The class Reptiles (reptiles) includes about 9,000 living species, which are divided into four orders: Scaly, Crocodiles, Turtles, Beakheads. The latter is represented by only one relic species - tuatara. The scaly ones include lizards (including chameleons) and snakes.
The quick lizard is often found in central RussiaGeneral characteristics of reptiles
Reptiles are considered the first true land animals, since they are not related in their development to aquatic environment. If they live in water (aquatic turtles, crocodiles), then they breathe with lungs and come to land for reproduction.
Reptiles are settled on land much more than amphibians, occupying more diverse ecological niches. However, due to being cold-blooded, they predominate in warm climates. However, they can live in dry places.
Reptiles evolved from stegocephalians (an extinct group of amphibians) at the end of the Carboniferous period of the Paleozoic era. Turtles appeared earlier, and snakes later than all.
The heyday of reptiles fell on the Mesozoic era. During this time, various dinosaurs lived on Earth. Among them were not only terrestrial and aquatic species, but also flying ones. Dinosaurs became extinct at the end of the Cretaceous.
Unlike amphibians, reptiles
improved head mobility due to a larger number of cervical vertebrae and a different principle of their connection with the skull;
the skin is covered with horny scales that protect the body from drying out;
breathing only lung; formed rib cage, which provides a more perfect breathing mechanism;
although the heart remains three-chambered, the venous and arterial circulations are better separated than in amphibians;
pelvic kidneys appear as organs of excretion (and not trunk ones, as in amphibians); such kidneys better retain water in the body;
the cerebellum is larger than that of amphibians; increased volume of the forebrain; the rudiment of the cerebral cortex appears;
internal fertilization; reptiles reproduce on land mainly by laying eggs (some are viviparous or ovoviviparous);
germinal membranes appear (amnion and allantois).
Reptile skin
The skin of reptiles consists of a multi-layered epidermis and a connective tissue dermis. The upper layers of the epidermis become keratinized, forming scales and scutes. The main purpose of the scales is to protect the body from water loss. In total, the skin is thicker than that of amphibians.
Reptile scales are not homologous to fish scales. Horny scales are formed by the epidermis, that is, it is of ectodermal origin. In fish, scales are formed by the dermis, i.e., are of mesodermal origin.
Unlike amphibians, there are no mucous glands in the skin of reptiles, so their skin is dry. There are only a few odorous glands.
In turtles, a bony shell forms on the surface of the body (above and below).
Claws appear on the fingers.
Since keratinized skin inhibits growth, molting is characteristic of reptiles. At the same time, the old covers move away from the body.
The skin of reptiles fuses tightly with the body, without forming lymphatic sacs, as in amphibians.
reptile skeleton
In comparison with amphibians, in reptiles, not four, but five sections are distinguished in the spine, since the trunk section is divided into the thoracic and lumbar.
In lizards, the cervical region consists of eight vertebrae (in different species there are from 7 to 10). The first cervical vertebra (atlas) looks like a ring. The odontoid process of the second cervical vertebra (epistrophy) enters it. As a result, the first vertebra can rotate relatively freely around the process of the second vertebra. This gives more head movement. In addition, the first cervical vertebra is connected to the skull with one mouse, and not two as in amphibians.
All vertebrae of the thoracic and lumbar have ribs. In lizards, the ribs of the first five vertebrae are attached by cartilage to the sternum. The chest is formed. The ribs of the posterior thoracic and lumbar vertebrae are not connected to the sternum. However, snakes do not have a sternum, and therefore do not form a chest. This structure is associated with the peculiarities of their movement.
The sacral spine in reptiles consists of two vertebrae (and not one as in amphibians). The iliac bones of the pelvic girdle are attached to them.
In turtles, the vertebrae of the body are fused with the dorsal shield of the shell.
The position of the limbs relative to the body is on the sides. In snakes and legless lizards, the limbs are reduced.
Digestive system of reptiles
The digestive system of reptiles is similar to that of amphibians.
In the oral cavity there is a movable muscular tongue, in many species forked at the end. Reptiles are able to throw it far.
Herbivorous species have a caecum. However, most are predators. For example, lizards eat insects.
The salivary glands contain enzymes.
Respiratory system of reptiles
Reptiles breathe only with the lungs, because due to keratinization, the skin cannot take part in breathing.
The lungs are being improved, their walls form numerous partitions. This structure increases the inner surface of the lungs. The trachea is long, at the end it divides into two bronchi. In reptiles, the bronchi in the lungs do not branch.
Snakes have only one lung (the right one, while the left one is reduced).
The mechanism of inhalation and exhalation in reptiles is fundamentally different from that of amphibians. Inhalation occurs when the chest expands due to stretching of the intercostal and abdominal muscles. At the same time, air is sucked into the lungs. When exhaling, the muscles contract and the air is pushed out of the lungs.
The circulatory system of reptiles
The heart of the vast majority of reptiles remains three-chambered (two atria, one ventricle), and arterial and venous blood is still partially mixed. But in comparison with amphibians, in reptiles, the venous and arterial blood flows are better separated, and, consequently, the blood mixes less. There is an incomplete septum in the ventricle of the heart.
Reptiles (like amphibians and fish) remain cold-blooded animals.
In crocodiles, the ventricle of the heart has a complete septum, and thus two ventricles are formed (its heart becomes four-chambered). However, blood can still mix through the aortic arches.
From the ventricle of the heart of reptiles, three vessels independently depart:
From the right (venous) part of the ventricle common trunk of the pulmonary arteries, which further divides into two pulmonary arteries, going to the lungs, where the blood is enriched with oxygen and returned through the pulmonary veins to the left atrium.
Two aortic arches depart from the left (arterial) part of the ventricle. One aortic arch begins to the left (however called right aortic arch, as it bends to the right) and carries almost pure arterial blood. From the right aortic arch originate the carotid arteries going to the head, as well as the vessels supplying blood to the girdle of the forelimbs. Thus, these parts of the body are supplied with almost pure arterial blood.
The second aortic arch departs not so much from the left side of the ventricle as from its middle, where the blood is mixed. This arch is located to the right of the right aortic arch, but is called left aortic arch, as it bends to the left at the exit. Both aortic arches (right and left) on the dorsal side are connected to a single dorsal aorta, the branches of which supply the organs of the body with mixed blood. The venous blood flowing from the organs of the body enters the right atrium.
excretory system of reptiles
Reptiles in progress embryonic development trunk kidneys are replaced by pelvic ones. The pelvic kidneys have long tubules of nephrons. Their cells are differentiated. In the tubules, water is reabsorbed (up to 95%).
The main excretory product of reptiles is uric acid. It is almost insoluble in water, so the urine is mushy.
The ureters depart from the kidneys, flowing into the bladder, which opens into the cloaca. In crocodiles and snakes, the bladder is underdeveloped.
Nervous system and sense organs of reptiles
The brain of reptiles is being improved. In the forebrain, the cerebral cortex appears from the gray medulla.
In a number of species, the diencephalon forms a parietal organ (third eye), which is able to perceive light.
The cerebellum in reptiles is better developed than in amphibians. This is due to the more diverse motor activity of reptiles.
Conditioned reflexes are developed with difficulty. The basis of behavior is instincts (complexes of unconditioned reflexes).
The eyes are equipped with eyelids. There is a third eyelid - the nictitating membrane. In snakes, the eyelids are transparent and grow together.
A number of snakes at the front end of the head have pits that perceive thermal radiation. They well determine the difference between the temperatures of surrounding objects.
The organ of hearing forms the inner and middle ear.
The sense of smell is well developed. In the oral cavity there is a special organ that distinguishes odors. Therefore, many reptiles stick out a forked tongue at the end, taking air samples.
Reproduction and development of reptiles
All reptiles are characterized by internal fertilization.
Most lay their eggs in the ground. There is a so-called ovoviviparity, when the eggs linger in the genital tract of the female, and when they leave them, the cubs immediately hatch. In sea snakes, a real live birth is observed, while in the embryos a placenta is formed, similar to the placenta of mammals.
Development is direct, a young animal appears, similar in structure to an adult (but with an underdeveloped reproductive system). This is due to the presence of a large supply of nutrients in the yolk of the egg.
In the egg of reptiles, two embryonic shells are formed, which are not found in the eggs of amphibians. This is amnion and allantois. The embryo is surrounded by an amnion filled with amniotic fluid. Allantois is formed as an outgrowth of the posterior end of the intestine of the embryo and performs the functions of the bladder and respiratory organ. The outer wall of the allantois is adjacent to the shell of the egg and contains capillaries through which gas exchange takes place.
Caring for offspring in reptiles is rare, it consists mainly in protecting the masonry.
Reptiles are what kind of animals? They belong to the class of vertebrates occupying a place between amphibians and mammals. We also call them reptiles. Reptiles is a list of names below:
- dinosaurs (fossil form);
- lizards;
- turtles;
- snakes;
- crocodiles.
Lifestyle
reptiles adjust to temperature environment being cold-blooded. In order not to freeze during the cold season, some may fall into seasonal hibernation. When temperatures are too high, they are more active at night. The skin of reptiles is tough, covered with scales. The main task of the scales is to protect from drying out. Turtles have a strong shell, while crocodiles have hard plates on their backs and heads. The bone skeleton is well developed in these animals. The ribs of snakes are designed so that they crawl with ease. The tongue of most reptiles is short. Only lizards and snakes have a long, forked, protruding mouth. The reproductive organs are similar to those of birds. In some, the eggs remain inside until hatching.
Reptiles Examples: Lizards
Lizards are the most large group from the list of reptiles. So sometimes they call all reptiles with legs, except for crocodiles, turtles. However, it is worth highlighting real lizards, related species.
Real lizards are small or slightly larger than average. In length, they reach a maximum of 80 cm, although mostly 20-40 cm. Their body, limbs, and color are adapted to their habitat. The desert representatives have long toes on their paws that have lateral teeth that do not allow them to fall into the sand. Interestingly, in case of danger, the lizard itself breaks its tail to distract the attacker. While the mistress is running away, the tail continues to writhe, distracting the predator. Males are larger than females, brighter colored. The color is dominated by green, gray, brown colors. Deserts are painted yellow. Most lizards do not make sounds. Only Stehlina and Simona, who live in the Canary Islands, squeak in case of danger.
area
They live mainly in Europe, Africa, Asia. AT North America they were brought. You can see a lizard in the forest, in the meadow, in the desert, steppe, or even in the garden. These reptiles instantly climb low bushes, crawl along tree trunks, grass stalks. Nimble, maneuverable, they move with ease on a vertical surface.
Lizards are active early in the morning or at sunset. Less mobile during the day. Very cautious, immediately freeze, only sensing danger. When a suspicious object approaches, they run away. Interestingly, desert species instinctively raise their paws in turn, so as not to get burned from hot sand.
Nutrition
This species of reptiles feeds on invertebrates. Larger representatives can catch a small rodent, a snake or eat bird masonry. They love to feast on spiders, butterflies, grasshoppers. Snails, worms are rare but found in their diet. Some species do not disdain the fruits of plants.
Protection from enemies
Hunt these beauties of the snake, big birds. Lizards use several methods to protect themselves: fast running, freezing, disguise. Interestingly, it is almost impossible to throw a lizard that has been hiding from a bush. If caught, then instantly discards the tail or bites hard. It can grab its own leg, twist into a ring - an excellent defense against a snake, because in this form the latter will not be able to swallow prey.
Reptiles examples: turtles
We continue our acquaintance with reptiles, the list of names continues turtles - the most known species reptiles. There are land and sea. Distributed throughout the world. You can keep them as a pet.
Description of turtles
The shell has a bone structure. The respiratory organ is the lungs. Aquatic animals absorb air through the mucous membrane of the pharynx. The main difference from other reptiles is longevity. The largest representatives of this species are marine. The length of the shell of the largest is 2 m, and it weighs more than 900 kg. The smallest turtle is only 10 cm long.
reproduction
To lay eggs, the female makes a pitcher-shaped hole. Then masonry future mom falls asleep, carefully rams. Depending on the variety, the number of eggs ranges from one to two hundred.
Character
These reptiles are solitary in nature. Communicate with their own kind only during the mating season. Land animals mainly use plants as food, but freshwater ones are predators. It happens that babies can lead a predatory lifestyle, and as adults, switch to plant foods.
Reptiles examples: snakes
The main difference from other reptiles is the shape of the body
In the torso of these reptiles we will find three elements: the head, the body itself, and the tail. They do not have limbs, eyelids, external auditory canal.
Differences from reptiles
Most snakes are venomous. The poison is in the teeth. very different internal organs these reptiles. For example, there is no bladder. There is a cornea on the eyes. Nocturnal representatives have a transverse pupil, while nocturnal representatives have a vertical pupil. They can only hear loud sounds.
Separately, it is worth highlighting already
These snakes are not poisonous. The scales are painted in a bright color. They live near water bodies. They feed on fish, can catch small mammals. They swallow their prey whole. If he already sensed danger, he freezes, when the enemy approaches, he emits a smelly liquid from his mouth. Reptiles breed on plant soil.
Reptiles Examples: Crocodiles
The most dangerous kind reptiles. The size of the ancient representatives exceeded 15 meters in length. Remains have been found on all continents. Modern crocodile is much smaller, but they are still the largest reptiles.
Way of life
Most of the time they are in the water. On the surface, only the organs of vision, hearing, nose. The tail and paws are webbed, which allows them to swim well. However, crocodiles do not swim to great depths. These reptiles build their nests on land. They only come out of the water to warm up. They have a powerful tail, move quickly in water and on land. They attack unexpectedly. Therefore, they are extremely dangerous for humans.
Reptiles, list: to summarize
In total, more than six thousand reptiles are known to man, which are distributed throughout the globe. They mainly live on land. They are best suited for a warm climate with moderate humidity. However, among the reptiles there are desert dwellers. Most representatives of snakes, crocodiles are very dangerous for human life. However, there are benefits from these reptiles. For example, scientists have learned to use snake venom for medicinal purposes. It increases blood clotting, preparations based on it reduce pain in rheumatism, neuralgia. More than two thousand snakes are not poisonous at all, but they feed on harmful rodents, reducing their number in their habitat. Expensive haberdashery products are made from crocodile skin. Reptile meat is also used as food and is considered a delicacy. Eggs and turtle meat are valued in this sense.
Reptiles, like any other, can pose some danger to humans, only if they behave incorrectly. AT modern world you can admire an alligator or a rattlesnake without fear for your own life. Meeting in real life we are practically not threatened with them.
Turtles, crocodiles, lizards, snakes... Did you know that they are all reptiles, like the long-extinct dinosaurs? Their skin is covered with scales, plates or shells. And unlike mammals or birds, their body temperature changes depending on the temperature of the environment.
Almost all reptiles are carnivores. Their jaws - with many teeth, which are needed to grab prey, and not chew or tear: they swallow it whole. In most species, the females lay eggs, which later hatch into young. But there are also ovoviviparous: cubs hatched in the mother's body are born without a shell, like a viper.
In the modern era, there are about 6,000 species of reptiles, living mainly in hot countries (crocodiles, many snakes). Those who have adapted to a colder climate (lizards and especially snakes) are forced to spend the winter in a state of stupor, in hibernation. With the exception of some aquatic species ( sea turtles and snakes of the Indian and Pacific Oceans), reptiles, as a rule, are homebodies and do not move far from their territory. And very rarely show craving for life in the pack.
Amphibians
Amphibians, or, in other words, amphibians, as their name indicates, divide their lives between two environments: water and land. They breed in the water, where the females lay their eggs, from which the tadpoles hatch. These herbivorous babies with a large head, followed immediately by a long tail, breathe through gills and lead an aquatic, “fishy” lifestyle.
Double life
Developing, the tadpole passes through several successive stages. First, his legs grow (back, then front), then the tail falls off and finally the gills are replaced by lungs. The animal becomes an adult and begins to breathe air, but continues to spend part of its life in water: it reproduces there.
Amphibians are divided into three groups: The first, the most primitive, are legless amphibians. similar to earthworms. Then come the tailless ones; their adults do not have a tail: frogs, tree frogs, toads. And finally, tailed ones, which do not lose their tail with age. These include black and yellow salamanders and newts, which differ from the former in brighter colors. Like reptiles, amphibians have variable body temperatures. They are distributed mainly in hot and temperate regions.
Balkan turtle- dl. (shell) from 10 to 20 cm
Chameleon- dl. from 10 to 80 cm
elephant turtle- dl. (shell) 1.2 m
green lizard- dl. from 20 to 35 cm
Sea turtle- length (shell) from 1.3 to 1.9 m
Copperhead- dl. from 30 to 45 cm
Caiman- dl. from 1.5 to 4.5 m
monitor lizard- dl. from 20 cm to 4 m
Alligator- dl. from 4 to 6 m
Nile crocodile- dl. from 5 to 9 m
giant salamander- dl. 1.5 m
Python- dl. from 4 to 10 m
Already ordinary- dl. from 50 to 70 cm
crested newt- dl. 15 cm
Viper- dl. 55 cm
green frog- dl. from 5 to 12 cm
Axolotl- dl. 20 cm
tree frog- dl. 5 cm
common toad- dl. from 7 to 15 cm
Amphibians and reptiles
Amphibians (amphibians), like reptiles (reptiles), are ancient terrestrial vertebrates. They are ubiquitous, but prefer areas with a warm and hot climate. Amphibians live near bodies of water and in damp places; their development takes place in water. Reptiles are not connected in their development with the aquatic environment.
Main characteristic
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Sections |
Amphibians |
reptiles |
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It is divided into head, torso and five-fingered limbs. Tailed amphibians have a tail. |
It is subdivided into the head, neck, torso, tail and five-fingered limbs. |
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Thin, devoid of scales, but has a large number of glands that secrete mucus. |
Dry, devoid of glands and covered with horny scales that protect the body from drying out. Scales hinder growth, so molting is typical for reptiles. |
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Spine |
4 departments: cervical, trunk, sacral and tail. The ribs are reduced; they are absent in anurans. Musculature does not have a segmental structure and is represented by differentiated muscle groups. |
5 sections: cervical, thoracic, lumbar, sacral and caudal. There are ribs, sternum and chest. The parts of the skeleton of the limbs are the same as in amphibians. The muscles are more differentiated. |
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Digestive system |
The alimentary canal is subdivided into anterior, middle, and posterior sections. Isolated stomach. The expansion of the large intestine forms a cloaca. Developed digestive glands. |
Oral cavity, pharynx, esophagus, stomach, small and large intestines. On the border of the large and small intestines is the rudiment of the caecum. The large intestine opens into the cloaca. Developed digestive glands. |
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excretory organs |
Paired trunk ureters and bladder, which opens into the cloaca. |
Secondary (pelvic) kidneys, ureters, bladder (opens into the cloaca). |
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Circulatory system |
The heart is three-chambered. Two circles of blood circulation. Mixed blood flows through the vessels of the large circle, and the brain is supplied with arterial blood. Amphibians are poikilothermic animals. |
The heart is three-chambered, but there is an incomplete septum in the ventricle. Two circles of blood circulation. |
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Respiratory system |
Adult animals have lungs, larvae have gills. In addition, the skin is involved in respiration. |
Lungs. They are stretchable bags, the inner mesh of which has a network of crossbars that increase the surface. The posterior end of the trachea branches into two bronchi, which enter the lungs. |
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Nervous system |
The brain consists of 5 sections. The forebrain is larger than that of fish and is divided into two hemispheres. The cerebellum is less developed. Developed organs of vision, hearing, taste, smell, touch. |
The progressive development of the brain is associated with the appearance of the rudiments of the cerebral cortex. The cerebellum is well developed. The sense organs are adapted to the terrestrial way of life. The eyes have eyelids. The lens is able to change curvature. The organ of hearing consists of the inner ear (compared to amphibians, the larger size of the cochlea) and the middle ear (one auditory ossicle and eardrum). Developed organs of smell, touch, taste. |
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reproduction |
Amphibians are dioecious animals. Fertilization takes place in water; development with incomplete metamorphosis. |
Reptiles, like amphibians, have separate sexes. Fertilization is internal. Development is often direct (oviposition), there is also a live birth. |
The value of amphibians and reptiles
Amphibians destroy a large number of insect pests of agricultural crops. They are food for fish, birds, snakes and some fur-bearing animals. In a number of countries, frogs are also used as food by humans. The frog is a classic subject for scientific research.
Reptiles are one of the links in food chains in the biosphere. Man uses the meat and eggs of turtles as food, as well as the meat of snakes. The skin of snakes and crocodiles is a valuable raw material for industry. Snake venom is used to obtain medicines. The poison is collected from snakes kept in special nurseries - serpentaria. Snakes destroy a significant number of rodents - pests of agricultural crops.
Amphibians and reptiles of the Yaroslavl region
Amphibians. The species composition of amphibians living in the Yaroslavl region is relatively poor and is represented by 10 species. Tailed amphibians are represented by common and crested newts. Tailless include two types of brown and two types of green frogs (grass, moor, lake and pond frogs), red-bellied toad, spadefoot, gray and green toads. Red-bellied toad, spadefoot and green toad are listed in the Red Book of the Yaroslavl region.
Tritons are tailed amphibians, somewhat reminiscent of lizards in appearance. Common and crested newts are found in our reservoirs. The most common is the common newt, reaching 8-9 centimeters in length. For breeding, newts choose well-warmed reservoirs located in clearings, forest edges and clearings. So far, common newts are not uncommon in the reservoirs of urban gardens and parks.
The crested newt is much larger than the common newt, its length is more than 15 cm. The body is massive, the head is flattened and wide. In males, the crest is high, serrated, sharply separated by a notch from the tail. The crested newt is quite rare, avoids polluted water bodies and encounters with humans, and therefore does not occur in urban water bodies. This newt lives mainly in the forest zone, preferring deeper water bodies for breeding than the common newt.
Both types of newts are extremely useful animals. Living in a reservoir, adult newts and their larvae destroy a huge number of mosquito larvae. Many harmful insects are eaten by newts and living on land. And, finally, they themselves are included in the menu of many animals and birds - snakes, vipers, herons, storks, small predatory mammals. Drainage of shallow water bodies, the destruction of both adult newts and their eggs leads to a decrease in the number of newts.
More often than newts in water bodies and on land there are frogs. Brown frogs differ from other frogs similar to them by a dark temporal spot. These include herbal and moor. And, despite their almost identical size (about 8 cm) and similar coloration (their backs are brown, of different shades), these frogs are easily distinguishable. The common frog has a marble spotted pattern on the underbelly of the abdomen (in males it is off-white, and in females it is reddish-brown). If you come across a frog with a plain belly and a little smaller size, then this is a moored one. The lake frog is the largest of those living in our country. The length of her body can sometimes reach 17 cm. The lake frog constantly lives in the water. Pond frogs differ from lake frogs in their smaller size and emerald or bright olive color.
Common spadefoot lives on the plains in the forest zone, preferring areas with loose soil. In the Yaroslavl region, rare sightings were noted in the Lyubimsky district. Listed in the Red Book of nuclear weapons.
The body length of the spadefoot is up to 71 mm. The main tone of the color is gray or brown, on the back there is a more or less symmetrical pattern of dark spots, sometimes forming stripes; the edges of the spots are clearly defined. A light stripe runs along the back. The underside of the body is light with dark gray spots. A characteristic feature of this frog is the ability to quickly burrow into the soil, using the hind limbs and a large calcaneal tubercle for this. Garlic is a dry-loving species. In water bodies, it is found only during the breeding season.
Red-bellied toad inhabits lowland areas in floodplains of rivers and lakes, ponds and swamps. In the Yaroslavl region, rare encounters were noted in the Breitovsky and Poshekhonsky districts. Listed in the Red Book.
The body length of this frog is not more than 64 mm. The back is brown-gray with dark, rarely green spots. The belly of the toad is bright with large dark and orange or red spots. In case of danger, the toad takes a characteristic pose - it turns upside down, showing a bright warning color. Outside the breeding season, toads prefer shallow sun-warmed pools or shallow waters overgrown with aquatic vegetation, where they spend a lot of time. In the forest, the toad can be found on the edges, glades and clearings.
Of the toads in the Yaroslavl region, there are gray, or common and green toads. Unlike their closest relatives - frogs, toads are not demanding on water. Their skin is partially keratinized, so they can live in the forest quite far from water bodies. They are of great benefit, destroying slugs, mosquito larvae and harmful insects.
The common toad prefers forest landscapes, but gets along well with humans and is common in parks, gardens, fields, vegetable gardens and household plots. These animals prefer damp places with tall grass. Adult toads are active mainly at dusk and the first half of the night. In hot weather, they hide in shelters under stones, snags, haystacks. Young toads are active around the clock, and in damp places with thick grass they come across even in hot weather.
Green toads differ from gray ones in more varied colors: large dark green spots with a black border and red dots are scattered on the back on an olive background. Sometimes a light stripe runs along the back. Belly whitish, with or without spots. In addition, green toads are more dry-loving and thermophilic than gray ones. These animals are able to tolerate large losses of water and are adapted to life in very dry conditions. In the Yaroslavl region, rare encounters were noted in the Pereslavl and Rostov regions.
The number of toads is affected by human disturbance and direct extermination, as well as the disturbance of natural habitats as a result of human economic activities.
Reptiles. The natural conditions of the Yaroslavl region are not very favorable for the existence of reptiles, therefore they are represented by six species - three species of lizards and three species of snakes.
Common snake and common viper can be called ordinary and common snakes of the Yaroslavl region. Already distinguished by yellow (or almost white or orange) spots on the sides of the head. The general color tone of the viper, a venomous snake, varies from light gray to black. An almost black zigzag stripe stretches along the back; between the head and the body there is a sharp interception, and on the head we can clearly distinguish the pattern in the form of the Latin letter "x". Common vipers are most often found in marshy forests along the outskirts of swamps, in forest clearings and edges with good herbage, in clearings, along the banks of rivers and lakes. On hot sunny days, vipers crawl out to bask in the sun. At this time, they can often be seen on an old stump or even on a well-trodden forest path. Often found in household plots, recreational areas.
According to studies conducted in 2010, more than 500 thousand common vipers constantly live in the Yaroslavl region. The population of vipers is quite stable, tends to increase in numbers and so far does not need additional protection measures.
Destroying mouse-like rodents, snakes and vipers bring considerable benefits.
In the Yaroslavl region, sporadic sightings of the copperhead snake, which has an international rank of protection, were noted in the Pereslavl region. Copperhead belongs to the family of snakes. When meeting with a person, this snake usually curls up into a tight ball, inside which it hides its head, and reacts to all touches with an even greater contraction of the body. Copperhead is listed in the Red Book of the Yaroslavl region.
Of the lizards, two types of true lizards are most common - nimble and viviparous. They are small in size - the first is no more than 25 centimeters (together with the tail), the second is slightly shorter - 20 centimeters. A quick lizard can be found even in a city park. It adapts well to human-modified landscapes, preferring dry and sunny areas, hillsides and even railway embankments. The viviparous lizard lives in more humid places, in forested areas of swamps, peat bogs, overgrown clearings, along river banks.
Both types of lizards are useful, exterminate slugs, bears, caterpillars, harmful insects and their larvae.
In the Yaroslavl region, there is also a legless lizard - brittle spindle, or sucker. Unfortunately, this animal is often confused with the copper snake and other snakes (including poisonous ones), they are frightened and even destroyed. The serpentine body of the spindle reaches a length of 60 cm (including the tail). Young animals are usually very light. Adults are brown or bronze above with darker sides. Underside is bluish black. Males have blue or blue spots on their backs. The body of the lizard is covered with small, very smooth and shiny scales.
In our area, the spindle is much rarer than other species of lizards. It lives mainly in mixed and broad-leaved forests, also occurring at the forest border along the outskirts of fields and meadows, in forest clearings and clearings, in gardens. Useful.
Amphibians (amphibians). This is a small group of the most primitive terrestrial vertebrates (Fig. 87). Depending on the stage of development, most of them spend part of their lives in water. The ancestors of amphibians were lobe-finned fish that lived in fresh, drying water bodies.
Rice. 87. Amphibians: 1 - newt; 2 - spotted salamander; 3 - proteus; 4 - axolotl (ambistoma larva); 5 - pond frog; 6 - pipa; 7 - worm
In the larval stage (tadpoles), amphibians are very similar to fish: they retain gill breathing, have fins, a two-chambered heart, and one circle of blood circulation. Adult forms are characterized by a three-chambered heart, two circles of blood circulation, two pairs of limbs. The lungs appear, but they are poorly developed, so additional gas exchange occurs through the skin (see Fig. 85). Amphibians live in warm, humid places, especially common in the tropics, where they have suitable climatic conditions.
These are separate animals. They are characterized by external fertilization and development in water. From the eggs of a tailless amphibian, such as a frog, a tailed larva emerges - a tadpole with long fins and branched gills. As it develops, the forelimbs appear, then the hind limbs, and the tail begins to shorten. Branched gills disappear, gill slits (internal gills) appear. From the anterior part of the digestive tube, lungs are formed, as they develop, the gills disappear. There are corresponding changes in the circulatory, digestive and excretory systems. The tail resolves, and the young frog comes to land. In caudate amphibians, the gills remain much longer (sometimes for a lifetime), the tail does not resolve.
Amphibians feed on animal food (worms, molluscs, insects), but the larvae living in the water can be herbivorous.
There are three groups of amphibians: caudate(newt, salamander, ambistoma), tailless(toads, frogs) legless, or worms(fish snake, worm).
Tailed amphibians the most primitive. They live in and near water, and their limbs are usually poorly developed. Some have feathery gills throughout their lives.
Ambystoma larva - axolotl even starts breeding before reaching the adult stage. Salamanders are the most numerous.
Worms- a very small family. They have no limbs, the body is elongated, reminiscent of a worm or a snake.
The most prosperous group tailless amphibians. They have a short body and well developed limbs. During the breeding season, they "sing" - make various sounds (croak).
Reptiles (reptiles). Reptiles are terrestrial vertebrates. They adapted well to life on land and displaced many of their amphibian ancestors. Reptiles have a three-chambered heart. They begin to separate arterial and venous blood due to the appearance incomplete septum in the ventricle of the heart; better than amphibians, developed nervous system: the hemispheres of the brain are much larger (see Fig. 85). The behavior of reptiles is much more complex than that of amphibians. In addition to congenital unconditioned, they also form conditioned reflexes. Digestive, excretory and circulatory systems open into cloaca- Part of the intestine.
The body of reptiles is covered with scales. It is formed in the thickness of the skin - the epidermis - and protects the body from drying out. Some species shed their scales during molting (snakes, lizards). The lungs of reptiles are much larger and more voluminous than those of amphibians, due to the cellularity.
Reptiles are dioecious animals. Fertilization is internal. The female lays eggs in the sand or in the soil in small depressions, covered with a leathery shell. Even among aquatic inhabitants, the development of eggs takes place on land. Some species are characterized by live birth.
Reptiles reached their greatest prosperity in the Mesozoic era, about 100-200 million years ago, therefore this era is called the era of reptiles. There were a huge number and variety of them: dinosaurs - on land, ichthyosaurs - in water, pterosaurs - in the air. Among them were species of enormous size, as well as rather small forms, the size of a cat. Almost all of them died out about 70 million years ago. The cause of extinction is still not fully understood. There are several hypotheses: sudden abrupt change climate, the fall of a giant meteorite, etc. But all of them do not fully explain this riddle.
Currently, there are four main groups: turtles, snakes, lizards and crocodiles (Fig. 88).
Rice. 88. Reptiles: 1 - steppe gecko; 2 - agama; 3 - eared round head; 4 - frilled lizard; 5 - gray monitor lizard; 6 - spectacled snake; 7 - rattlesnake; 8 - already
characteristic feature turtles is the presence of a shell, consisting of bone plates and covered with a horny substance. Representatives of this group can live both on land and in water. Giant and elephant tortoises (up to 110 cm long) are the largest of those living on land. They are common in the Galopogos Islands. Pacific Ocean, Madagascar, Indian Ocean Islands.
Sea turtles are much larger (up to 5 m), have flipper-like legs. They live in water all their lives, but they lay their eggs on land.
lizards very varied. This is the most prosperous group. These include chameleons, geckos, iguanas, agamas, roundheads, monitor lizards and true lizards. Most lizards are characterized by an elongated body, a long tail, and well-developed limbs. Some (yellow bellies) have lost limbs, they resemble snakes.
At snake the main feature is a long, limbless body. They are crawling animals. All snakes are predators; they swallow prey whole or strangle it, squeezing it in the rings of their bodies. The poisonous glands (modified salivary glands) open with a duct at the base of the poisonous tooth. Snakes include: viper, gyurza, cobra, python, boa constrictor, as well as snakes - non-poisonous representatives of this group.
crocodiles Of all reptiles, they are closest to mammals. Their heart can be called four-chambered, there is a bony palate, air enters through the nostrils into back mouth. In terms of the structure of the oral cavity and the location of the tongue, they are closer to mammals than to other reptiles. These are rather large tailed animals that live in the water, along the banks of rivers. On land, they move slowly, but they are excellent swimmers. Females lay calcareous-shelled eggs on land in small pits. They are characterized by caring for offspring: the female guards the clutch and takes care of the cubs.
Reptiles live mainly in warm climates: tropics, subtropics, wet and dry places: deserts, swamps, forests. Their food is also varied: plants, insects, worms, mollusks, and large individuals eat birds and mammals. All reptiles swallow their food whole. Many species feeding on pests Agriculture(insects, rodents) are of great benefit to humans. Snake venom is used to make many medicines. Shoes and handbags are made from the skin of snakes and crocodiles, which previously led to the mass extermination of animals. Currently, many species are under protection, they are grown on farms and in nurseries.
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§ 62. Chordates. Fish§ 64. Birds
