Characteristics of the lizard. Names and features of different types of lizards
Lizards.
Lizards and snakes form the order Squamate (the body of these reptiles is covered with small scales).
There is such a variety of lizards in nature that for simplicity we can say that “lizards” are all scaly ones, except snakes.
Paleontologists have found the remains of the oldest herbivorous lizard in Japan. The age of the discovered jaw and fragments of its skull is 130 million years! The lizard reached 25-30 cm in length.
Most lizards are predators. In nature, small and medium-sized lizards feed mainly on various insects, worms, and small vertebrates. Larger lizards eat larger prey - fish, amphibians, snakes or other lizards, birds and their eggs, and various mammals.
By the way, lizards, even as they age, retain their teeth, which fall out and are replaced by new ones throughout their lives.
Reproduction of lizards.
Most lizards lay eggs. Lizard eggs usually have a thin, leathery shell. The number of eggs in different species can vary from 1-2 to several dozen. Females always lay eggs in the most secluded places - in cracks, under snags, etc. As a rule, after laying eggs, lizards do not return to them.The smallest of the lizards is the round-toed gecko from India, only 33 mm long and weighing about 1 gram.
And the largest is the Komodo dragon from Indonesia, which can reach 3 m in length and weigh 135 kg.
Despite the widespread belief that many lizards are poisonous, there are only two such species and they live in the southwestern United States and Mexico. Their poison is dangerous to humans, but non-lethal. On the picture - POISON TOOTH HOUSING.
The scales of lizards can be both small and large; they can be located close to each other (like tiles) or overlapping (like tiles). Sometimes they are transformed into spines or ridges. All lizards molt periodically, shedding their outer layer of skin.
In many climbing forms, such as anoles, geckos and some skinks, the lower surface of the fingers is expanded into a pad covered with setae - 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.
There are lizards that are completely legless! Only a specialist can distinguish such a lizard from a snake - they have different skeletal structures. So, if you encounter an unfamiliar legless scaly creature, it’s better to play it safe and don’t pick up the “lizard” in case it turns out to be a real snake!
Lizards are attacked by almost all animals that can grab and defeat them. These are snakes, birds of prey, mammals and humans. Lizards have several methods of protecting themselves from predators. If you get too close to some lizards, they will take on a threatening pose. For example, the Australian frilled lizard suddenly opens its mouth and raises a wide, bright collar formed by a fold of skin on its neck. Helps! Obviously, the effect of surprise plays a role in scaring off enemies.
MOLOH, a bizarre-looking lizard that lives in the sandy deserts of the south and west of Australia, looks very inedible.
AGAMA FLYING DRAGON is capable of gliding, running away from a predator, spreading the leathery folds along the sides of the body, like a flying squirrel, supported by long false ribs.
LATEST NEWS!
University of Michigan zoologists have penetrated the main secret of lizards
A precise answer has been given to the intriguing question: why do these nimble creatures cast off their tails? Previously, everyone thought that in this way reptiles pay off predators, throw them a distracting piece of meat in the hope of saving everything else.
Now it turns out that by unfastening their tail, lizards protect themselves from snake bites. Research took place in Greece. On islands infested with vipers, scientists have counted many more tailless lizards than in places where there are no snakes. Long-term observations have shown that the deliberate loss of part of the flesh does not bring salvation in fights with birds and animals, but is unusually effective against snakes. In case of a bite, the poison from the tail does not spread throughout the body.
Until the body recovers, the lizard suffers many inconveniences: it is difficult to move, growth slows down. But most importantly, relatives look with disdain and refuse to continue the family line with the disabled person.
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 differ greatly; some rare species are listed in the Red Book. Lizards are both reptiles with legs and some legless forms. Reptiles can be vegetarians and eat animal foods. Some varieties are suitable for keeping at home.
- real lizards;
- night lizards;
- Gerrosaurs;
- skinks;
- Teiids;
- belttails;
- Gymophthalmides.
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Description
Unlike snakes, these reptiles have separated eyelids. Their body is elastic, elongated, ending 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 different shapes; it is usually mobile and extends out of the mouth. It is with them that lizards catch prey. On both sides of the head are the hearing organs, which are covered by the eardrums.
Real lizard
The most common reptile is the true lizard. Her body length is 40 cm.
Teeth are used for tearing and grinding food. Monitor lizards use them to cut up their prey.
The only poisonous species of lizard is the poison tooth.
Reptiles live on all continents except Antarctica. Representatives familiar to Russia - real lizards - live almost everywhere. All species move on different surfaces, clinging tightly to uneven surfaces. Rock lizards are excellent jumpers, their jump height 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, resulting in blood loss almost never happens. This distracts the enemy, and the animal avoids the attack.
The reptile's tail quickly recovers in a shortened form. Sometimes not one, but several grow back.
Color
Lizards have a color that combines green, white, gray and brown. Species that live in the desert exactly repeat the hue of the surrounding area. This is their defense mechanism.
Desert species are capable of changing body color. These include the calot, a reptile with a red head. Among reptiles, there are albinos - these are white lizards lacking pigment.
The gigantic lizard is black and yellow in 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. You can distinguish a male from a femaleonly in adulthood, as sexual dimorphism developslate.
Males of some species are described as having a ridge on their back and head and large pores on their thighs. Another feature of the male is spurs on his paws.
The sex of certain species can be determined by the throat “bags”, preanal scutes and enlarged scales behind the cloaca.
However, only a blood test for testosterone levels will help to accurately distinguish a male from a female. It is done at the veterinary clinic.
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:
Large Gerrosaurus
Iguanas
The order consists of 14 families. Some of the representatives of these lizards are true iguanas. These are large reptiles that can reach a length of 2 m. They live mainly in tropical forests.
A striking representative of the order is also the chameleon, which inhabits Africa, Madagascar, Eastern countries, and 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 growths on its head. Males can only develop three “horns”; females usually do not have them.
Gecko-like
The order consists of 7 families.
Its representative can be called the scalefish, which lives in Australia.
Scalelegs
Fusiformes
The order includes 2 superfamilies and 5 families.
These include monitor lizards, earless monitor lizards, spindle monitors, legless monitor lizards, and xenosaurs.
Large xenosaur
Vermiformes
The order consists of 2 genera and a family of worm-like lizards, which externally resemble worms.
They inhabit Indonesia, China, New Guinea, and the Philippines.
Worm-like lizard
Monitor lizards
The order includes several families, which consist of the largest lizards.
Typical representatives are the monitor lizard and the poisonous tooth, which are found in the USA and Mexico.
Komodo dragon
Lizard suborder
The order includes the superfamily Shinisaurus.
It includes one species, the crocodile shinisaurus.
Crocodile Shinisaurus
Record breakers
Of the existing representatives of lizards, the largest is the Komodo dragon. Some individuals have enormous dimensions, reaching three meters in length and a weight of 85 kg in adulthood. A monitor 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 Haraguana sphero and the Virginia round-toed gecko. Their dimensions do not exceed 19 mm, weight - 0.2 g.
Domestic species
Various geckos are especially popular among owners.
Pink with gray tail hemiteconix
If you need a calm pet for children, it is better to gethemiteconyx. They have different colors depending on the breed. Their tail stores nutrients, which they use as a reserve when food is lacking. Because of this, the tail appears gray, while the body is most often pink. This is a reptile with a very expressive look.
Felzuma
If you want to keep it at homeIf the animal is more active, you can choose felsuma. She has a beautiful emerald color. You can watch her during daylight hours.
At home they also keep varieties of agamas. The most popular of them are bearded and woody. The first received its name due to the neck sac, which, when frightened or during the mating season, stretches and darkens. The tree or black-throated agama is also capable of changing skin tone. Such pets are reluctant to make contact with the owner and prefer to hide.
Many lizards feed on insects. They prefer various crickets, mealworms, and will not refuse raw eggs or pieces of meat, a mixture of chopped boiled chicken, carrots and lettuce.
The food is supplemented with vitamins and minerals. A terrarium for home maintenance must have water. If the pet refuses food but drinks, there is no reason to worry: the lizard has simply decreased its activity and is not hungry.
Reproduction
The mating season occurs in spring and summer. Large species reproduce once a season, small ones - several times a year. Males conflict, approach each other from the side, trying to look bigger. The small one gives up without a fight and retreats.
If the males are 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, an imbalance in the sex ratio leads to parthenogenesis - females lay eggs without the participation of males. Lizards have two types of reproduction: viviparity and oviposition.
Females of small reptiles lay no more than 4 eggs, large ones - up to 18. The weight of one varies from 4 to 200 g. The size of the round-toed gecko egg is no more than 6 mm in diameter. In the monitor lizard it reaches 10 cm in length.
The females bury the clutches in the ground and hide them 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; embryos of northern species overwinter in the womb. Their lifespan does not exceed 5 years.
Lizards belong to the class of reptiles. Their defining characteristics include a long tail, two pairs of legs that extend outward from the body, and scaly skin. Most lizards are cold-blooded animals and depend on environmental conditions to regulate their body temperature. There are many species of lizards distributed throughout the world. Different species of lizards have different distinctive characteristics, which makes them interesting to study. Some of them even look prehistoric or like creatures from science fiction movies!
Gecko currents
Gecko currents ( Gekko gecko listen)) is a species of nocturnal reptiles belonging to the genus Gekko, found in Asia and also on some islands in the Pacific Ocean. The lekko gecko has a robust body, a large head, and strong limbs and jaws compared to other gecko species. This is a large lizard that reaches 30 to 35 centimeters in length. Although the lekki gecko camouflages itself with its surroundings, it is usually greyish in color with red spots. Its body is cylindrical in shape and smooth in texture. Lekka geckos are sexually dimorphic, which is reflected in the brighter color of males than females. They feed on insects and other small ones. Their strong jaws allow them to easily crush the exoskeleton of insects.
Marine iguana
Marine iguana ( Amblyrhynchus cristatu listen)) is a species of lizard found only in the Galapagos Islands of Ecuador, with each island home to marine iguanas of varying sizes and shapes. Recently, their populations have been under threat due to the large number of predators that feed on lizards and their eggs. Marine iguanas are marine reptiles that are often called ugly and disgusting due to their appearance. Contrary to their fierce appearance, marine iguanas are gentle. Their color is mainly black soot. Their long, flattened tail helps them swim, and their flat, sharp claws allow them to cling to rocks in the event of strong currents. Marine iguanas often sneeze to clear salt from their nostrils. In addition to sneezing, they have special glands that secrete excess salt.
Lesser belttail
Lesser belttails ( Cordylus cataphractus) lives in desert and semi-desert areas. They are mainly found along the west coast of South Africa. The lizards were used in the pet trade for a long time until they became endangered. The color of the lesser belttail is either light brown or dark brown, and the lower part of the body is yellow with dark stripes. They are diurnal reptiles that feed on small plants, as well as other types of small lizards and rodents. If the lizard senses danger, it inserts its tail into its mouth to form a spherical shape that allows it to roll. This form exposes the spines on its back, protecting the lesser belttail from predators.
Agama Mwanza
Agama Mwanza ( Agama mwanzae) are found in most sub-Saharan countries. They are usually 13-30 cm long, with males 8-13 cm longer than females. These lizards usually live in small groups with one male as the leader. The dominant male is allowed to breed, while other males cannot mate with females from the group unless they eliminate the dominant male or form their own group. Mwanza agamas feed on insects, reptiles, small mammals and vegetation. They mate during the rainy season. Before mating, the male digs small holes using his snout. After mating, the females lay eggs in the holes. The incubation period takes 8 to 10 weeks.
Komodo dragon
Komodo dragon ( Varanus komodoensis) is the largest known species of lizard. They live on the Indonesian islands of Komodo, Rinca, Flores and Gili Motang. Mature monitor lizards weigh on average 70 kg and are about 3 meters long. Komodo dragons ambush a variety of prey, including birds, invertebrates, small mammals, and in rare cases, humans. Its bite is poisonous. The protein venom they inject when they bite can cause victims to lose consciousness, low blood pressure, muscle paralysis and hypothermia. Komodo dragons breed from May to August, and females lay eggs between August and September.
Moloch
(Moloch horridus) is mainly found in Australian deserts. It grows up to 20 cm and has a lifespan of 15 to 16 years. Its color is usually brown or olive. Moloch camouflages itself in cold weather, changing its skin tone to a darker one. Its body is covered with spines for protection. The lizard also has soft tissue that resembles its head. The tissues are located on the upper part of the neck and serve for protection, in which the spiny dragon hides its real head if it senses danger. Moloch has another amazing survival mechanism in the desert. Its complex skin structure, under the action of capillary force, helps to fuse water into the lizard's mouth. The main diet of the moloch consists of ants.
Arizona snaketooth
Arizona snaketooth ( Heloderma suspectum) is a poisonous species of lizard that lives in desert and rocky areas of Mexico and the United States. These reptiles have flattened triangular heads, which are larger in males than in females. Long, thick and cylindrical body, wider in females. Their diet consists of reptile eggs, birds and rodents. Hunting skills are characterized by a strong sense of smell and hearing. The Arizona Eurasian eagle can hear the vibrations of its prey from afar and smell the scent of buried eggs. The large body and tail are used to store fat and water reserves, which allows them to survive in deserts. Dry and flaky scales prevent excessive loss of water from the lizard's body.
Parson's Chameleon
Parson's Chameleon ( Calumma Parsonii) is the largest chameleon in the world by mass. It is found in Madagascar. The large and triangular head has independently moving eyes. Males have two horny structures directed from the eyes to the nose. Females lay up to fifty eggs, which can incubate for up to 2 years. After hatching, young Parson's chameleons immediately become independent. Due to their unusual appearance, they are imported to other countries for pet keeping. However, most reptiles die during transport. Parson's chameleons are immobile animals that perform minimal movements only for feeding, drinking and mating.
Lobe-tailed gecko
Lobe-tailed gecko ( Ptychozoon kuhli) is found in Asia, especially in India, Indonesia, Southern Thailand and Singapore. They have unusual leathery growths on the sides of their bodies and webbed feet. They feed on crickets, waxworms and mealworms. These are nocturnal reptiles. Males are very territorial and difficult to cage. They camouflage themselves under the bark of trees, which helps them avoid predators. Lobe-tailed geckos live inside trees and jump from branch to branch, especially when they sense danger.
rhinoceros iguana
Rhinoceros Iguana ( Cyclura cornuta) is an endangered species of lizard native to the Caribbean island of Hispaniola. They have a horn-like growth on their face, similar to the horn of a rhinoceros. The length of rhinoceros iguanas is 60-136 cm, and the weight ranges from 4.5 kg to 9 kg. Their color ranges from grayish to dark green and brown. Rhinoceros iguanas have large bodies and heads. Their tail is vertically flattened and quite strong. They are sexually dimorphic, and males are larger than females. After mating, females lay 2 to 34 eggs over 40 days. Their eggs are among the largest of any lizard.
Lizards are a more numerous and ancient group of reptiles from the squamate suborder. Unlike snakes, they have eyelids and limbs. They live everywhere except the Arctic and subarctic zones. In total there are about 3,600 species of lizards. Most of these reptiles live in the tropical and subtropical zones of South America, Australia and southern Asia. Basically, lizards lead a terrestrial lifestyle, feeding on small rodents and insects, and the largest representatives, monitor lizards, hunt large game: rabbits, hares, gazelles, buffalos. There are almost no vegetarians among lizards.
This suborder includes only 6 families: skinks, iguanas, monitor lizards, geckos, spindles, agamidae.
Skinks from lat. Scincidae- a very large group of lizards: 130 genera and 1.5 thousand species.
Most often, representatives of this group are not very large. They have a very smooth horny cover, thanks to the special arrangement of “polished” scales. Underlain by osteoderms. The body and head are disproportionately large compared to the legs. Therefore, skinks move very slowly, but if they need to escape from predators they can develop high speed.
We also observe in skinks laterally compressed conical teeth, slightly curved. In blue-tongued skinks (herbivorous), they are thicker and rounded at the tip.
Most skinks have pale ocher colored scales, but some representatives are colored in a wide variety of colors: red, blue, green, black, pink, turquoise. The blue tongue or fire skink have this range.
The habitat is very diverse. This family lives on all continents except Antarctica. A large variety of species can be found in tropical and subtropical zones. But skinks have successfully spread to the northern regions. They live in: deserts, forests, steppes - in a wide variety of biotopes. The lifestyle is often terrestrial, but dart frogs are also found.
Iguanas Iguaninae- lizards that occupy the second place in size in this suborder. The length of an adult iguana can exceed 2 meters. Now there are 8 genera and 25 species. These creatures have amazingly preserved their prehistoric appearance, which has helped them survive to this day. The most famous representative of this family is the Green iguana. Representatives of this family are some of the most amazing lizards: they have retained the appearance of antiquity and are trainable. Another interesting fact concerns the smallest representatives of iguanas, Basiliscus, which have learned to run on water.
Iguanas are common in Central and South America, the Greater Antilles and Galapagos Islands.
Iguanas lead a mainly arboreal lifestyle. In dense foliage they escape the heat and receive moisture from the air moistened by the foliage. They feed exclusively on plant foods.
Varanus monitor lizards- These are the largest lizards on earth. Includes 70 species.
The largest representative, the Komodo dragon Varanus komodoensis, reaches a length of 3–4 meters and weighs more than 100 kg. Then come the motley, black-toothed, etc. Their length can reach 2 meters, and their weight is from 20 to 30 kg. Monitor lizards, like the knights of the Middle Ages, have powerful armor, like chain mail, and sharp weapons. Their skin, which is covered with splints or enlarged horny shields, acts as armor. The claws act as a sickle. But monitor lizards also invented chemical weapons - a huge amount of microbes and bacteria accumulate in their mouths, to which they are immune. When hunting, it is enough to bite the victim, the infection lasts from several minutes to half an hour, then the body cannot function normally and weakens. After which the monitor lizard finds prey by smell and eats it.
But there are also small monitor lizards, which are even popular for keeping in terrariums. The most famous species are Cape and Emerald. Their weight is several kilograms, and their length is about a meter or a little more. These species are less dangerous and aggressive. Unless they have sharp claws.
All representatives of this family inhabit Africa and Australia, as well as South Asia and the Indonesian islands. As a rule, they lead a terrestrial lifestyle. Sometimes poison dart frogs are also found.
Geckos or clasp-toeds (Gekkonidae)– Geckos or clasp-toed geckos
Interesting group, includes 70 rub. and 700 v. The head is covered with small thickened scutes. The eyes are bulging, very large in size, and there are no eyelids; if necessary, they are moistened with the tongue. Which is very wide and soft, has lumpy specks (so as not to damage the eye membrane). Typically, representatives of this family are nocturnal. During the mating season they are active during the day. Can make various sounds (communication).
There are species from New Zealand that are viviparous.
They received the name “tenacious” for their ability to climb walls and ceilings with the help of special bristles on their paws. They are covered with thousands of microscopic hairs, which allow the animal to climb the walls. But for this ability, geckos gradually decreased in size during evolution and acquired light and soft scales so as not to fall down under the influence of gravity; the weight of geckos is only 15 - 30 grams, and the length with a tail is 20 cm.
Geckos are distributed across all continents except Antarctica. They are more common in tropical and subtropical zones. Geckos are the most popular lizards to keep at home. They are not demanding: they feed on insects and plant foods, temperatures range from 30 degrees during the day and 25 at night, a medium-sized vertical terrarium.
Agamidae – This unique family contains approximately 50 genera and more than 350 species. This group is very peculiar: here we can see dwarfs (round-headed 8 cm) and giants (plated beetle 180 cm). This also includes: huge burrowers, dart frogs, walking, flying and aquatic forms.
Agamas live in Eurasia and also inhabited Africa (not in Madagascar) and Australia. They live in a wide variety of biotopes and quickly adapt to new conditions. Tundras, forests, steppes, wastelands, banks of rivers and lakes, mountain ranges - all this is conquered by these amazing reptiles. But Antarctica and the Arctic zones still remain untouched by them.
The main difference between agamas is the structure of their skin and teeth. Sharp spines can be seen among the horny cover, most often on the neck and back. The teeth are located on the outer rim rather than on the inside of the jaws.
The most amazing representative is the flying dragon Draco. It is 30–40 centimeters long and weighs several grams. The most interesting thing is that he can spread out his ribs like wings and stretch his skin. Starting from a height, it can fly more than 100 meters quite quickly. Thus, the flying dragon holds the record for gliding among reptiles.
Spinids (Anguidae) – more primitive group. 13 genera and 120 species. Habitat: Asia and Europe.
Spindlefish can be either with a full set of limbs or legless (fragile spindle); there is a species in which the legs are represented by small and thin outgrowths. The horny cover is supported by bony plates.
Representatives of this family have two lateral folds. It helps the lizard breathe and push food through. Spindletails have the ability to “unfasten” when the tail falls off, regenerating over time, but will not be the same initially. Some species of this family can be confused with snakes, but they have eyelids and extended ear dimples.
The diet consists of beetles, mice, and molluscs. At the same time, their teeth are dull.
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 lineage 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 out or retract inward like the fingers of a glove. The inverted hemipenises serve for internal fertilization of the female during mating. Lizards and snakes form the order of scaly animals - Squamata (from the 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 lineages of squamates with reduced limbs, make up the suborder Serpentes. The suborder of lizards comprises several highly divergent evolutionary lineages. For simplicity, we can say that “lizards” are all scaly animals, except 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 (like 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 rudiments of the sternum and shoulder girdle (the skeletal support of the forelimbs); Both of these are completely absent in snakes.
Distribution and some species. Lizards are widespread throughout the world. Absent from Antarctica, they are found from the southern tip of other continents to southern 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 elevations below sea level, such as Death Valley in California, to 5500 m above sea level in the Himalayas. Known approx. 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 and weighs 135 kg.
Despite the widespread belief that many lizards are venomous, there are only two such species - the common lizard (Heloderma suspectum) from the southwestern United States and the related escorpion (H. horridum) from Mexico. The oldest fossil remains of lizards date back to the Late Jurassic (ca. 160 million years ago). Some of their extinct species were enormous in size. It is believed that Megalania, which lived in Australia in the Pleistocene (approx. 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 for ca. 85 million years ago. The closest modern relative of lizards and snakes is the rather large tuatara, or tuatara (Sphenodon punctatus), from New Zealand.
Appearance. The background color 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 can be both small and large; they can be located close to each other (like tiles) or overlapping (like tiles). Sometimes they are transformed into spines or ridges. Some lizards, such as skinks, have bony plates called osteoderms inside their horny scales, which give the integument additional strength. All lizards molt periodically, shedding their outer layer of skin. The limbs of lizards are designed 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 setae - 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 (the roof of the oral cavity). The teeth are held on the jaws in two ways: acrodontally, almost completely fused with the bone, usually along its edge and not replaced, or pleurodontally - loosely attached to the inside of the bone and regularly replaced. Agamas, amphisbaenas and chameleons are the only modern lizards with acrodont teeth.
Sense organs. The eyes of lizards are developed differently, depending on the species - from large and well-seeing in diurnal forms to small, degenerate and covered with scales in some burrowing taxa. Most have a movable scaly eyelid (lower eyelid only). Some medium-sized lizards have a transparent “window” on it. In a number of small species it occupies most or the entire area of the eyelid, 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 gaze as a result is unblinking, like that of snakes. Lizards with a movable eyelid have a thin nictitating membrane, or third eyelid, underneath it. This is a transparent film that can move from side to side. Many lizards have retained the parietal “third eye” characteristic of their ancestors, which is not capable of perceiving shape, but distinguishes between light and darkness. It is believed to be sensitive to ultraviolet radiation and helps regulate sun exposure as well as other behaviors. Most lizards have a noticeable opening in the shallow external auditory canal, which ends in the eardrum. These reptiles perceive sound waves with a frequency of 400 to 1500 Hz. Some groups of lizards have lost their auditory opening: it is either covered with 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, worse than the “eared” ones. The Jacobson (vomeronasal) organ is a 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 holes. With its help, lizards can determine the chemical composition of substances that enter their mouths and, more importantly, those in the air that fall on their protruding tongue. Its tip is brought to the Jacobson's organ, the animal "tastes" the air (for example, to the proximity of prey or danger) and reacts accordingly.
Reproduction. Initially, lizards belong to oviparous animals, i.e. lay shell-covered eggs that develop for several weeks outside the mother's body before hatching. However, many groups of lizards have developed ovoviviparity. Their eggs are not covered with a shell, they remain in the female’s oviducts until embryonic development is completed, and the already “hatched” cubs are born. Only the widespread South American skinks of the genus Mabuya can be considered truly viviparous. Their tiny, yolkless eggs develop in the oviducts, likely receiving nutrition from 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, and in skinks and a number of American tropical geckos, there is always only one cub in the brood. 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 to be 10 years or more, and one copperhead, or brittle spindle (Anguis fragilis), reached 54 years of age in captivity.
Enemies and methods of defense. Lizards are attacked by almost all animals that can grab and defeat 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 will take on a threatening pose. For example, the Australian frilled lizard (Chlamydosaurus kingii) suddenly opens its mouth and raises a wide, bright collar formed by a fold of skin on its neck. Obviously, the effect of surprise plays a role in scaring off enemies. If many lizards are grabbed by the tail, they throw it away, leaving the enemy with a wriggling piece of debris 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.
Collier's Encyclopedia. - Open Society. 2000 .
See what "LIZARDS" is in other dictionaries:
- (Saurra), suborder of squamates. Appeared in the Triassic. Ancestors of snakes. The body is ridged, flattened, laterally compressed or cylindrical, of various colors. Skin covered with horny scales. Dl. from 3.5 cm to 4 m (monitor lizards). The front part of the skull is not... ... Biological encyclopedic dictionary
Suborder of reptiles of the order Squamate. The body ranges from a few cm to 3 m or more in length (Komodo dragon), covered with keratinized scales. Most have well-developed limbs. More than 3900 species, on all continents except Antarctica,... ... Big Encyclopedic Dictionary
- (Lacertilia s. Sauria) reptiles with an anus in the form of a transverse slit (Plagiotremata), with a paired copulatory organ, teeth not in meshes; usually equipped with a front girdle and always have a sternum; in most cases with 4 limbs,... ... Encyclopedia of Brockhaus and Efron
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- (Sauria) suborder (or order) of reptiles of the order (or subclass) squamate. Body length from 3.5 cm to 3 m (Komodo dragon). The body is ridged, flattened, laterally compressed or cylindrical. Some have well-developed five-fingered... ... Great Soviet Encyclopedia
Lizards->) and a female. /> Viviparous lizards: male () and female. Viviparous lizards. Lizards, a suborder of the class animals. They are distinguished by the presence of limbs () and movable eyelids. Length from 3.5 cm to 4 m. The body is covered with keratinized scales. Ya are distributed to... ... Encyclopedia "Animals in the House"
Suborder of reptiles of the order Squamate. The body is from a few centimeters to 3 m or more long (Komodo dragon), covered with keratinized scales. Most have well-developed limbs. More than 3900 species, on all continents (except Antarctica),... ... encyclopedic Dictionary
- (Lacertilia s. Sauria) reptiles with an anus in the form of a transverse slit (Plagiotremata), with a paired copulatory organ, with teeth not in meshes; usually equipped with a front girdle and always have a sternum; in most cases with 4... Encyclopedic Dictionary F.A. Brockhaus and I.A. Ephron
Lizards- Striped lizard. LIZARDS, animals of the reptile class. The body ranges from a few cm to 3 m or more in length (Komodo dragon), covered with keratinized scales. Most (agamas, iguanas, geckos, etc.) have well-developed limbs, some... ... Illustrated Encyclopedic Dictionary
Mn. Suborder of reptiles of the order Squamate. Ephraim's explanatory dictionary. T. F. Efremova. 2000... Modern explanatory dictionary of the Russian language by Efremova