A snake is an animal of the chordate type, class Reptiles, order Squamate, suborder snakes (Serpentes). Like all reptiles, they are cold-blooded animals, so their existence depends on the ambient temperature.
Snake - description, characteristics, structure. What does a snake look like?
The body of the snake has an elongated shape and can reach a length of 10 centimeters to 9 meters, and the weight of the snake ranges from 10 grams to more than 100 kilograms. Males are smaller than females, but have a longer tail. The body shape of these reptiles varies: it can be short and thick, long and thin, and sea snakes have a flattened body that resembles a ribbon. Therefore, the internal organs of these scaly animals also have an elongated structure.
The internal organs are supported by more than 300 pairs of ribs, movably connected to the skeleton.
The snake's triangular head has jaws with elastic ligaments, which makes it possible to swallow large food.
Many snakes are venomous and use venom as a means of hunting and self-defense. Since snakes are deaf, to navigate in space, in addition to vision, they use the ability to capture vibration waves and thermal radiation.
The main information sensor is the forked tongue of the snake, which allows it to “collect information” about the environment using special receptors inside the palate. Snake eyelids are fused transparent films, scales covering the eyes, therefore snakes don't blink and even sleep with their eyes open.
The skin of snakes is covered with scales, the number and shape of which depends on the type of reptile. Once every six months, the snake sheds its old skin - this process is called molting.
By the way, the color of the snake can be either monochromatic in species living in the temperate zone, or variegated in representatives of the tropics. The pattern can be longitudinal, transversely circular or spotted.
Types of snakes, names and photographs
Today, scientists know more than 3,460 species of snakes living on the planet, among which the most famous are adders, sea snakes (not dangerous to humans), pit snakes, pseudopods, which have both lungs, as well as rudimentary remains of the pelvic bones and hind limbs.
Let's look at several representatives of the snake suborder:
- King cobra (hamadryad) ( Ophiophagus hannah)
The most gigantic poisonous snake on earth. Some representatives grow up to 5.5 m, although the average size of adults usually does not exceed 3-4 m. King cobra venom is a lethal neurotoxin, causing death in 15 minutes. The scientific name of the king cobra literally means “snake eater”, because it is the only species whose representatives feed on snakes of their own kind. Females have an exceptional maternal instinct, constantly guarding the clutch of eggs and completely going without food for up to 3 months. The king cobra lives in the tropical forests of India, the Philippines and the islands of Indonesia. Life expectancy is more than 30 years.
- Black Mamba ( Dendroaspis polylepis)
The African venomous snake, growing up to 3 m, is one of the fastest snakes, capable of moving at a speed of 11 km/h. The highly toxic snake venom causes death in a matter of minutes, although the black mamba is not aggressive and attacks humans only in self-defense. Representatives of the black mamba species received their name due to the black coloration of the oral cavity. The snake's skin is usually olive, green or brown in color with a metallic sheen. It eats small rodents, birds and bats.
- Fierce snake (desert taipan) ( Oxyuranus microlepidotus)
The most poisonous of land snakes, the venom of which is 180 times stronger than that of a cobra. This species of snake is common in the deserts and dry plains of Australia. Representatives of the species reach a length of 2.5 m. Skin color changes depending on the season: in extreme heat it is straw-colored, when it gets colder it becomes dark brown.
- Gaboon viper (cassava) ( Bitis gabonica)
The poisonous snake that lives in the African savannas is one of the largest and thickest vipers, up to 2 m long and with a body girth of almost 0.5 m. All individuals belonging to this species have a characteristic, triangular head with small horns located between the nostrils . The Gaboon viper has a calm character, rarely attacking people. It belongs to the type of viviparous snakes, breeds once every 2-3 years, bringing from 24 to 60 offspring.
- Anaconda ( Eunectes murinus)
The giant (ordinary, green) belongs to the subfamily of boas; in former times the snake was called a water boa. The massive body, 5 to 11 m long, can weigh over 100 kg. The non-venomous reptile is found in low-flow rivers, lakes and creeks of the tropical part of South America, from Venezuela to the island of Trinidad. It feeds on iguanas, caimans, waterfowl and fish.
- Python ( Pythonidae)
A representative of the family of non-venomous snakes, it is distinguished by its gigantic size, ranging from 1 to 7.5 m in length, with females being much larger and more powerful than males. The range extends throughout the eastern hemisphere: tropical forests, swamps and savannas of the African continent, Australia and Asia. The diet of pythons consists of small and medium-sized mammals. Adults swallow leopards, jackals and porcupines whole, and then digest them for a long time. Female pythons lay eggs and incubate the clutch, by contracting muscles, increasing the temperature in the nest by 15 -17 degrees.
- African egg snakes (egg eaters) ( Dasypeltis scabra)
Representatives of the snake family that feed exclusively on bird eggs. They live in savannas and woodlands of the equatorial part of the African continent. Individuals of both sexes grow no more than 1 meter in length. The movable bones of the snake's skull make it possible to open its mouth wide and swallow very large eggs. In this case, the elongated cervical vertebrae pass through the esophagus and, like a can opener, rip open the eggshell, after which the contents flow into the stomach, and the shell is coughed up.
- Radiant snake ( Xenopeltis unicolor)
Non-venomous snakes, the length of which in rare cases reaches 1 m. The reptile received its name for the rainbow tint of its scales, which are dark brown in color. Burrowing snakes live in the loose soils of forests, cultivated fields and gardens in Indonesia, Borneo, the Philippines, Laos, Thailand, Vietnam and China. Small rodents and lizards are used as food items.
- Worm-like blind snake ( Typhlops vermicularis)
Small snakes, up to 38 cm long, resemble earthworms in appearance. Absolutely harmless representatives can be found under stones, melons and watermelons, as well as in thickets of bushes and on dry rocky slopes. They feed on beetles, caterpillars, and their larvae. The distribution area extends from the Balkan Peninsula to the Caucasus, Central Asia and Afghanistan. Russian representatives of this species of snake live in Dagestan.
Where do snakes live?
The distribution range of snakes does not include only Antarctica, New Zealand and the islands of Ireland. Many of them live in tropical latitudes. In nature, snakes live in forests, steppes, swamps, hot deserts and even in the ocean. Reptiles lead an active lifestyle both during the day and at night. Species living in temperate latitudes hibernate in winter.
Who is this snake? Perhaps everyone can answer this question without thinking: it is a reptile that crawls on the ground because it does not have legs to walk. Partially is the correct answer. Why partially? Because there are reptiles that are not snakes, but also do not have legs - these are legless lizards. However, our article will not be about them, but about snakes. After all, the group of these animals is incredibly diverse and interesting.
Scientists count about 2,500 snakes in nature. These animals form an entire suborder in the order of scaly reptiles. Snakes are easy to distinguish from other animals by their body shape: it is elongated, as we have already said, snakes have no limbs. The body of these reptiles is flexible; they move along the surface, making wave-like movements. The special structure of the skeleton and the large number of vertebrae make snakes real acrobats, because they can curl up into a ball and even tie themselves in a knot!
The size of the snakes is also amazing in its scope: from a few centimeters to more than 10 meters! We have prepared a separate, very informative story for you about the inhabitants of our planet.
Where do snakes live?
Snakes live on almost our entire planet, with the exception of the icy continent of Antarctica. The greatest species diversity of these animals can be observed in tropical zones. Here snakes reach incredible sizes and there are individuals of a wide variety of colors. They prefer to settle in forests, deserts, swamps, mountains, steppes, as well as in fresh waters.
Lifestyle, nutrition and behavior of snakes in nature
By way of life, all snakes are loners. However, during the mating season, massive concentrations of these animals can be observed, especially during the mating period.
Many of the snakes are deadly poisonous. Especially many of these snakes are found in Africa and Asia. This video will tell you about the world:
As for the sense organs of snakes, they do not have excellent hearing or good vision. The thing is that snakes completely lack an external ear, so the snake “hears” almost only due to the vibrations of the soil or the surface on which it is located. The eyes of snakes are not distinguished by vigilance; they are able to notice only what is constantly moving; in most cases, snakes do not pay attention to motionless “prey”.
If vision and hearing are naturally poorly developed in these reptiles, maybe the taste buds in snakes are excellent? Unfortunately, the situation here is exactly the same. Snakes do not distinguish the taste of the food they eat. In general, they do not particularly enjoy eating food in the usual sense; they do not chew it, but swallow it whole.
The only sense that snakes have well developed is their sense of smell. These reptiles have receptors that detect odors not only in their nostrils, but also on their long tongue. Therefore, snakes often stick out their tongues to smell the scent of their future prey.
Snakes are also endowed by nature with so-called thermolocators. These are special devices located on the muzzle and looking like dimples. Scientists believe that such receptors allow the snake to see the world around it as if through a thermal imager.
The voice of snakes is not developed; the only sound that these animals have learned to make in the process of evolution is hissing. The only exception is, perhaps, rattlesnakes, which know how to make a “rattle” from their tail: they have scales located in a special way in this part of the body.
One of the characteristics of snakes is molting. The fact is that sooner or later the snake grows out of its scaly shell and needs to be “replaced”. However, each scale does not change individually in a snake; the animal sheds the old “skin” with a stocking. The dropped “outfit” is called a crawl.
Snakes have a wide variety of colors: from modest and inconspicuous to incredibly bright and colorful. Some use skin color to hide from enemies or to sneak up on prey unnoticed. Others, on the contrary, warn with their color that it is better not to approach them. As a rule, all venomous snakes have bright scales, but there are exceptions.
All representatives of the suborder of snakes are predatory animals. Some eat mice, others eat lizards, others eat only smaller ones, others dine on bird eggs, and others... can even eat a whole crocodile!
Often the prey of snakes (naturally, very large ones) are large ungulates. The snake literally pulls itself onto the carcass of the caught animal and gradually swallows it, and then digests it for a long time.
Internal structure of a snake
Since the snake’s body is long and narrow, all organs located inside the body must have corresponding sizes, therefore all the internal organs of the snake are very long. Their placement is also peculiar. In many snakes they are located asymmetrically, and in the most highly organized snakes, paired organs have become unpaired. Worm-like snakes, for example, have two lungs, but the right one is always larger than the left. In more highly organized snakes, the left lung is absent, the right is well developed, and in snakes such as vipers, as compensation for the atrophied left lung, the back of the trachea expanded and formed the so-called tracheal lung. The back of the preserved right lung has a very thin wall, the tissue of which can stretch well. This helps the snake swell when it inhales, visually increasing its body size to scare off enemies, and when it exhales, it makes a loud warning hiss.
The esophagus of snakes is quite long and is a tube with very powerful muscular walls that can flatten and push food into the stomach. The stomach of snakes also acquired an elongated shape, but the intestines became shorter. Some snakes have slightly wider bodies and stomachs than most other species. This allows them to feed on larger prey.
The kidneys of snakes are paired, very long and narrow. The right kidney is moved closer to the head, and the left kidney is moved closer to the tail. There is no bladder, and the ureter opens directly into the cloaca.
The reproductive organs are paired, in females they are represented by a pair of ovaries, and in males - by elongated testes and a kind of copulatory organ. This organ looks like two sacs equipped with small spines. The sacs are usually located under the skin behind the anus and can be detected by probing with a thin wire. During mating, the male turns the copulatory organ outward and inserts it into the female’s cloaca.
Features of the blood supply of snakes
R. Seymour (University of Adelaide, Australia) and H. Lillywhite (University of Kansas, USA) studied the blood supply systems of nine species of snakes. Significant differences in these systems have been established depending on the lifestyle characteristic of a given species. Thus, the blood pressure of snakes living in trees reaches 74 millimeters. Herpetologists know that such snakes remain in an upright position for a long time, in which the blood supply to the brain naturally requires significant effort from the body. In water snakes, which remain in a horizontal position for a long time, the blood pressure does not exceed 22 millimeters of mercury. A certain pattern was also established in the location of the heart. In all land species of snakes it is located closer to the head, and in water snakes it is almost exactly in the middle of the body.
Glands
In addition to the glands that make up the snake's venomous apparatus, there are also skin glands on the snake's body. Some snakes use the poisonous or foul-smelling secretions from these glands to ward off predators. For example, in a beautiful Far Eastern snake - the tiger snake - similar glands are located on the back in the front part of the body. They secrete a yellowish secretion that irritates the mucous membranes. If a dog grabs such a snake, he will immediately throw it away and begin to shake his head, trying to get rid of the burning sensation in his mouth. In the skin of snakes there are areas of the so-called glandular epidermis, which secrete fatty substances that lubricate the scales and thereby facilitate their gliding when crawling. In addition, these substances have a specific smell (which, probably, was felt by anyone who held snakes in their hands). Thanks to this, the crawling snake leaves an invisible scent trail, which helps individuals of the same species find each other.
Nervous system
The brain of snakes, located in a durable bone capsule, is relatively small, so higher nervous activity in snakes is poorly developed. The spinal cord, on the contrary, is very large and well developed, which ensures excellent coordination of the snake’s movements, lightning-fast reactions, and precision muscle control. For example, a yellow-bellied snake, which is given several rodents in its terrarium, is capable of taking three or four mice at a time. He grabs one rodent with his mouth, strangles the second with a ring in the upper part of the body, and presses the third and fourth to the walls of the terrarium, bending the middle and rear parts of the body.
You might think that a snake is all long tail topped by a head, but in fact the tail is only 20% of the snake's body.
The word vertebra is translated from Latin as “vertebra”. Humans have thirty-three vertebrae, together they form the spinal column and the bones in the neck. A snake, depending on the species, can have more than ten times more of them. From most of these vertebrae the snake's ribs grow. Like humans, a snake's head has no ribs. And at the other end (again, like in humans), where the ribs end, the tail begins. The human “tail” is called the coccyx; in the case of a snake, the tail begins behind the cloaca.
All reptiles, amphibians and birds have a cloaca. It is named after the Cloaca Major (also known as the Great Cloaca, or Cloaca Maxima), an ancient sewer system in Ancient Rome that ran through the Forum. In snakes, the cloaca is a small opening on the underside of the body, the reptilian equivalent of the butt. So a snake's tail, like a lizard's or a pheasant's, starts behind its butt.
Although, like mammals, the tail of snakes is controlled by sphincter muscles, it differs from the anus of mammals in that it provides a single passage for both urine and feces. This passage is also used for mating and egg laying. In males, it contains both penises (known as hemipenises, or "half-penises"). When mating, the male turns each of them inside out, so that they stick out from his cloaca. Externally, the hemipenis resembles an exotic mollusk, decorated with cones, spines and tubercles. Each one in turn is inserted into the cloaca of the female, whose design is “tailored” specifically to him - in order to ward off strangers, representatives of other species of snakes.
Recent research has revealed that, although the snake cannot be classified as “right-handed,” from the point of view of the penis, this definition is applicable: on the right side, the hemipenis is usually larger, and it is the one that is inserted into the female first. Another area of application for snake cloaca is “farting”. The air is pushed out of the cloaca by a burst of sharp pops, indistinguishable in timbre and volume from a high-pitched human fart. An unpleasant odor (plus the effect of surprise) helps snakes scare away predators.
If a snake is placed in too small a space, it may mistake its tail for an enemy and pounce and swallow it. There are cases of snakes choking to death on their own tail.
Ouroboros (translated from Greek as “devouring its own tail”) is an archaic symbol: a snake coiled and biting its own tail. This motif is found in the mythology of the ancient Egyptians, Greeks, Scandinavians, Hindus and Aztecs and symbolizes the cyclical nature of things. In the Timaeus (360 BC), Plato attributes the origin of life in the universe to such a ring-shaped, self-devouring being, and the Swiss physiologist Carl Jung (1875–1961) considered it an archetype - “the primary innate structure of the collective unconscious.”
Ouroboros helped solve one of the greatest scientific mysteries of the 19th century: the chemical structure of benzene. First discovered in crude oil, benzene is a powerful solvent; It is used in the production of dyes and plastics. Benzene was isolated in 1825 and was initially used to remove paint, as an aftershave lotion and to extract caffeine from coffee - until it was discovered to be dangerously toxic. And although the chemical formula of benzene, C6H6, had been known for a long time, no one could explain its molecular structure. This continued until the German chemist August Kekule (1829–1896), after many years of work, came up with the idea that this was a ring of six carbon atoms. Each of them is connected to a hydrogen atom by a simple bond, but they are connected to each other by both simple and double bonds, which constantly change places.
Kekule's hypothesis transformed organic chemistry. And he dreamed of the insight in reality - in the form of an image of a snake with its own tail in its mouth.
ALAN: When I was little, there were rattlesnakes on TV all the time, every week. In the 70s it was, like, something out of the ordinary. Every week, on all channels, they always played rattlesnakes. And now not one at all.
