Snakes - all what I know
Introduction : Ever since I can remember, I have always been fascinated by snakes. So secretive, wonderful and so dangerous. Some people admire them, while others hate them. I did a lot of research on them as well, read, and here is this blog as a result. Snakes inhabit almost the entire globe, but there are none in Ireland. Ireland is not the only place on earth without these cold-blooded reptiles. There are no indigenous species in Iceland, Greenland, Hawaii, New Zealand, in the northern parts of Russia, in Antarctica and in some parts of Canada... Legend says that Saint Patrick threw them into the sea, and scientists claim that they never existed in Ireland, because there are no fossils or any other remains...
Probably no animal species arouses in people as many different feelings as snakes. Snakes evoke fear and disgust in most people in Western, industrialized societies. However, many tribes in Africa and Asia consider the snake a symbol of fertility and birth, and in some places, a deity.
Many scientists in the world study the biology of snakes, especially their ecology, behavior and physiology. A special branch of research is the study of snake venoms. Ophidism (poisonous snakebite and its consequences) is still a significant cause of death in some parts of the world. In addition, some biologically active substances from snake venoms are used to treat some pathological conditions in humans (for example, to break up blood clots in blood vessels that are responsible for heart attacks or strokes).
People have always lived with snakes, feared them or worshiped them, looked for a way to protect themselves from them or use them. There are countless traditions and legends about snakes. In any case, snakes aroused, and still arouse the attention of scientists and the ordinary world. Every day we learn something new about them, but despite that they always remain a mystery.
Classification of snakes
Snakes belong to the class Reptilia, subclass Lepidosauromorpha, order Squamata, and suborder Serpentes. Apart from snakes, reptiles with beaks also include lizards (Sauria) and Amphisbaenia.
The systematic classification of snakes has not yet been completed. Of all reptiles, snakes are the least taxonomically treated. This is especially true of the Colubridae family.
The suborder of snakes is divided into the following families:
1. Anomalepidida
2. Leptotyphlopida
3. Typhlopidae
4. Loxocemidae
5. Xenopeltidae
6. Aniliidae
7. Uropeltidae • Cylindrophiinae • Uropeltinae
8. Boidae • Boinae • Erycinae
9. Pythonidae
10. Tropidophiidae • Ungaliophiinae • Tropidophiinae
11. Bolyeriidae
12. Acrochordidae
13. Colubridae
General characteristics of snakes
Snakes have a very elongated, round body covered with horny scales, which ends in a thin tail. Their head is ovoid or triangular in shape, in some species it is quite vaguely separated from the body. They have no external limbs and no bladder. However, their exceptional mobility is ensured by a highly developed spine. Also, their ribs, like the spine, are well articulated, which enables them to move more easily due to the lack of legs. They also have a very developed muscle musculature, so it is easy for them to move forward and backward. The auditory bone is well developed, but without the eardrum and auditory canal. Snakes receive sound waves through the substrate. The left lung is very stunted, while in some species it is completely absent. The eyelids have fused into a transparent protrusion, hence the rigid gaze of snakes. The tongue is long and forked, and serves as an organ for the sense of touch and the sense of smell. The brain is poorly developed and stunted compared to the highly developed spinal cord. The jawbones are long and mobile, so the snake can open its jaw wide and swallow prey larger than itself. The esophagus and stomach are also very stretchy. Some snakes first drown their prey and then swallow it, while others, venomous, first poison their prey and only when the poison starts to work, do they switch to swallowing. An exception is the white-tailed deer, which swallows its prey alive. Their teeth are very sharp and slightly curved, and they are used for catching and holding prey. In venomous snakes, the teeth are hollow and through them the venom of the gland is injected into the body of the victim. Venoms as a poisonous apparatus have poisonous glands, which secrete poison, muscles, with which it is squeezed out, and channels inside the teeth, through which the poison is injected into the victim's body. Snakes do not shed their scales, but change their horn cover (snake coat) several times a year. All snakes are carnivores and are very voracious. Small species feed on earthworms and insects, and larger species feed on vertebrates. Some eat only eggs. They can last a very long time without food (even for a year). Males have paired copulatory organs. As a rule, snakes reproduce by eggs, except for some species that give birth to live young. They do not have a voice, and hissing occurs due to the sudden expulsion of air through the larynx. They are spread all over the world, but they are most abundant in tropical and subtropical regions. The reason for this is the inability to regulate their own body temperature, so they usually stay in areas where the lowest winter temperature is above 18 degrees Celsius. There are them on land and in water.
Venomous snakes
There is a big difference between venomous animals and venomous animals. Poisonous animals are also called cryptotoxic, and have one part of their body poisoned (eg some types of fish), and do not have specialized organs for injecting poison into the victim's body. Venomous animals (phenerotoxic) differ from poisonous animals in one small but very important feature. Venomous animals have glands in their bodies that secrete poisons, but more importantly, they have organs specialized for injecting poison into the victim's body. In this way, poisonous animals defend themselves from attackers or catch prey. Venomous snakes belong to this group of animals, and their specialized organ for injecting venom is the teeth.
Of the approximately 3,000 species of snakes that live on Earth today, 10 - 12% (approximately 300 - 360 species) are dangerous for humans, and several hundred species are poisonous, but harmless to humans. Since snakes, like other reptiles, cannot regulate their own body temperature, they are most numerous in tropical and subtropical areas where the lowest winter temperature does not fall below 18 degrees Celsius. It is interesting that on every continent the number of non-venomous snake species exceeds the number of venomous species. The exception is Australia, where the number of poisonous species is far greater than non-poisonous ones. In addition, snakes live in Australia, whose venom is considered the most toxic of all snakes.
There are two families of venomous snakes:
1. Elapidae (adders) i
2. Viperidae (vipers and pit vipers).
The viper family includes cobras, mambas, coral snakes, Australian venomous snakes, sea snakes, and some other snakes from Asia and Africa. European, Asian and African buttercups, rattlesnakes, and South American and Asian pit buttercups belong to the buttercup family.
Structure of the poisonous apparatus
The structure of poisonous teeth and poisonous apparatus is different in adders and scorpions. In adders, poisonous teeth are located on the front part of the upper jaw. They are immobile and, when the mouth is closed, are located in a skin fold in the lower part of the oral cavity. In addition, the teeth of many vipers do not have a hollow channel inside the venomous teeth, but their teeth are deeply grooved. The venomous teeth are connected to the venom glands that produce the venom. When a snake like this bites, poison flows from the gland through the tooth (or groove) into the wound. Some African and Asian cobras have special adaptations. Due to the special structure of their poisonous teeth, they can spray poison at a distance of up to 3 meters and thus defend themselves against attackers. The poison has a strong irritating effect on the eyes and, if not washed away immediately, can lead to permanent blindness. Four species of African cobras are especially known for this feature. These are the black-necked cobra (Naja nigricollis), the Mozambique cobra (Naja mossambica), the red cobra (Naja pallida) and the ringhal (Hemachatus haemachatus). And some species of Asian cobras can also spray venom.
Hornbills and pit vipers have the most developed venomous apparatus and teeth. In them, the teeth are also located in the front part of the upper jaw and look like injection needles, but they are mobile. When not in use, the teeth are folded back in the mouth and covered by a protective fold of skin. During a bite, the teeth are straightened and the poison from the venom gland flows through the dental canal into the wound.
Pit vipers also have special organs located in the pits between the nostrils and the eyes. These organs are thermoreceptors and the snake uses them to find warm-blooded prey in the dark. These organs are among the most sensitive receptors in the animal world and can register a temperature difference of 0.001C. It is still not known how the snake's brain reconstructs the thermal image created by these organs.
Apart from the families mentioned above, some snakes from the Colubridae family are also poisonous. This family includes 60% of all snakes and includes many non-venomous snakes (all of our non-venomous snakes belong to this family). In that family, however, there are several species of snakes that have grooved venomous teeth that are located at the back of the upper jaw and cannot be bent like those of rattlesnakes or pit vipers. When biting, the snake must firmly bite the prey and at the same time make movements with its jaws as if it were chewing in order to bring the prey to the rear poisonous teeth and introduce the poison into the victim's body. Most of the poisonous snakes of this family are not dangerous to humans, but there are a few species that can cause harm with their bite. Bites by boomslang (Dyspholidus typus) and the so-called bird snakes (genus Thelotornis) are deadly to humans. The well-known American herpetologist Karl P. Schmidt died from a boomslang bite, and the German herpetologist Robert Mertens died from a Thelotornis kirtlandii snake bite.
Often people ask the question: "Which snake is the most poisonous?". This question should perhaps read: "Which snake bites the most people annually?"
Namely, there are very poisonous snakes that live in areas where few people live, so they almost never come into contact with them. A good example of this is the desert taipan snake (Oxyuranus microlepidota), which lives in the desert areas of Australia.
This snake has the most toxic venom of all known snakes. However, it lives in remote desert areas and is not aggressive, so there are almost no human casualties caused by the bite of this snake. Many more people are bitten by snakes in areas that are densely populated or where snakes approach houses or barns attracted by large numbers of rodents, which are the main food for most snakes. In addition, death from snakebite is also dependent on proper medical attention and care after the bite has occurred. Many areas of Africa and Asia where people and poisonous snakes live close to each other are far from major medical centers, so there is no quality medical care. It is very difficult to determine exactly how many people die each year as a result of bites, because many places where they most often occur are remote and information about bites never reaches the public. In general, snakebite mortality is very low in areas with well-developed medical care (for example, the US, Australia, and Europe), and high in underdeveloped areas of Africa, Asia, and South America. Although it is difficult to say which snakes most often kill people, it is possible to indicate which snakes are the most dangerous in certain parts of the world.
Snakes of Europe
In Europe, relatively few people die from snake bites. The reason is that there are no such dangerous and poisonous snakes in Europe as, for example, in Africa or Asia. In addition, medical help and care are readily available in almost all parts of Europe, so it is possible to begin treatment for bites before life-threatening symptoms develop.
In Europe, only dangerous venomous snakes from the buttercup family live. Most European stingrays are very small (many are less than 60 cm), so if they do attack and bite, the amount of poison injected is very small. All European stingrays have a poison in which hematotoxic substances predominate. They cause disorders in the number of blood cells, disorders in the blood clotting mechanism, and instantly destroy tissues. After the bite, there is pain and swelling that quickly spreads from the bite site. Blisters filled with a clear liquid also appear at the site of the bite and in its surroundings. If a large amount of poison is injected, and the bite is not treated, gangrene can occur as one of the complications (although very rarely). The most common bites are on the fingers or toes. Bites to the head, neck or blood vessels are particularly dangerous.
In Europe, people are most often affected by the viper (Vipera ammodytes), the viper (Vipera berus), the Italian (Vipera aspis) and the Spanish viper (Vipera latastei). Of all of them, the viper is the most dangerous.
The Vipera ammodytes is also Europe's largest poisonous plant. Females grow up to about 60 cm, but males can grow up to 1 m. In some populations, there is a noticeable difference in color between males and females. Males are ash gray, and females are usually brown, grey-brown or red-brown.
There is a characteristic "zig-zag" line on the back, which is broken in some specimens, forming rhombuses. At the top of the viper's snout is a small horn. The viper feeds on lizards, small rodents and birds. It mates in the spring, and in the fall the female gives birth to 3 - 10 (sometimes more) live cubs. It is not aggressive and if disturbed, it will not immediately attack, it will just hiss and try to run away. It is often necessary to provoke him strongly in order to bite. If, however, an attack occurs, it is necessary to seek medical help, because the viper's bite is very poisonous. The first symptoms of poisoning are pain and/or swelling of the bitten part of the body. Swelling occurs 2 - 3 minutes after the bite and spreads quickly. In large specimens, the teeth can be an entire centimeter long, so the poison can be introduced deep under the skin or even into the muscle, which accelerates the development of poisoning symptoms. Because vipers are easy to maintain and breed in captivity, they are often used as a source of venom for the production of antiserum.
Vipera berus is the most widespread snake in Europe and the most widespread snake in general. It extends over the whole of Europe, through Russia all the way to the coast of the Pacific Ocean. In Sweden, it can also be found in the Arctic zone. It is not found in southern Spain, southern Italy, the south of the Balkan Peninsula, and some larger Mediterranean islands. It is one of the few snakes whose biology has been well studied. Likes wetter habitats than vipers. Unlike the viper, it is more often found in lowlands, near ponds or swamps. In the Alps it can be found over 2000 meters above sea level. In autumn, she gives birth to live cubs. The stingray's venom is not as strong as the viper's venom, although more severe tissue damage may occur in some individuals. Symptoms of poisoning are pain and swelling. The bite of a red fox is generally not fatal to a healthy, adult person. However, the help of a doctor is recommended.
Snakes of Asia
RUSSELL'S buttercup In Asia, probably the most people suffer from sand effe and Russell's buttercup (Daboia russelli). It is common near villages and is active at night. That's when most attacks happen, because many people in India walk barefoot. The poison destroys tissues and blood cells, and an untreated bite usually has a fatal outcome.
Kraits (genus Bungarus) are also very dangerous snakes. Kraits are generally no longer than 1 m, but they have an extremely toxic poison that affects the nervous system. They are contrastingly colored: most often they are black or dark brown with yellow, white or reddish transverse stripes. The behavior of the striped krait (Bungarus fasciatus) is interesting.
Although people die from Indian cobra bites (Naja naja), the number of people bitten is relatively small compared to the size of the cobra population and the human population. The reason is that the cobra is considered the embodiment of some Indian deities, so many people are careful not to disturb or harm cobras. Even somewhere (for example, in the town of Shigali) snake festivals are held. People collect cobras before such events and carefully return them to the place where they were found after the festival.
KING COBRA The king cobra (Ophiophagus hannah), which is the most venomous in the world, lives in South and Southeast Asia. Specimens with a length of 4.5 m are not rare. Since it lives exclusively in forest areas, it rarely comes into contact with humans, so the number of bites of this snake is very small. Snake charmers in Burma and Thailand who use these snakes for their performances are most often bitten. The bite is very dangerous, because the cobra bites a large amount of strong poison. A case was recorded when a king cobra bit an elephant in the fold of skin at the top of the trunk, and the elephant died within a few hours.
Snakes of Africa
Bitis arietans It is assumed that a very large number of people suffer from the bite of the hissing beetle (Bitis arietans). The viper is quite a slow and clumsy snake, but it has a very fast attack. It most often approaches human settlements because there are many rodents that it feeds on. It often makes its presence known with a loud hissing sound, which is how it got its name. It is very widespread in Africa south of the Sahara and is common near human settlements. The poison is very toxic and causes death in a large number of untreated cases.
Echis carinatus However, the most dangerous and probably the biggest killer of all snakes is a small snake called the sand echa (Echis carinatus). The sand ephah is distributed throughout Africa, the Middle and Middle East, and Asia as far as India. It often lives near human settlements and in colonies, so where one is found there are probably many others. Tony Phelps in his book "Poisonous Snakes" states that this snake probably kills the most people of all snakes. This is due to its large area of distribution, frequent life near people, and the fact that, although small (the largest specimens reach barely 60 cm), it has a very toxic poison. There have been recorded cases of death from the bite of an effe about 20 cm long. Efa is not timid and does not run away, but takes a characteristic defensive stance. She quickly begins to twist her body so that her scales scrape against each other. Since there is a small ridge on each scale, scraping creates a special sound, characteristic of this snake. The poison is extremely toxic to humans. It causes bleeding from all mucous membranes and prevents blood from clotting so that it is possible to bleed from, for example, wounds caused by shaving. Apart from this, the poison also causes severe tissue damage. Despite proper treatment, subsequent complications of the venom are very common, so death can occur 15 days after the bite.
Although the above-mentioned species kill the most people, the inhabitants of African villages fear the black mamba (Dendroaspis polylepis) the most.
The black mamba is considered the most dangerous snake in the world. It grows up to 3 m in length (some extremely large specimens up to 4 m!), and is very fast and aggressive. Although there are stories that the mamba can overtake a car in fast driving, precise measurements have shown that the mamba cannot move faster than 20 km/h, although that is a very high speed for a snake. Although individual specimens differ in their aggressiveness, males are most aggressive in the spring when they defend their territory from other males. Then even approaching a mamba within 10 meters can have fatal consequences.
Namely, the mamba differs from other snakes in that it often has the habit of attacking first without any reason. During the attack, the mamba often raises the front part of the body high above the ground, so bites on the head and neck are not rare in humans. At the same time, it approaches the victim at high speed, half-opened mouth and deep hissing. Experienced snake hunters say that then you should immediately throw yourself aside, because the mamba does not turn when attacking and (most often) does not repeat an unsuccessful attack. Therefore, it is best not to approach a black mamba in an area that is not open (for example, in a forest). The end of the attack can sometimes be so fast that the victim is bitten 5 - 6 times within 3 - 4 seconds, without even noticing where they have been bitten. Because the mamba is very large, it injects a large amount of highly toxic venom that affects the nervous system - it stops breathing and prevents swallowing. The venom is fast-acting, so treatment with snake antiserum should be started within a few minutes of the bite. Untreated cases have a 100% mortality rate.
Three species of green mamba live in Africa. They are most common in forest areas that are not densely populated, so they are likely to bite fewer people. In addition, unlike the black mamba, they are not so aggressive and fast.
Snakes of North America
There are 19 species of venomous snakes in North America: 15 species of rattlesnake, water moccasin, russula, and two species of coral snake. Rattlesnakes, rattlesnakes, and water moccasins are pit snakes, and coral snakes belong to the Elapidae family. Of all of them, the most famous are rattlesnakes.
THE RATTLER They are significant because they have the so-called tail tip. a rattle that no other snake species has. The rattle consists of loosely joined dry segments of skin that the snake does not discard when changing its coat. When started, the segments create a special sound, characteristic of rattlesnakes. A newborn rattlesnake does not have a rattle, but after 3-4 changes it can already use it. The loudest are the ratchets that have 8 - 11 segments. By the number of segments, it is not possible to determine how many times the snake changed its coat in its life, because the segments from the top of the rattle often fall off, so the ratchet can be shorter or longer regardless of the number of changes.
EASTERN DIAMOND CEGRTUS Rattlebells can be of different lengths. The largest species can be over 2 m long, and the smallest about 60 cm. They live in the most diverse habitats, from deserts to subtropical swamps. The largest of all is the eastern diamondback rattlesnake (Crotalus adamanteus).
The largest specimen caught was about 2.4 m long. She lives in Florida and several neighboring states. It got the name diamond because it has numerous square patterns on its back that resemble diamonds in shape. If you approach her, she will start hissing loudly and use a ratchet, but she always tries to escape to any shelter. Its venom is not very toxic, but the injected amount is very large and, if the bite is not treated, it usually results in death. It does not like the presence of people and avoids staying near them, but due to the large land reclamation and cultivation of large areas of Florida, it is more and more often forced to do so, and people are more and more exposed to attacks by this snake. That's why an action was launched in America to preserve this endangered species of snake.
The western diamondback rattlesnake (Crotalus atrox) grows up to 2 m, and inhabits large areas of Texas, New Mexico, Arizona, and Arkansas. It is similar to the eastern diamondback rattlesnake, but smaller and less intensely colored. In addition, it avoids wetlands and lives in dry steppes and semi-desert areas. Unlike its eastern relative, this rattlesnake does not run away but faces the attacker. Due to its high aggressiveness and the area it lives in (high population density), the western diamondback rattlesnake is considered one of the most dangerous snakes in the United States.
The wood rattlesnake (Crotalus horridus) is the only species of rattlesnake that lives in the densely populated northeastern United States. It is probably the first species of rattlesnake encountered by the first American settlers. It lives in forest areas, but also near rivers and lakes.
Crotalus horridus
She is not particularly aggressive and needs to be provoked a lot in order to attack. This type of rattlesnake is also endangered, because its habitats have been destroyed a lot in the past decade. This type of rattlesnake is used in their rituals by the followers of the Church of Jesus Christ. Bites in the circles of followers of this sect are very common, but they most often do not seek any medical help, so the number of injured people is very high.
All North American rattlesnakes (except one) have a venom dominated by chemotoxic substances. The poison has a very destructive effect on tissues and can cause gangrene. The main symptoms are pain and rapid swelling of the bitten part of the body. Sometimes there are also symptoms associated with the neurotoxins in the poison (change in color perception, changed taste and smell, etc.). The appearance of blisters on the skin that are filled with clear and/or bloody contents is also common.
In the southern parts of the USA, the water moccasin (Agkistrodon piscivorus) lives along rivers and lakes.
WATER MOCCASIN
It grows up to 1.5 m, and in some places it can be very common. For example, Florida swamps are full of water moccasins. It feeds mainly on frogs and fish, but also hunts small rodents. It can often be confused with water snakes. It is most easily recognized by its characteristic behavior. When a person approaches the shore, all non-poisonous snakes run into the water. The water moccasin, however, does not run away from humans. Bites from this snake are very common in the southern states of the USA. The venom has a strong proteolytic effect and can cause severe tissue damage. However, deaths are very rare today.
The ruffed grouse (Agkistrodon contortrix) is widespread across the eastern United States all the way to Texas.
RED HEAD
It most often inhabits hilly forest areas in the north, but in the south it is also common in swampy lowlands. In the eastern US, it can often be found in gardens and orchards around houses where it comes from neighboring forests. Since the red-headed beaver is protectively colored, it is very difficult to recognize it on the forest floor, so the number of people bitten in the eastern USA is very high. Bites are especially common during the weekend, when many families go out into nature. Symptoms of a bite are pain and swelling. The bite of a ruffed grouse is not dangerous for a healthy, adult person. However, it is recommended to see a doctor, because the poison can also have a strong proteolytic effect.
Water moccasin and russula have hemotoxic poisons, so their action is similar to that of rattlesnakes in this climate.
Snakes of Australia
In Australia, the number of venomous snake species far outnumbers the number of non-venomous snake species. snakes with the most toxic venom live in Australia, but these snakes do not live near populated areas, so there are almost no human victims. Only poisonous snakes from the Elapidae family live on this continent. There are also several species of very dangerous snakes that often come into contact with people.
One of the most dangerous Australian poisonous animals is the taipan (Oxyuranus scuttelatus), which grows up to 3 m. It is distributed in the northern and northeastern areas of Australia, in the area of tropical climate.
TAIPAN
Avoids desert and semi-desert areas. The taipan excretes a small amount of highly toxic poison with its bite. The poison of the taipan is twice as strong as the poison of the king cobra, and it affects the nervous system: it causes paralysis, disorders in blood clotting and damages muscle fibers. Experiments have shown that the poison obtained from one bite can kill several million mice. After the bite, it is necessary to start treatment with a special snake antiserum as soon as possible, because permanent paralysis and muscle damage occur very quickly. Fortunately, there are not many people living in these areas, so attacks and bites are relatively rare. Mortality from untreated bites is around 80%.
The tiger snake (Notechis scutatus) lives in southern and southeastern Australia.
SNAKE TIGER
Since these are the most densely populated parts of Australia, this snake is often in contact with humans. In the suburbs of Sydney and Melbourne, it is often found in gardens. It grows up to 1.5 m, and has a very neurotoxic poison that causes muscle damage and blood flow disorders. Mortality from untreated bites is about 45%. The related snake Notechis ater lives in the same area and in Tasmania and the surrounding islands. The poison has the same toxicity.
