Snakes (Latin Serpentes)- suborder of reptiles of the squadron scaly.

Live snakes are found on all continents except Antarctica and several large islands such as Ireland and New Zealand, as well as many small islands in the Atlantic Ocean and the central Pacific Ocean.

Snakes have mastered almost all the living spaces of the Earth, except for the air. Snakes are found on all continents except Antarctica.

They are distributed from the Arctic Circle in the north to the southern tip of the American mainland. Snakes are especially numerous in tropical regions of Asia, Africa, South America and Australia.

They live in various ecological conditions - forests, steppes, deserts, foothills and mountains. They prefer areas with hot climates.

Snakes are mostly terrestrial, but some species live underground, in water, in trees. When unfavorable conditions occur, for example, as a result of a cold snap, snakes hibernate.

Among the variety of snakes, there are both harmless and poisonous representatives that are very dangerous for humans and animals. Most snakes do not have poison, and poisonous ones use poison primarily for hunting, and not for self-defense. Some species have a powerful poison, the action of which is enough to cause painful injury or even death. Non-venomous snakes either swallow their prey whole (snakes), or pre-kill (strangle) it (snakes, boas).

The largest snakes living on Earth are the reticulated boa constrictor and the anaconda water boa. The smallest snakes living on the planet - Leptotyphlops carlae - reach a length of no more than 10 centimeters. Most snakes are small reptiles, about 1 meter long.

The study of snakes is the science of serpentology.

The body of the snake is elongated, without extremities. Body length from 10 cm to 12 m.

Snakes differ from legless lizards by the movable connection of the left and right parts of the jaws (which makes it possible to swallow the prey whole), the absence of movable eyelids and the tympanic membrane, and the absence of the shoulder girdle.

The snake's body is covered with scaly skin. Snake skin is dry and smooth. In most snake species, the skin on the side of the abdomen is adapted for more grip, making it easier to move around. The eyelids of the snake are represented by transparent scales and remain permanently closed. Changing the skin of a snake is called flaking or shedding. In snakes, the skin changes at once and in one layer. Despite the apparent heterogeneity, the skin of the snake is not discrete and sloughing of the upper layer of the skin (epidermis), in the process of molting, resembles turning the stocking inside out.

Molting occurs periodically throughout the snake's life. Before molting, the snake stops eating and often hides, moving to safety. Shortly before shedding, the skin becomes dull and dry in appearance, and the eyes become cloudy or blue in color. The inner surface of old leather is liquefied. This causes the old skin to separate from the new skin underneath. After a few days, the eyes clear up and the snake "crawls" out of its old skin. At the same time, the old skin bursts in the area of ​​the mouth and the snake begins to wriggle, using the force of friction, resting on the rough surface. In most cases, the process of shedding old skin is carried out backward along the body, that is, from head to tail in a single piece, as when trying to turn a sock inside out. Thus, a new, larger and brighter layer of skin is formed under the old one.

Adult snakes are only able to change their skin once or twice a year. Younger (younger) snakes that continue to grow can molt up to four times a year. The shed skin is an ideal imprint of the outer cover, which can usually be used to identify the species of the snake, provided the shed skin remains intact.

In their search for prey, snakes track odors using a forked tongue to collect particles from the environment and then transfer them into the mouth for examination (vomeronasal organ or Jacobson's organ). The tongues of snakes are constantly in motion, taking samples of air, soil, water particles and analyzing the chemical composition, they can detect the presence of prey or predators and determine their position on the ground. In water-dwelling snakes, the tongue functions effectively under water (for example, in the anaconda). Thus, the tongue in the form of a fork in representatives of this genus makes it possible to directionally smell and determine taste at the same time.

All known snakes are predators. They feed on a variety of animals: vertebrates and invertebrates. There are types of snakes that specialize in eating a certain type of prey, that is, stenophages. For example, a crustacean snake (Regina rigida) feeds almost exclusively on crayfish, and egg snakes (Dasypeltis) - only on bird eggs.

Non-venomous snakes swallow their prey alive (for example, snakes) or preliminarily kill it by squeezing with their jaws and pressing the body to the ground (slender snakes) or suffocating in body rings (boas and pythons). Poisonous snakes kill prey by injecting poison into its body with the help of special venom-conducting teeth.

Snakes tend to swallow their prey whole. The mechanism of swallowing consists in alternating movement of the right and left halves of the lower jaw.

The snake's eyes are covered with special transparent scales (Brille) - motionless eyelids. Thus, their eyes always remain open, even during sleep, the retinas can be covered or hidden by the rings of the body.

The vision of various representatives of the Snake genus varies widely: from the ability to only distinguish light from darkness to sharp vision, but the main difference is that their perception, although not sharp, allows them to adequately track movement. As a rule, vision is best developed in representatives of tree snakes and weakly in burrowing snakes, which lead mainly an underground lifestyle. Some snakes (for example, representatives of the genus Ahaetulla) have binocular vision (both eyes are able to focus on the same point).

Compared to other reptiles, snakes have the most developed thermal sensory organ, which is located in the facial fossa between the eye and nose on each side of the head. Vipers, pythons, and boas have sensitive receptors located in deep grooves on the snout, which allow them to "see" the heat emitted by warm-blooded prey, for example mammals. Others are equipped with heat receptors lining the upper lip, just below the nostrils. In pit-headed snakes, thermal radars can even determine the direction of the source of thermal radiation. At the same time, they perceive infrared radiation emanating from surrounding objects, not as electromagnetic waves, but precisely as heat.

Snakes do not have external ears, but snakes feel vibration from the ground and sounds in a rather narrow frequency range. Parts of the body that are in direct contact with the environment are very sensitive to vibration. Thus, snakes sense the approach of other animals, detecting faint vibrations in the air and on the ground.

Most snakes reproduce by laying eggs. But some species are ovoviviparous or viviparous.

Currently, there are more than 3000 species of snakes on Earth, united in 23 families and 6 superfamilies. Poisonous snakes account for about a quarter of the known species. This suborder of snakes also includes the extinct family Madtsoiidae. Sanajeh indicus, described in 2010, has been assigned to this family. Lived about 67 million years ago. The snake was 3.5 meters long. The bones were found in 1987. Along with the bones of Sanajeh indicus, fossilized shell remains were also found. This is the first evidence that snakes ate eggs and baby dinosaurs.

Scientific classification

Kingdom: Animals
Subkingdom: Eumetazoi
Type: Chordates
Subtype: Vertebrates
Infratype: Jawstomes
Superclass: Quadruped
Class: Reptiles
Subclass: Diapsids
Infraclass: Lepidosauromorphs
Superorder: Lepidosaurus
Order: Scaly
Suborder: Snakes

  • Family Aniliidae - Rolled snakes
  • Family Bolyeriidae - Bolierids
  • Family Tropidophiidae - Ground boas
  • Superfamily Acrochordoidea
  • Family Acrochordidae - Warty snakes
  • Superfamily Uropeltoidea
  • Family Anomochilidae
  • Family Cylindrophiidae - Cylindrical snakes
  • Family Uropeltidae - Shield-tailed snakes
  • Superfamily Pythonoidea
  • Family Loxocemidae - Mexican ground pythons
  • Family Pythonidae
  • Family Xenopeltidae - Radiant snakes
  • Superfamily Booidea
  • Family Boidae - False-legged snakes
  • Superfamily Colubroidea
  • Family Colubridae - Shaped
  • Family Lamprophiidae
  • Family Elapidae - Aspidaceae
  • Family Homalopsidae
  • Family Pareatidae
  • Family Viperidae - Vipers
  • Xenodermatidae family
  • Superfamily Typhlopoidea (Scolecophidia)
  • Family Anomalepididae - American worm-like snakes
  • Family Gerrhopilidae
  • Family Typhlopidae - Blind snakes
  • Family Leptotyphlopidae - Narrow snakes
  • Family Xenotyphlopidae

Snakes
(Serpentes),
suborder of reptiles of the squamous order (Squamata). Legless animals with a thin, highly elongated body, devoid of mobile eyelids. Snakes are descended from lizards, so they have many similarities with them, but two obvious signs almost always make it possible to accurately distinguish between the two groups. The vast majority of lizards have limbs. Snakes do not have front legs, although rudiments of the hind legs are sometimes noticeable in the form of claws. Legless lizards, outwardly very similar to snakes, have movable eyelids. Snakes also differ in the features of the structure of the head and body, associated with their peculiar way of feeding. It is known approx. 2,400 modern snake species. Although most of them live in the tropics and subtropics, the suborder is distributed almost throughout the world. Snakes are absent only in areas with permafrost, since during hibernation they need an underground shelter to survive the cold season. Only a few species live in the seas. About 500 species of snakes are venomous; of these, about half represent a serious danger to humans.
Anatomy and physiology. Snakes, like all other reptiles, are vertebrates. Their spine can have hundreds of vertebrae. The large number of the latter and, as a result, the tremendous flexibility of the body distinguish snakes among all reptiles. The vertebrae of snakes are complex and firmly connected to each other. There are almost as many pairs of ribs as there are non-caudal vertebrae. The absence of limbs does not limit the mobility of snakes, since a long body allows them to develop special, very effective ways of locomotion and catching prey. Specific ways of swallowing it also compensate for leglessness, and these reptiles, using their jaws and coiled bodies, surprisingly deftly "manipulate" even relatively large objects. Snake scales are thickening of the outer layer of the skin. Its living tissues grow, and the cells on the surface become strongly keratinized, become rigid and die off. There are areas of thin elastic skin between the scales, which allows the integument to stretch, and snakes to swallow objects of even larger diameter than themselves. As it grows, the snake sheds. To shed the outer layer of skin, she first tears it apart around the mouth opening by rubbing her head against the ground or other hard surface. Then the snake pulls off the old covers, sliding them back and turning them inside out. Often the skin comes off in one piece, like a stocking. The snake sheds for the first time at the age of several days, and young animals renew their covers much more often than adults. On average, molt occurs more often than once a year, but its frequency depends on the species and characteristics of the habitat. The discarded skin (crawling) is colorless, and the pattern on it is very weakly visible. The pigment cells that stain the integument of the snake lie deeper - in living tissue. Although the patterns are very diverse, three main types can be distinguished: longitudinal stripes; transverse stripes on the back or completely encircling the body at regular intervals; evenly distributed spots. The drawing is often camouflage in nature and allows the snake to blend in with the background. Determining the sex of an animal by color, as well as by other external signs, is difficult even for a specialist. However, the females of most species are larger than the males, and their tail is shorter. The length of the smallest snakes is only 12.5-15 cm with a mass of no more than 10-15 g. But the giants exceed 9 m in length and weigh hundreds of kilograms, being actually the longest among modern terrestrial vertebrates, and the fossil species were twice as long as the current ones. There are different opinions about the size limits for snakes. Some herpetologists consider the maximum length of 11.4 m, attributing it to the anaconda (Eunectes murinus), a giant boa constrictor from South America. The largest snake in North America is an ordinary boa constrictor (Boa constrictor) up to 5.6 m long, which, however, is rare for him. Seven species longer than 5.4 m are either boas or pythons, with the exception of the poisonous king cobra (Naja hannah) up to 5.5 m long, which is found in South and Southeast Asia. Snakes, along with fish, amphibians and other reptiles, are cold-blooded, or ectothermic, animals. This means that they, unlike mammals and birds, do not generate enough heat to maintain a constant body temperature. Therefore, snakes love to bask in the sun. However, they are poorly protected from overheating, which quickly kills them. At least one species of pythons cannot be called completely cold-blooded, since the female is able to slightly warm the laid eggs by curling around them in a ring.
Nutrition. Medium to large snakes feed almost exclusively on other reptiles, mammals, birds, amphibians and fish. Many small species eat insects and other invertebrates. Prey is almost always captured alive and, if it is harmless or difficult to kill, the same is swallowed. Snakes immobilize large, vicious or too mobile animals with poison, strangle or simply crush, entwining them with their bodies. Seizing large prey, the snake firmly holds it with its mouth with the help of numerous sharp, backward-bent teeth. During swallowing, it widely spreads the branches of the lower jaw and pulls them away from the cranium. This is possible due to the fact that the corresponding bones are connected by elastic ligaments, and the upper jaw is also mobile. Each half of the lower jaw, independently of the other, moves forward along the victim, pushing it down the throat. Then the pharynx muscles and body movements are included in the process, helping the snake, as it were, to be strung on a lump of food. No crushing or chewing takes place. The process of swallowing a large victim can take more than an hour. While the jaws and pharynx squeeze it, the trachea, reinforced with cartilaginous rings, moves downward so the snake can breathe. In this way, the animal can swallow prey larger than it, if only it is of a comfortable shape. The ability to eat large animals allows some snakes to feed only a few times a year. However, the same species can also swallow small prey, which, of course, have to be harvested much more often. Three or four hearty "meals" a year, especially in case of prolonged hibernation, is quite enough to maintain good shape, and there are many cases when snakes did not eat at all for a year or even longer.
Locomotion. It is generally believed that snakes crawl very quickly, but careful observation proves the opposite. A good speed for a large snake is about the same as a pedestrian, and most species move more slowly. The maximum speed for these reptiles, and then at a short distance, is slightly more than 10 km / h. Usually snakes crawl, bending in an S-shaped horizontal plane when their body is pressed to the ground. The translational movement is due to the fact that the back side of each bend is repelled by the unevenness of the substrate. A snake, crawling on loose sand, leaves behind itself at equal distances elongated hillocks, which have risen under the pressure of its body on the ground. This common mode of locomotion is known as lateral undulating, or simply "serpentine". The animal cannot move in this way on a smooth surface. However, it is used for swimming, and snakes swim well. Their eyes, protected by a transparent film and the ability to hold their breath for a long time, greatly facilitate movement in the water. The so-called "caterpillar track" is sometimes used by large, heavy snakes. At the same time, they move in a straight line due to wave-like contractions that underlie the skin of the muscles. Waves run one after the other from the neck back, and the shields on the animal's belly are repelled by the unevenness of the ground. "Sideways" is used by snakes on loose sands. Either the front or the back of the body is in turn thrown closer to the target, meeting the minimum resistance on the way. The snake seems to be walking, or rather, "jumping", keeping sideways to the direction of movement. Most snakes climb well. In specialized arboreal forms, the long transverse abdominal plates are curved outward at the sides, forming two longitudinal ridges, one on each side of the belly.
Reproduction. With the onset of breeding season, snakes are actively looking for a sexual partner. At the same time, excited males use a chemical analyzer, "sniffing" the air with their tongue and transferring them tiny amounts of chemicals left in the environment by the female to the paired Jacobson organ in the sky. Courtship helps to recognize partners: each species uses its own special stereotypes of movements. In some species, they are so complex that they resemble a dance, although in many cases the males simply rub their chins against the back of the female. Eventually the partners are intertwined with their tails and the male's hemipenis is inserted into the female's cloaca. The copulatory organ in snakes is paired and consists of two so-called. hemipenis, which, when excited, protrude from the cloaca. The female has the ability to store live sperm, therefore, after a single mating, she can produce offspring several times. Cubs are born in different ways. They usually hatch from eggs, but many species of snakes are viviparous. If the incubation period is very short, the delay in oviposition can cause the young to hatch inside the mother's body. This is called egg production. However, in some species, a simple placenta is formed, through which oxygen, water and nutrients are transferred from the mother to the embryo. Most snake nests are very simple, but still eggs are not laid anywhere. The female is looking for a suitable place, such as a heap of rotting organic material, that would protect them from drying out, flooding, sudden changes in temperature and predators. When the eggs are guarded by their parents, they not only scare away predators, but, having been in the sun, they can warm the clutch with their bodies, which develops faster at elevated temperatures. A certain amount of heat is also released when the nest material decays. The number of eggs or cubs produced by a female at a time ranges from a few to about 100 (in oviparous species, on average, more than in viviparous ones). Large pythons are especially prolific, sometimes laying over 100 eggs. Their average number in a clutch of snakes is probably no more than 10-12. Determining the gestation period in these reptiles is not easy, since females can store living sperm for years, and the duration of embryo development depends on temperature. Different types of breeding also complicate the task. However, some rattlesnakes are believed to last approx. 5 months, and in the common viper (Vipera berus) - a little more than two months. The length of the incubation period varies even more.
Life expectancy. The vast majority of snakes reach sexual maturity in the second, third or fourth year of life. The growth rate reaches a maximum by the time of full puberty, after which it decreases markedly, although snakes grow all their lives. The maximum age of most snakes is probably approx. 20 years, although some individuals survived to almost 30. In nature, snakes, like many other animals, rarely reach old age. Many die quite young due to unfavorable environmental conditions, usually falling prey to predators.
MAIN FAMILIES
Modern snakes are usually divided into 10 families. Three of them are very small and include mainly Asian species. The other seven are described below.
Colubridae (already-shaped). This family includes at least 70% of modern snakes, including two-thirds of European species and 80% of those living in the United States. The area of ​​distribution of sagittates covers all warm regions of the continents, except Australia, where they are found only in the north and east. They are also abundant on many large islands in the Old World. The largest number of species lives in the tropics and subtropics. The ungulates have mastered all the main types of habitats: among them there are terrestrial, aquatic, and arboreal species. Many swim and climb well. Their sizes are from small to medium, and the shape is quite varied. Some resemble a thin liana, others are thick, like large poisonous snakes. Almost all of the already-shaped ones are harmless, although several of their poisonous African species pose a serious, if not fatal, danger to humans. In the United States, this family is represented by snakes (Natrix), garter snakes (Thamnophis), pig-nosed snakes (Heterodon), collar snakes (Diadophis), grass snakes (Opheodrys), snakes (Coluber), American whip snakes (Masticophis) (Drymarchon snakes) ), climbing snakes (Elaphe), pine snakes (Pituophis) and king snakes (Lampropeltis). The first four genera are of no significant economic importance. Grass snakes eat some harmful invertebrates. The rest can be considered useful animals, as they destroy rodents and other economically damaging mammals.

Boidae (pseudopods). This family includes about only 2.5% of the species of modern snakes, but among the non-venomous representatives of the suborder, they are the most famous after the already-shaped ones. Boas are usually considered giant inhabitants of tropical forests, but many of them are medium and even small in size, and the habitats are very diverse - up to the Central Asian deserts. The small rubber snake (Charina bottae) from this group is widespread in the western United States and is found even in Canada. All pseudopods kill prey by squeezing it with their bodies, which is why they are usually called boas. However, strictly speaking, boas constitute only one of two subfamilies, and the vast majority of its representatives live in America. The second subfamily of pseudopods - pythons - unites exclusively the snakes of the Old World. In almost all pseudopods, rudiments of the hind limbs are more or less noticeable - in the form of two small claws at the base of the tail. This family includes 6 species of the world's largest snakes; they all live in tropical forests. Only the largest specimens pose a threat to humans. In addition to the anaconda and the common boa constrictor (the only giants of this subfamily), we are talking about 4 types of pythons. In Africa, the hieroglyph (Python sebae) lives up to 9.7 m, in South and Southeast Asia - the reticulated (P. reticulatus) up to 10 m, about the same place - the Indian tiger (P. molurus) up to 6 m, and from the north of Australia to the south of the Philippines and the Solomon Islands, there is an amethyst python (P. amethystinus) up to 7 m long.





Typhlopidae (blind snakes) and Leptotyphlopidae (narrow-necked snakes). These families include approx. 11% of living snakes. They are blind and harmless. They are even often confused with earthworms, but they do not die in dry places. Smooth, shiny scales cover their entire body, including the reduced eyes. Outwardly, representatives of both families are very similar to each other. Both those and others are distributed quite widely, mainly in the tropics and subtropics, although the range of narrow-snakes in the Old World is limited to Africa and South-West Asia, and in the New World they reach the south-west of the United States. Sleephovers inhabit much of the Asian continent and are even found in Australia. This family has 4-5 times more species than the previous one. The length of both is usually 15-20 cm, and only a few are noticeably longer, for example, one African species reaches 80 cm.



Viperidae (vipers). This family includes approx. 5% of modern snakes. They are poisonous and widespread throughout all continents, except Australia, where they are unknown. Of all snakes, vipers have the most effective method of injecting venom into a victim. Their venomous hollow teeth are longer than those of other venomous species, in the "inoperative" position they are laid under the sky, and at the moment of attack they move out of the mouth like the blades of a jackknife. In addition, they are regularly replaced, so removing them does not render the snake harmless for a long time. A viper can hit an animal at a distance slightly less than the length of its own body with one throw. All vipers of the New World and many species of the Old have a deep fossa on each side of the head, which has a high temperature sensitivity, which helps when hunting warm-blooded prey. Snakes with such thermoreceptors are called pit-headed snakes and sometimes stand out in a special family. They are widespread, although absent in Africa. Pit heads are subdivided into 5 genera, one of which includes a single species - bushmaster, or surukuk (Lachesis muta), from the tropics of America. About two-thirds of the remaining species belong to the genus Trimeresurus, which unites mainly tropical snakes (keffiys and botrops), which are widespread in the New and Old Worlds. Other pit vipers are represented by rattlesnakes (Crotalus), dwarf rattlesnakes (Sistrurus), and sardines (Agkistrodon). In addition to rattlesnakes, this group is also inhabited by the water (A. piscivorus) and copper-headed (A. contortrix) snakes in the USA. The area of ​​the former is limited to inland water bodies of the southeastern plains of the country, and the latter is somewhat wider. Rattlesnakes are found in both North and South America. In the United States, they are now found in all states except Alaska, Delaware, Hawaii and Maine, although they previously lived in the west of the latter.
Elapidae (aspid). This family includes about 7.5% of the species of modern snakes. Their relatively short, venomous teeth are fixed on the front of the upper jaw. Bites from large species are dangerous to humans. Almost all terrestrial snakes in Australia belong to the snakes, and more than half of the genera of the family are represented on this continent, and the percentage of poisonous snakes there is higher than on any other continent. However, the bites of many small Australian species do not threaten human death. The most extensive genus of this family - coral snakes (Micrurus) - unites approx. 50 types. Among its representatives, the harlequin coral snake (M. fulvius) lives in the southeastern United States. The most famous among the aspids are cobras (Naja and several other genera), living in Asia and Africa. Especially spectacular is the Indian cobra, or spectacle snake (Naja naja), which, in case of danger, raises the front part of the body and flattens the neck, spreading the neck ribs to the sides, so that a wide hood with a pattern resembling pince-nez is formed. In other cobras, this ability is less developed. African mambas (Dendroaspis) have a reputation for being very aggressive snakes. While some are not fierce at all, all mambas are dangerous as they produce a strong poison. Much less aggressive Asian kraits (Bungarus) are not so well known.



Hydrophiidae (sea snakes). This family includes approx. 2.8% of modern snakes. They inhabit warm coastal waters from South Asia east to Samoa. One species, the bicolor bonito (Pelamis platurus), reaches Africa and the western coast of North America. Sea snakes are closely related to asps and produce a potent poison, but they are rather slow, so they are not so scary. Most of them are morphologically adapted to the aquatic lifestyle: the nostrils are closed by valves, and the tail is flattened in the vertical plane. Few large individuals reach 0.9-1.5 m in length, and the maximum length of sea snakes is 2.7 m.

Collier's Encyclopedia. - Open Society. 2000 .

What are snakes - families and types of snakes in our material. Let's start with the asp family. The family of aspids includes about 180 species. Snakes are common in tropical and subtropical regions of all continents. However, the real country of asps is Australia, where they are most numerous. In length, slate can reach more than 5 meters. The color is extremely diverse, from nondescript brown to a combination of the most "flashy" colors.

In the anterior part of the shortened upper jaw, there are paired venom-conducting teeth. These teeth are noticeably larger than the rest. They are strongly bent back and motionless (unlike the teeth of a viper and a rattlesnake). The poison of asps mainly affects the nervous system. Asps are found in all parts of Australia. As a rule, these are not the largest snakes. Most of them range in length from 50 centimeters to 2 meters. The largest of the Australian snakes (reaching over 3 meters in length) is the extremely poisonous taipan.

What are the snakes of the viper family

What snakes are - click and enlarge the picture!

The viper family consists of 10 genera and about 60 species that are common in Africa and Eurasia. They differ from other poisonous snakes in the most perfect apparatus for introducing poison. It works like a syringe. The short maxillary bone, to which the long, canine-like, venom-conducting teeth are attached, is able to rotate 90 degrees. Inside each of the teeth there is a canal, like in a medical needle. The canal is connected by ducts with paired venom glands. Through the ducts during muscle contraction, the poison flows under pressure through the duct and is injected into the victim's body.

In a calm state, the poisonous teeth lie horizontally along the mouth, with the ends directed backward. The maxillary bone turns before the bite, and the poisonous teeth, moving in a small arc, stand upright. Such a "mechanism" allows, for example, the Gabonese viper, which lives in the tropical forests of the African continent, with a body length of only one and a half meters, to have poisonous teeth 34 centimeters long. Among the vipers, there are many viviparous species, for example, the asp and nosed vipers. There are ovoviviparous forms - in these snakes, eggs mature inside the body. These include gyurza - a large (more than one and a half meters long) viper that lives in Africa and Central Asia.

They live in dry savannas and steppes, in humid tropical forests, deserts, forests of the middle zone, in the taiga. They rise high in the mountains. Most species are terrestrial, but arboreal forms also exist.

What are the snakes boas and false-legged. The family of pseudopods or boas includes about 80 species of boas and pythons. Among them there are quite large snakes (python, anaconda), and small ones, for example, a small western boa, which is only 80 centimeters long. The family was named after the rudiments of the pelvic bones and thighs present in the skeleton of boas and pythons. Males of some species have claw-like outgrowths on both sides of the anus - the remains of the hind legs. In addition, pseudopods are distinguished by the fact that, having caught the victim, they strangle it, twisting around and only then swallow it. Pythons are found in Africa, South Asia, Australia, New Guinea. Boas are more widespread.

What are the sea snakes

Sea snakes are the most venomous reptiles. The reason for the unusually high toxicity of their venom is that the main food of these snakes is fish, which, like all cold-blooded ones, are quite resistant to the effects of poisons. In the front part of the jaws, there are paired poisonous teeth equipped with a venom-conducting channel.

Sea snakes are perfectly adapted to aquatic life - their body is compressed from the sides, especially strongly in the tail; the head is small, covered with rather large shields; the nostrils are closed with valves before immersion. Thanks to the blood vessel-rich oral mucosa, sea snakes are able to absorb oxygen dissolved in water, which allows them to stay under water for a long time. Most species are viviparous (some snakes have a primitive placenta).

Sea snakes can be up to 2.8 meters in length. They are common in the tropical latitudes of the Pacific and Indian oceans. The family of sea snakes includes 16 genera (approximately 50 species), including flat-tails and dove-tails. This group of reptiles is descended from the snakes.

What are the rattlesnake snakes

Rattlesnakes, or pit viper snakes, occupy the same ecological niche on both American continents as vipers in Africa, Asia and Europe. These groups are similar both in the way of life and in the device of the poisonous apparatus.

Rattlesnakes are distinguished from other snakes by the presence of heat receptors located in the pits between the nostrils and the eyes (hence the name "pit-headed"). This organ allows rattlesnakes to find their prey by heat radiation. Thermoreceptors are so sensitive that the snake can detect temperature differences of up to 0.002 ° C.

What are snakes - families and types of snakes

So we told - what snakes are!

We watch the video - what are the snakes and what show can be done even with dangerous reptiles:

POISONOUS SNAKES

Family Aspid (Elapidae). In our country, it has only one representative - the Central Asian cobra (Naja oxiana). The poisonous gland of asps is enclosed in a capsule of connective tissue and is more compact than that of viper snakes. The gland consists of the posterior main (main) lobe; secretory duct and accessory mucous lobe. The main lobe has a complex alveolar structure, in the center of the gland there is a cavity where a poisonous secret accumulates. Secretory epithelium of the serous type. The height of the cells changes depending on the stage of the secretory cycle. Poisonous teeth are motionless (primitive) fixed at the anterior end of the shortened maxillary bone. The structure of the cobra tooth clearly demonstrates the origin of the canal in the tubular tooth by gradually closing the edges of the groove on the anterior surface of the tooth.

Family Viperidae and family. Pit-head (Crotalidae). In the fauna of the CIS, both families are represented, having many common structural features, including a poisonous apparatus. Poisonous glands are located in the temporal region behind the eyes. The functioning part of the gland is a pouch flattened from above in the form of an elongated triangle, which is surrounded by a connective tissue capsule. A massive muscle from the occipital-temporal complex is attached to the capsule from the inside, from above and below. By contracting when the mouth is opened, the muscle presses on the gland, and the poison through the convoluted duct enters the fold of the mucous membrane surrounding the base of the tooth. From here, the poison enters the victim's body through the channel that penetrates the tooth.

The original structure of the poisonous apparatus allows the tooth to rotate about 90 ° around the transverse axis. When the mouth is closed, the long poisonous teeth are in a horizontal position, but when the mouth is opened, the tooth takes a vertical position. The poisonous gland consists of several parts: the main part, which occupies 2/3 of the posterior part of the gland, the primary duct, the bisected accessory gland and the secondary duct leading to the poisonous tooth. The gland has a complex alveolar structure, the secreted secretion accumulates in the central cavity of the gland. A natural bite or artificial production of poison stimulates the activity of the gland, which reaches its maximum 7-8 days after the release of the poison.

In our country, vipers are represented by the common (Vipera berus), steppe (V. ursini), Caucasian (V. kaznakovi), Asia Minor (V. xanthina), nosed vipers (V. ammodytes), as well as gurza (V. lebetina) and efoy ( Echis carinatus). The family of pit snakes has two main representatives of the common, or pallasov (Agkistrodon halys), and eastern (A. blomhoffi) shitomordnikov.

The main difference between pit and viper snakes is the presence of facial pits located between the nostrils and eyes. These pits are thermal locators, with the help of which the snake can easily creep in the dark to motionless or sleeping prey. A temperature gradient is created around the animal, allowing the snake to orient itself accurately. Another feature is the presence at the end of the tail of a kind of rattle, or rattle, formed by a hard leathery cover that remains after the snake molt. In a state of irritation, the snake slightly lifts the tip of its tail and vibrates with it, emitting a dry crackling that is heard from afar. For this, the whole family is sometimes called rattlesnakes.

Poisonous animals and plants of the USSR / B.N. Orlov, D.B. Gelashvili, A.K. Ibragimov. - M .: Higher. shk., 1990 .-- 272 p.