate on which it usually moves. In many climbing forms, such as anoles, geckos and some skinks, the lower surface of the fingers is expanded into a pad covered with bristles - branched hair-like outgrowths of the outer layer of the skin. These bristles catch on the slightest irregularities in the substrate, which allows the animal to move along a vertical surface and even upside down.

Both the upper and lower jaws of lizards are equipped with teeth, and in some they are also located on the palatine bones (roof of the mouth). On the jaws, the teeth are held in two ways: acrodontally, almost completely fused with the bone, usually along its edge and not changing, or pleurodontally - loosely attached to the inner side of the bone and regularly replaced. Agamas, amphisbaenes, and chameleons are the only modern lizards with acrodont teeth.

Sense organs.

The eyes of lizards are developed in different ways, depending on the species - from large and well-seeing in diurnal forms to small, degenerative and covered with scales in some burrowing taxa. Most have a mobile scaly eyelid (only the lower one). Some medium-sized lizards have a transparent "window" on it. In a number of small species, it occupies a larger or entire area of ​​the eyelid, which is attached to the upper edge of the eye, so that it is constantly closed, but sees as if through glass. Such "glasses" are characteristic of most geckos, many skinks and some other lizards, whose eyes as a result are unblinking, like those of snakes. Lizards with a mobile eyelid have a thin nictitating membrane, or third eyelid, under it. This is a transparent film that can move from side to side.

Many lizards have retained the “third eye” peculiar to the ancestors of the parietal, which is not able to perceive the form, but distinguishes between light and darkness. It is believed to be sensitive to ultraviolet radiation and to help regulate sun exposure, as well as other behaviors.

Most lizards have a noticeable opening in the shallow external auditory meatus, which ends with the tympanic membrane. These reptiles perceive sound waves with a frequency of 400 to 1500 Hz. Some groups of lizards have lost the auditory opening: it is either covered by scales or has disappeared as a result of narrowing of the auditory canal and eardrum. In general, these "earless" forms can perceive sounds, but, as a rule, are worse than the "eared" ones.

Jacobson's (vomero-nasal) organ- chemoreceptor structure located in the anterior part of the palate. It consists of a pair of chambers that open into the oral cavity with two small openings. With its help, lizards can determine the chemical composition of substances that have entered their mouths and, more importantly, are in the air and have fallen on their protruding tongue. Its tip is brought to the Jacobson organ, the animal “tastes” the air (for example, to the proximity of prey or danger) and reacts accordingly.

Reproduction.

Initially, lizards are oviparous animals, i.e. lay shelled eggs that develop for several weeks outside the mother's body before the young hatch from them. However, many groups of lizards have developed ovoviviparity. Their eggs are not covered with a shell, they remain in the oviducts of the female until the completion of embryonic development, and already "hatched" cubs are born. Truly viviparous can only be considered widespread South American skinks of the genus Mabuya. Their tiny, yolkless eggs develop in the oviducts, probably fed by the mother through the placenta. The placenta in lizards is a special temporary formation on the wall of the oviduct, in which the capillaries of the mother and the embryo come close enough to each other so that the latter receives oxygen and nutrients from her blood.

The number of eggs or young in a brood varies from one (in large iguanas) to 40–50. In several groups, for example, in most geckos, it is constant and equal to two, while in skinks and a number of American tropical geckos, the cub in the brood is always one.

Age of puberty and life expectancy.

Puberty in lizards generally correlates with body size; in small species it lasts less than a year, in large species it lasts several years. In some small forms, most adults die after laying eggs. Many large lizards live up to 10 years or more, and one brazilian, or brittle spindle ( Anguis fragilis), reached 54 years of age in captivity.

Enemies and ways of protection.

Lizards are attacked by almost all animals that can grab and overpower them. These are snakes, birds of prey, mammals and humans. Methods of defense against predators include morphological adaptations and special behavioral techniques. If you get too close to some lizards, they take a threatening posture. For example, the Australian frilled lizard ( Chlamydosaurus kingii) suddenly opens its mouth and raises a wide bright collar formed by a skin fold on the neck. Obviously, the effect of surprise plays a role, scaring off enemies.

If many lizards are grabbed by the tail, they throw it off, leaving the enemy with a writhing fragment that distracts his attention. This process, known as autotomy, is facilitated by the presence of a thin non-ossifying zone in the middle of all caudal vertebrae except those closest to the trunk. The tail is then regenerated.

lizards- a suborder of scaly reptiles, the largest group of modern reptiles, currently numbering more than 3,500 species, united in 20 families and almost 350 genera. Lizards can be found on all continents except Antarctica. and each of them is characterized by certain groups of these animals. In Europe, these are real lizards, in Asia - agamas and some geckos, in Africa - belt-tails, and in Australia - monitor lizards and scales.

The greatest species diversity of lizards is in the tropical and subtropical zones of the Earth, in countries with a temperate climate there are fewer of them, and only one species reaches the Arctic Circle - the viviparous lizard (Lacerta vivi-raga). Lizards inhabit the most diverse biotopes of our planet - from waterless deserts to tropical rainforests and subalpine meadows, descend into the deepest gorges and climb mountains to a height of up to 5 thousand meters above sea level, to the zone of eternal snow.

Most lizards live on the surface of the earth, but many of them penetrate into its thickness (these are many skinks) or rush up into the crowns of trees (many agamas and geckos). And lizards like the flying dragon (Draco volans) or the blade-tailed gecko (Ptycho-zoon kuhli) are trying to do again what reptiles have already done many millions of years ago - master the airspace. The marine element is not alien to lizards - marine iguanas (Amblyrhync-hus cristatus) live on the Galapagos Islands, perfectly swimming and diving for seaweed, which they feed on.

The appearance of lizards is so diverse that it is difficult to name any characteristic feature. Moreover, lizards have so many features in common with snakes that sometimes even a specialist can not easily distinguish between them. It is not for nothing that lizards and snakes are only suborders in one detachment. Thus, representatives of 7 families of lizards are completely or partially devoid of legs; in our country, these are the spindle (Anguis fragilis) and yellowbell (Ophisaurus apodus).

In naked eyes, like snakes, the eyelids have grown together and become transparent, in many lizards there are barely noticeable (or even completely absent) ear openings, and, finally, there are poisonous lizards - poisonous teeth that live in the USA and Mexico. Many lizards have a very bizarre appearance due to the presence of various skin outgrowths and folds in the form of ridges, bumps and horns. As an example, it is enough to recall the Australian lizard - Moloch (Moloch horridus), absolutely harmless, but with a frightening appearance.

The color of many lizards is variegated and varied, and in a number of species it can vary depending on the physiological state. There are such lizards in our country. Thus, the color of the steppe agama (Traelus sanguinolenta) becomes brighter at high temperatures or during mating tournaments - at this time, the males have a characteristic blue “beard”. However, in most lizards, the coloring is camouflage - making them invisible against the surrounding background.

For example, lizards that live in the desert are often colored yellow, gray or brown, and in the green of the rainforest they are bright green. The appearance of lizards is closely related to the way of life. Arboreal species have tenacious claws and a tail, or special fingertips that allow them to hold on to branches in the most unthinkable positions.

Some geckos, thanks to such pads, covered with numerous microscopic hooks, are even kept on glass. Such are the currents (Gecko gekko), day-time Madagascar (Phelsuma) and many other geckos. In burrowing lizards, the limbs are reduced or absent altogether, the body is serpentine. These features are most pronounced in worm-like lizards of the genus Dibamus, common in Indo-China, the Indo-Australian and Philippine Islands, and New Guinea.

Most lizards move very quickly, but I especially want to note the American cnemidophorus (Cnemidophorus), moving on its hind legs using its tail to maintain balance. For the speed of movement, these lizards received a second name - runner lizards. But the Australian frilled agama (Chlamydosaurus kingi) is not inferior to them in terms of speed of movement. A helmeted basilisk (Basiliscus plumifrons) from Central America, reaching a length of 80 cm, moves on its hind legs at such a speed that it can run not only on land, but also on water.

Many lizards can make certain sounds. Some of them hiss like snakes (for example, monitor lizards). Others make more varied sounds. These are, first of all, geckos. They emit squeaks, clicks, chirps and the like, using not only the tongue, but also the friction of the scales on the tail. The skink gecko (Tegatoscincus scincus), which lives in the Central Asian republics of our country, has such a “musical” tail.

The largest modern lizard is considered to be the giant Indonesian monitor lizard (Varanus komodoensis) from Komodo Island, which reaches a length of 3 m and weighs up to 120 kg. And the smallest lizard, not exceeding 4 cm in length, is the South American gecko - Spherodactylus elegans.

Lizard food

Most lizards are predators. The size of the prey depends on the size of the lizards themselves. Small and medium-sized lizards feed mainly on various insects, spiders, worms, molluscs and small vertebrates. Larger lizards eat larger prey - fish, amphibians, other lizards and snakes, birds and their eggs, various mammals.

A smaller number of lizards are herbivores. However (just as it was noted in the essay on turtles), many lizards, eating mainly plant food, willingly add food of animal origin to their "menu" and, conversely, predators - plant.

Moreover, in most herbivorous lizards, the young feed on insects for the first time and only eventually switch to the food of their parents. Food specialization among lizards is relatively rare, but nevertheless it occurs, and this must be taken into account. Thus, the nutrition of marine iguanas mainly by one species of algae is of exclusively theoretical and general educational interest, and the narrow food specialization of some roundheads on ants or termites may also be of practical interest to us.

Lizard breeding

Reproduction of lizards (as well as turtles) is not very diverse. During the breeding season, which in countries with a temperate climate and a clearly defined change of seasons falls in the spring, and in tropical regions can be completely acyclic, male lizards arrange mating tournaments and care for females, after which they mate with them. Most lizards lay eggs.

Usually eggs have a thin leathery shell, less often (mainly in geckos) - dense, calcareous. The number of eggs in different species is different and can vary from 1-2 to several dozen. The female lays eggs during the year one or more times, in the most diverse, but always secluded places - in holes, cracks, under stones and snags, in hollows of trees, etc.

Some geckos stick their eggs to the trunks and branches of trees, in places of rock outcrops, etc. In most cases, having laid eggs, the lizards no longer return to them. Only a few among them show concern for offspring. Among our lizards, this is the yellow-bellied lizard (Orhisaurus apodus). Females of this species not only guard the masonry, but also take care of it - periodically turn it over, clean it of debris.

Even for some time after the hatching of young yellowbellies, the females continue to protect them and even give up food.
The ability of some lizards to delay the laying of eggs, waiting for the onset of favorable conditions for this, can also be attributed to one of the forms of care for offspring. So, in a quick lizard, eggs can linger in the oviducts for 20 days. In others, for example, in the viviparous lizard (Lacerta vivipara), up to hatching. These are different stages of one process - ovoviviparity. But some species of lizards (most often skinks) also have a true live birth, when the fibrous shell of the egg is reduced and part of the oviduct comes into contact with the chorion - that is, a kind of placenta is formed, with the help of which the embryo is nourished by the mother's body.

One of the reasons for live births is the cold climate, so the percentage of live-bearing species increases as you move north and into the mountains. Interestingly, even lizards of the same species, depending on the altitude above sea level, can either lay eggs or give birth to live young. For example, Tibetan roundheads lay eggs at an altitude of 2 thousand meters above sea level, and at an altitude of 4 thousand meters they are viviparous.

Finishing the conversation about the reproductive biology of lizards, it is advisable to mention the so-called parthenogenetic reproduction, which is characteristic of some of them. At the same time, the species, as a rule, does not have males as such, females lay unfertilized eggs, from which, nevertheless, completely normal young ones hatch.

Parthenogenetic lizards in our country include the Armenian (Lacerta armeniaca), white-bellied (L. unisexualis), Dahl's (L. dah1y) and Rostombekov's (L. rostombekovi) lizards.

Life span of lizards. For many small species, it is small, only 2-5 years, and sometimes even 1 year. But large lizards, primarily monitor lizards, can live up to 50-70 years in captivity.

• Lizards (Lacertilia, formerly Sauria) are a suborder of the scaly order. The suborder of lizards includes all those species that do not belong to the other two suborders of scaly - and two-legged.

• Lizards are widely distributed throughout the world. They are found on all continents except Antarctica.

• These are, as a rule, small animals with well-developed limbs.

• About 3800 modern species of lizards are known, which are united in 20 families.

• The smallest species of lizard, the round-toed lizard from the West Indies, has a length of only 33 mm and weighs about 1 g, and the largest is the Komodo lizard from Indonesia, which, with a mass of 135 kg, can reach 3 m in length.

• Despite the widespread belief that many lizards are poisonous, there are only two such species - the escorpion from Mexico and the related waistcoat from the southwestern United States.

• Most lizards are predators.

• Species of small and medium size feed mainly on various:,.

• Large predatory lizards (tegu, monitor lizards) attack small vertebrates: other lizards, snakes, and small mammals, and also eat bird eggs and.

• Moloch lizard eats only.

• Some large dragon, iguana and skink lizards are completely or almost completely herbivorous. Such species eat leaves, young shoots, fruits and flowers.

• In addition to insects, Madagascar day geckos willingly eat the nectar and pollen of flowers and the pulp of juicy ripe ones.

• Lizards have been living on Earth for hundreds of millions of years. The oldest fossil lizard, called Lizzie's lizard, lived about 340 million years ago. She was found in Scotland in March 1988.

• Some extinct species of lizards were huge. Such a species of lizard as Megalania, which lived in Australia about 1 million years ago, reached a length of about 6 m.

• The shoulder and femur bones of lizards are parallel to the surface of the earth. Therefore, when moving, the body sags and adjoins the ground with its back - it crawls, which gave the name to the class - Reptiles.

• The eyes of most lizards are protected by movable opaque eyelids. They also have a transparent nictitating membrane - the third eyelid, with which the surface of the eye is moistened.

• Gecko lizards do not have eyelids, so they are forced to periodically wet a special transparent membrane in front of their eyes with their tongue.

• In the recess behind the eyes is the tympanic membrane, followed by the middle and inner ear in the bones of the skull. The lizard hears very well. The organ of touch and taste is a long, thin, forked tongue at the end, which the lizard often protrudes from its mouth.

• The scaly cover of the body protects against water loss and mechanical damage, but interferes with growth, and therefore the lizard molts several times during the summer, shedding its skin in parts.

• What DEFINITELY distinguishes all lizards from snakes? If we talk about limbs, which snakes do not have, then there are also legless lizards. Most lizards have visible openings of the external auditory meatus, which snakes do not have, the eyes of lizards, as a rule, are equipped with movable separate eyelids, while in snakes the eyelids have grown together, forming transparent "lenses" in front of the eyes. However, some lizards do not have these features. Therefore, it is more reliable to focus on the features of the internal structure. For example, all lizards, even legless ones, retain at least the rudiments of the sternum and shoulder girdle (the skeletal support of the forelimbs); in snakes, both are completely absent.

• In diurnal lizards, color vision is a rarity in the animal world.

• Many species of lizards are able to shed part of their tail (autotomy). The lizard has a lot of enemies, but only nimble legs and a tail can protect it, with which it can, having assessed the measure of danger, part. The enemy sees a wriggling tail, this distracts his attention, and the animal has not been around for a long time. If a person grabbed the tail, then the tail remains in his fingers. In a number of species capable of autotomy, the tail is very brightly colored, and the lizard itself is much more modest in color, which allows it to quickly hide. After some time, the tail is restored, but in a shortened form. During an autotomy, special muscles compress the blood vessels in the tail, and there is almost no bleeding.

• A lizard without a tail is no longer so fast and nimble, it can lose its ability to reproduce, climbs and runs poorly due to the lack of a “rudder”. In many lizards, the tail serves to accumulate fat and nutrients, which means that all their energy is concentrated in the tail. The animal after its detachment may die from exhaustion. Therefore, the lizard that escapes often tries to find its tail and eat it in order to restore lost strength. There is no complete recovery. The new tail is always worse than the original. It has poor flexibility, shorter length and less dexterous movements.

• Sometimes the tail of a lizard does not come off completely and is gradually restored. But the separation plane is damaged, which gives impetus to the formation of a new tail. This is how a lizard with two tails appears.

• In many climbing forms, such as geckos, anoles and some skinks, the lower surface of the fingers is expanded into a pad covered with bristles - hair-like branched outgrowths of the outer layer of the skin. These bristles catch on the slightest irregularities in the substrate, which allows the animal to move along a vertical surface and even upside down.

• Most often, lizards live in pairs. For wintering and at night they hide in minks, under stones and in other places.

• Most lizards lay eggs. Lizard eggs have a thin leathery shell, less often, as a rule, in geckos - calcareous, dense. In different species, the number of eggs can vary from 1-2 to several dozen.

• They always lay their eggs in the most secluded places - in cracks, under snags, etc.

• Some geckos stick their eggs to tree trunks and branches, on rocks.

• As a rule, having laid eggs, lizards do not return to them.

• Only a few species, for example, female yellowbellies, guard the clutch and take care of it, and after the appearance of young yellowbellies, they continue to protect them and even feed them.

• A smaller number of lizards are ovoviviparous. Their eggs, devoid of a dense shell, develop inside the mother's body, and the cubs are born alive, freeing themselves from the thin film that dresses them while still in the oviducts or immediately after birth.

• Real live birth has been established only in the American night lizards of xanthusia and in some skinks.

• Live birth during reproduction is usually associated with harsh living conditions, for example, living in the far north or high in the mountains.

• The largest lizard was a monitor lizard exhibited in 1937 at the St. Louis Zoo, Missouri, USA. Its length was 3.10 m, and its weight was 166 kg.

• The longest lizard is the thin-bodied Salvador monitor lizard, or musk lizard (Varanus salvadorii), from Papua New Guinea. It, according to accurate measurements, reaches a length of 4.75 m, but approximately 70% of its total length falls on the tail.

• The fastest lizard is the iguana. The highest speed of movement on land - 34.9 km / h - was recorded in the black iguana (Ctenosaura), which lives in Costa Rica.

• The longest-lived is the fragile lizard. A male brittle lizard (Anguis fragilis) lived in the Zoological Museum of Copenhagen, Denmark, for over 54 years, from 1892 to 1946.

• The toad lizard belongs to the family of iguanas that live in the deserts of America. Therefore, the color of the lizards is either sand or stone, so that it is easy to disguise. Toad-shaped lizards live in open areas; over the years of their existence, they have developed many methods of defense. First of all, they will try to freeze in place, hoping that the camouflage coloration will hide them from the predator, then they will jerk. If you can’t hide, the lizard starts to attack, first it stretches out on its paws and swells up like a toad, this is where its name comes from, its size increases by 2 times, but if this doesn’t scare the enemy away, the lizard goes to extreme measures: shoots blood from the eyes, aiming at the muzzle of a predator. Her blood contains poisonous and toxic substances, which makes the predator retreat.

• Lizard two-headed short-tailed skink

A lizard is an animal that belongs to the class of reptiles (reptiles). To date, almost 6,000 species are known. Representatives of families can be very different, some rare species are listed in the Red Book. Both reptiles with legs and some legless forms are called lizards. Reptiles can be vegetarians and eat animal food. Some varieties are suitable for keeping at home.

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Description

Unlike snakes, these reptiles have divided eyelids. Their body is elastic, elongated, ends in a long tail. Paws are proportional, clawed.

According to the general characteristics, the body is covered with keratinized scales, which change several times a year. The tongue can have a different shape, it is usually movable and extends from the mouth. It is with them that lizards catch prey. On both sides of the head are the organs of hearing, which are covered by eardrums.

real lizard

The most common reptile is the real lizard. Her body length is 40 cm.

Teeth are used to tear and grind food. Monitor lizards cut their prey with them.

The only venomous species of lizard is the gila-tooth.



Reptiles live on every continent except Antarctica. Representatives familiar to Russia - real lizards - live almost everywhere. All species move on different surfaces, firmly clinging to irregularities. Rock lizards are excellent jumpers, the height of their jump reaches 4 m.



Tail

Lizards are capable of autotomy, which is used in case of danger: muscle contraction allows you to break the cartilaginous formations of the vertebrae and discard part of the tail, narrowing the blood vessels, while losing blood almost never happens. This distracts the enemy, and the animal avoids the attack.

The tail of the reptile is quickly restored in a shortened form. Sometimes not one, but several grows back.



Color

Lizards have a color that combines green, white, gray and brown. The species that live in the desert exactly repeat the shade of the surrounding area. This is their defense mechanism.

Desert species are able to change body color. These include calot - a reptile with a red head. Among reptiles there are albinos - these are white lizards, devoid of pigment.



The giant lizard has a black and yellow color.



giant lizard

Salamanders are black with yellow spots.



Salamander

Geckos have special colors. Some of them are pink with a blue tail.





Floor

There are a number of signs that allow you to roughly determine gender. It is possible to distinguish a male from a femaleonly in adulthood, as sexual dimorphism developslate.

Male individuals of some species, according to the description, have a crest on the back and head, large pores on the hips. Another feature of the male is the spurs on the paws.

The sex of individual species can be recognized by the throat "bags", preanal scutes and enlarged scales behind the cloaca.

However, only a blood test for testosterone levels can accurately distinguish a male from a female. They make it at the vet.

Varieties

Lizard species are divided into 6 infraorders, which consist of 37 families.

Each of them has its own characteristics.

Skinks

The order includes 7 families with the following names:

• real lizards;
• night lizards;
• herrosaurus;
• skink;
• teiids;
• belttails;
• hymnophthalmids.



Large Herrosaur

iguanas

The order includes 14 families. Some of the representatives of these lizards are real iguanas. These are large reptiles that can reach a length of 2 m. They live mainly in tropical forests.

A prominent representative of the detachment is also a chameleon that inhabits Africa, Madagascar, the countries of the East, the USA. Its peculiarity lies in the ability to change skin color depending on the environment.



Chameleon

In the forests of Cameroon, there is a four-horned chameleon, which got its name because of the characteristic outgrowths on its head. In males, only three "horns" can be developed; in females, they usually do not have them.

geckos

The order consists of 7 families.

Its representative can be called a scalefoot, which lives in Australia.



Scalelegs

Fusiform

The order includes 2 superfamilies and 5 families.

These include monitor lizards, earless monitor lizards, fusiform, legless, xenosaurs.

Large xenosaurus

worm-like

The detachment consists of 2 genera and a family of worm-like lizards, which outwardly resemble worms.

They inhabit Indonesia, China, New Guinea, Philippines.



worm lizard

monitor lizards

The order includes several families, which consist of the largest lizards.

Typical representatives are monitor lizard and gilatooth, which are found in the United States and Mexico.



komodo dragon

Suborder lizards

The order includes the superfamily Shinisaurus.

It includes one species, the crocodile shinizaurus.



Crocodile shinizaurus

record holders

Of the currently existing representatives of lizards, the largest is the Komodo monitor lizard. Some individuals have huge dimensions, reaching three meters in length and a weight of 85 kg in adulthood. A lizard weighing 91.7 kg is listed in the Guinness Book of Records. These reptiles eat small animals, but can also attack larger prey. The Komodo dragon feeds on wild boars, wild goats, and cattle.

The smallest lizards in the world are the Haraguan sphero and the Virginian round-toed gecko. Their dimensions do not exceed 19 mm, weight - 0.2 g.

home views

Various geckos are especially popular with owners.



Pink with gray tail hemiteconix

If you need a calm pet for children, it is better to havegemiteconyx. They have different colors depending on the breed. Their tail accumulates nutrients, which they use as a reserve in the absence of food. Because of this, the tail looks gray, while the body is most often pink. This is a reptile with a very expressive look.



Felzuma

If you want to keep at homethe animal is more active, you can choose a felsum. She has a beautiful emerald color. It can be observed during daylight hours.

At home, they also contain varieties of agamas. The most popular of them are bearded and woody. The first got its name due to the cervical bag, which, when frightened or during the mating season, stretches and darkens. Tree, or black-throated agama is also able to change skin tone. Such pets are reluctant to make contact with the owner and prefer to hide.



Many lizards eat insects. They prefer various crickets, mealworms, raw eggs or pieces of meat, a mixture of chopped boiled chicken, carrots and lettuce.

Supplement food with supplements of vitamins and minerals. In a terrarium for home maintenance, there must be water. If the pet refuses food, but drinks, there is no reason for concern: the lizard simply reduced its activity and did not get hungry.

reproduction

The mating season is in spring and summer. Large species breed once a season, small ones - several times a year. Males are in conflict, approaching each other from the side, trying to look bigger. The small one surrenders without a fight and retreats.

If the males are of the same size, a fight ensues between them, during which they use their teeth. The winner gets the right to the female. In some species, a violation in the sex ratio leads to parthenogenesis - females lay eggs without the participation of males. In lizards, there are 2 types of reproduction: live birth and laying eggs.

Females of small reptiles lay no more than 4 eggs, large ones - up to 18. The mass of one varies from 4 to 200 g. The size of a round-toed gecko egg is no more than 6 mm in diameter. In the monitor lizard, it reaches 10 cm in length.

The laying of females is buried in the ground, hidden in burrows. The incubation period lasts from 3 weeks to one and a half months. It depends on the climate. Having hatched, the cubs begin an independent life.

Pregnancy lasts 3 months, the embryos of northern species hibernate in the womb. Their life span does not exceed 5 years.

General characteristics of the lizard suborder (SAURIA)

About 3,300 species of reptiles of various shapes and sizes (from 3.5 cm to 4 m; weight up to 150 kg). Some are legless. Ways of movement - from swimming (marine iguanas) to gliding (flying dragon). Food is varied - from small invertebrates to wild pigs and deer (giant monitor lizard). The skin is covered with horny scales. Many are capable of autotomy (tail drop). Well-developed vision (many distinguish colors), hearing (some make sounds), touch, parietal eye.

• · Gecko family - 600 species from 3.5 to 35 cm long. They inhabit tropical and subtropical regions. They lead a nocturnal lifestyle. The fingers are equipped with devices that allow geckos to stay on sheer vertical surfaces.
• · iguana family - 700 species from 10 cm to 2 m long. They inhabit the western hemisphere from southern Canada to southern Argentina. In arboreal forms, the body is laterally compressed, while in terrestrial forms, it is flattened in the dorso-ventral direction. Marine iguanas are semi-aquatic.
• · Agama family - about 300 species, close to iguanas, occupying ecological niches in Eurasia, Africa and Asia, similar to those of iguanas in America. They lead an arboreal lifestyle, inhabiting rocks, steppes and deserts. Representatives: steppe, Caucasian agamas, roundheads.
• · a family of real lizards - about 170 species distributed in Europe, Asia and Africa. In our region there are nimble and viviparous lizards.
• · spindle family - 80 species of legless or limbless lizards found on all continents. We meet yellowbell and spindle.
• · monitor lizard family - 30 species of the largest modern lizards. Distributed in Africa, Asia, the Malay Archipelago, Australia. From small (20 cm) to giant (4 m) monitor lizards. The gray monitor lizard and the giant monitor lizard occupy the ecological niche of large predatory animals that are absent in these habitats.

Lizards are the most numerous and widespread group of modern reptiles. The appearance of lizards is extremely diverse. Their head, body, legs and tail may be modified to some extent and deviate considerably from the usual type familiar to everyone. In some species, the body is noticeably compressed from the sides, in others it is valky or flattened from top to bottom, in others it is cylindrically shortened or elongated, like in snakes, from which some lizards are almost indistinguishable in appearance. Most species have two pairs of developed five-fingered limbs, but in some cases only the front or back pair of legs is preserved, and the number of fingers can be reduced to four, three, two and one, or they are completely absent. Most lizards are characterized by incomplete ossification of the anterior part of the skull, the presence of an sometimes incompletely closed upper temporal arch, a strong fusion of the upper jaws with the rest of the cranial bones, and the presence of special columnar bones connecting the roof of the skull to its base. The jaws of lizards are equipped, as a rule, with well-developed single-apex or multi-apex teeth, which are attached from the inside (pleurodont) or to the outer edge (acrodont teeth). Often there are also teeth on the palatine, pterygoid, and some other bones. Often they are differentiated into false canines, incisors and molars.

The language of lizards is extremely diverse in structure, form, and partly in the function it performs. Wide, fleshy and relatively inactive in geckos and agamas, it is strongly elongated, deeply forked, very mobile and able to be drawn into a special vagina in monitor lizards. The bifurcation of the tongue observed in many species, combined with its high mobility, is associated, in addition to touch, also with the function of the Jacobson organ that opens inside the mouth. A short and thick tongue is often used when capturing prey, and in chameleons it is thrown far from the mouth for this. The skin of lizards is covered with horny scales, the nature and location of which varies greatly, which is of decisive importance for taxonomy. In many species, large scales located on the head and other parts of the body increase to the size of scutes, each of which receives a special name. Often on the head and body there are tubercles, spikes, horns, ridges or other horny outgrowths formed by modified scales and sometimes reaching considerable sizes in males. Some groups of lizards are characterized by the occurrence under the scales of the body and head of special bone plates - osteoderms, which, articulated with each other, can form a continuous bone shell. In all species, the upper horny layer of the scales is shed during periodic molts and is replaced by a new one. The shape and size of the tail is very diverse. As a rule, it gradually becomes thinner towards the end and differs in considerable length, noticeably exceeding the body and head combined. However, in some cases it is shortened like a blunt cone, thickened at the end in the form of a radish, flattened spatulately, or has another unusual shape. More often oval or round in cross section, it is often compressed in a horizontal or vertical plane in the form of an oar. Finally, in a number of lizards, the tail is tenacious or capable of twisting like a spiral. Many lizards have the ability to autotomy. The fracture occurs along a special non-ossified layer across one of the vertebrae, and not between them, where the connection is stronger. Soon the tail grows back, but 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. Often the torn tail is not completely separated, but a new one nevertheless grows, resulting in the appearance of two-tailed and multi-tailed individuals. It is interesting that in many cases the scales of the reconstructed tail differ from the normal one, and moreover, it has features of more ancient species. The dry skin of lizards is devoid of glands, but some roundheads (Phrynocephalus) have real skin glands on their backs, the function of which is not entirely clear. In representatives of a number of families, on the lower surface of the thighs, the so-called femoral pores are arranged in rows - special iron-like formations, from which columns of hardened secretion protrude in males during the breeding season. In other species, such formations are located in front of the anus or on its sides, respectively, called the anal and inguinal pores.

The smallest known lizards (some geckos) reach a length of only 3.5-4 cm, while the largest monitor lizards grow at least up to 3 m, weighing 150 kg. As a rule, males are larger than females, but in some cases, females, on the contrary, are noticeably larger than males. The eyes of lizards are in most cases well developed and protected by eyelids, of which only the lower one is movable, while the upper one is greatly shortened and usually loses its mobility. Along with this, in many species, the moving eyelids are replaced by a solid transparent shell covering the eye like a watch glass, like in snakes. On the example of a number of species from various systematic groups, it is easy to trace the gradual stages of the transition from opaque separate eyelids to the appearance of a first transparent window in the still mobile lower eyelid and further to the complete fusion of the lower eyelid with the upper one and the formation of an already immovable window in it. Such fused eyelids are present in most nocturnal lizards - geckos, a number of legless and burrowing species, as well as in some skinks and other lizards, as well as a diurnal and nocturnal lifestyle. Nocturnal lizards, as a rule, have significantly enlarged eyes with a pupil in the form of a vertical slit with straight or sawtooth cut edges. In the retina of the eyes of diurnal lizards there are special elements of color vision - cones, thanks to which they are able to distinguish all colors of the solar spectrum. In most nocturnal species, light-sensitive elements are represented by rods, and the perception of colors is not available to them. As a rule, lizards have good hearing. The tympanic membrane may be located openly on the sides of the head, hidden under the scales of the body, or may be completely overgrown with skin, so that the external auditory opening disappears. Sometimes it, together with the tympanic cavity, is reduced, and the animal is able to perceive sound only in a seismic way, that is, by pressing its whole body against the substrate. Most lizards emit only a dull hiss or snort. More or less loud sounds - squeaking, clicking, chirping or croaking - are capable of producing different geckos, which is achieved with the help of a tongue or by rubbing horny scales against each other. In addition to geckos, some sand lizards (Psammodromus) can also “squeal” quite loudly. The sense of smell is less developed than other senses, but some lizards may well find prey by smell. The nostrils of many, especially desert species, are closed with special valves that prevent sand from entering the nasal cavity. Some lizards have a well-developed sense of taste and willingly drink, for example, sugar syrup, choosing it among tasteless solutions. However, their taste sensitivity to bitter substances is negligible. Many lizards have tactile hairs formed from keratinized cells of the upper layer of the skin and regularly located along the edges of individual scales. In different places of the trunk and head, in addition, special tactile spots are often located, on which sensitive cells are concentrated. Many lizards have a so-called third, or parietal, eye, usually noticeable as a small light spot in the center of one of the scutes covering the back of the head. In its structure, it somewhat resembles an ordinary eye and can perceive certain light stimuli, transmitting them along a special nerve to the brain. The coloration of lizards is extremely diverse and, as a rule, harmonizes well with the environment. In species that live in deserts, light, sandy tones predominate; lizards living on dark rocks often have a brown, almost black color, and lizards living on tree trunks and branches are dotted with brown and brown spots resembling bark and moss. Many woody species are colored in the color of green foliage. A similar coloration is characteristic of a number of agamas, iguanas and geckos. The general coloration of the body largely depends on the nature of the pattern, which can be composed of individual symmetrically located spots, longitudinal or transverse stripes and rings, rounded eyes, or spots and specks randomly scattered throughout the body. In combination with the color of the main background of the body, these patterns further camouflage the animal in the surrounding area, hiding it from enemies. Diurnal species are characterized by very bright reds, blues and yellows, while nocturnal species are usually more uniformly colored. The coloration of some lizards varies significantly depending on sex and age, with males and juveniles usually more brightly colored. A number of species tend to quickly change color under the influence of changes in the environment or under the influence of internal states - excitement, fright, hunger, etc. This ability is inherent in some iguanas, geckos, agamas and other lizards.

Distribution and lifestyle.

The maximum number of lizard species lives in the tropical and subtropical zones of the globe, there are fewer of them in countries with a temperate climate, and the farther to the north and south, the more their number is declining. For example, only one species reaches the Arctic Circle - the viviparous lizard. The life of some lizards is closely connected with water, and although there are no real marine forms among lizards, one of them, the Galapagos iguana (Amblyrhynchus crislatus), penetrates the coastal waters of the ocean. In the mountains, lizards rise to the level of eternal snows, living at an altitude of up to 5000 m above sea level. Under specific environmental conditions, lizards acquire the corresponding features of specialization. So, in desert forms, special horny scallops develop on the sides of the fingers - sandy skis, which allow you to quickly move along the loose surface of the sand and dig holes. Lizards living in trees and rocks usually have long and prehensile limbs with sharp claws and often a prehensile tail that aids in climbing. Many geckos that spend their entire lives on vertical surfaces have special extensions on the underside of their fingers with tiny tenacious hairs that can attach to the substrate. In many limbless and burrowing lizards, the body is elongated serpentine. Such adaptations to certain living conditions in lizards are extremely different, and almost always they concern not only the features of the external structure or anatomy, but also affect many important physiological functions of the body associated with nutrition, reproduction, water metabolism, rhythm of activity, thermoregulation, etc. e. The optimal environmental temperature, most favorable for the life of lizards, lies in the range of 26--42 ° C, and in tropical and desert species it is higher than in the inhabitants of the temperate zone, and in nocturnal forms, as a rule, lower than in daytime . When the temperature rises above the optimum, the lizards hide in the shade, and when the limit temperatures are established for a long time, they completely stop their activity, falling into the state of the so-called summer hibernation. The latter is often observed in desert and arid regions in the south. In temperate latitudes, lizards leave for wintering in autumn, which in different species lasts from 1.5-2 to 7 months a year. Often they overwinter several tens or even hundreds of individuals in one shelter.

In lizards, the transition from real crawling on the belly to a gradual lifting of the body above the substrate and, finally, to movement with the torso raised high on the legs is clearly traced. The inhabitants of open spaces tend to move at a fast trot, and many of them switch to running on two legs, which is observed not only in exotic, but also in some species of our fauna. Curiously, the South American iguana Basiliscus americanus can even run short distances in this state through the water, slapping its surface with its hind legs. The ability to run fast is combined, as a rule, with the presence of a long tail, which plays the role of a balancer, as well as a rudder for turns on the run. Many geckos move in very short dashes, staying in one place for a long time. Arboreal species develop the ability to climb, which often involves a prehensile tail. Finally, some specialized forms, such as flying dragons (Draco), are capable of gliding flight due to skin folds on the sides of the body, supported by highly elongated ribs. Many lizards jump well, grabbing prey on the fly. Some desert species have adapted to "swimming" in the thickness of the sand, in which they spend most of their lives.

Most lizards are predators, feeding on all kinds of animals that they are able to grab and overpower. The main food of small and medium-sized species are insects, spiders, worms, molluscs and other invertebrates. Larger lizards eat small vertebrates - rodents, birds and their eggs, frogs, snakes, other lizards, and carrion. A smaller number of lizards are herbivores. Their food consists of fruits, seeds and succulent parts of plants. The lizards slowly sneak up on the prey and then grab it in the final throw. As a rule, the prey is eaten whole, but may be preliminarily torn apart by the jaws. Like other reptiles, lizards are able to remain without food for a long time, consuming the nutrient reserves deposited in the fat bodies located in the body cavity. In many species, in particular in geckos, fat is also deposited in the tail, the size of which is greatly increased. Lizards drink water by licking it with their tongue or scooping it up with their lower jaw. Desert species are content with water in the body of the prey they eat, and in some of them it can accumulate in special sac-like formations located in the abdominal cavity. In desert iguanas of the genus Sauromalus, on the sides of the body under the skin, there are special lymphatic sacs filled with a gelatinous fluid, which largely consists of water accumulated during rains and then slowly consumed during a long drought.

The lifespan of lizards varies greatly. In many relatively small species, it does not exceed 1-3 years, while large iguanas and monitor lizards live for 50-70 years or more. Some lizards survived for 20 - 30 and even 50 years in captivity. Most lizards benefit by eating a significant amount of harmful insects and invertebrates. The meat of some large species is quite edible, which is why they are often the object of a special trade, and the skin of these reptiles is also used by humans. In a number of countries, the capture and extermination of some lizards is prohibited by law. Currently, about 4000 species of various lizards are known, usually united in 20 families and almost 390 genera.