Snake
A picture showing the areas where snakes spread around the world
Snakes are elongated, limbless reptiles of the suborder Serpentes, like all other squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales; they have no limbs, no outer ears or eyelids, but there are edges in their bodies, which are believed to represent their faded limbs. The carnivorous snakes have 2,700 species on earth, spreading across all continents, except Antarctica. They are found in various lengths from 10cm to several meters for large snakes, such as origin and anaconda, which may be more than 7 m long, most snake species are non-toxic, and toxic species mainly use their toxicity to kill or subdue the prey, as a small amount of snake poison is sufficient to cause severe damage to the victim or even cause death to man.
General Features
The snake, like all other reptiles, has its body covered with sheets of corneal material, but it differs by its ability to skin the crust cover of its entire body from time to time; the skeleton of most snakes is composed of the skull, spine and ribs; the composition of the snake’s skull combines rigidity and flexibility as its brain is well protected by a strong bone cover while its jaws are highly flexible and the lower jaw contains flexible ligaments as it expands to allow it to swallow preys of various sizes; the spine of the snake consists of many vertebrae but in any case they are at least 200 vertebrae and not more than 400Vertebrae, of which the number of tail vertebrae constitutes a small percentage of the total number of vertebrae; the snake vertebrae are well connected and each Vertebra allows for increased muscle strength since it uses its body in movement instead of limbs, but with regard to the tail, its tail is coherent with its body as the snake does not have the characteristic of giving up the tail when necessary as some lizards do, including geckos for example.
Sensual abilities
• Vision: Snakes have a variety of visions; some have poor eyesight and others have either good or sharp eyesight, and it is noted that snakes living on trees have better eyesight than those living in burrows or underground, and some snakes can focus on one point center, such as the poisonous Asian snake Ahaetulla.
In general, it can be said that snakes do not have good vision, but most possess enough sight to perceive their nearby environment or to tail their preys.
• Smell: The sense of smell is the serpent’s main guide to move and discover its surroundings but it does not rely on the nose in the performance of this task, and instead snakes depend on their tongues to taste and smell. When it goes out to hunt, it takes its tongue out of the hyoid bone and moves it in the air, it then happens to pick atoms of odors and analyzes them, recognizing surrounding and locating preys, with the aid of the so called Jackson member, which analyzes different odors and sends them to the brain, the aforementioned organ is located above the snake’s gums.
• Hearing: snakes lack external ears, though they do have internal ears that can pick up ground-borne vibrations; The underside of a snake is very sensitive to vibration, allowing the snake to detect approaching animals. Some snakes can use their infrared-sensitive sensors, between the eyes and the nose, which can sense the surrounding surface temperature, and detect and stalk its prey’s temperature.
Breeding
The female snake is known as a viper, but the male is known as a serpent, and snakes generally breed in the spring and summer, when the female snake releases pheromones that attract males to mate, as it is not known exactly how the female chooses the male, but it is noted that males make a circle around the female in the so-called mating circle and then the female chooses a male from them, and the circle group go away except the chosen male which crawls under the female and impregnates it.
Snakes lay eggs in two manners, the first is that the female lays eggs ranging from 2 to 100 eggs according to the snake species in a safe place, and the eggs hatch after one or two months, while in the second case some snakes tend to keep eggs in their bodies, thus giving birth after eggs hatch inside as for parental care, most snakes leave their eggs in a safe place, not caring, and embryos crack the eggs with a frontal tooth, breaking it from inside and then the aforementioned tooth falls the moment they step out of their cradles, when snakelets set foot in the outer world, they manage their way without parental care, dispersing in each direction, relying on their inherent instincts, yet there are a few snakes that build a nest for the youngsters and protect it until time comes for them to go out.
Nutrition
Snakes are carnivorous; they feed on a variety of sources of preys and their small ones feed on insects, while large snakes eat preys available in their environment such as mice, rabbits and small birds, while huge snakes feed on some large animals such as pigs and capybara, snakes swallow their preys wholly and the absence of gums or teeth facilitates swallowing preys as a whole, chewing on them, snakes break their preys after swallowing them with abdominal muscles that act as a substitute for the teeth, being ectothermic (“cold-blooded”). Food digestion in snakes is slow and they eat at intervals, for example, anaconda, which lives in South America, eats on average every six months, and some snakes specialize in eating bird eggs, swallowing the egg and using its vertebrae to break it down, and then vomiting the rest of the crusts, while other snakes were found to consume small crocodiles.
Snake bite
Most species of snake are nonvenomous and those that have venom (400 species) use it primarily to kill and subdue preys rather than for self-defense in two manners:
Either its prey is bitten by its poisonous fangs, which are used to inject preys with venom, each with a small hole, and when applied to the prey, these fangs act like a medical needle, injecting a toxic substance into the prey’s blood.
Or other toxic species, with axis fangs that apply to the inside when the snake’s mouth is closed, and when it opens its mouth, these fangs are stagged.
Snakes with fixed toxic fangs do not sting but bite, especially those that have toxic fangs that are not in the form of medical needles but whose posterior fangs have longitudinal cracks through which venom passes to the prey’s blood; they need to handicap the prey for a while, in order to ensure that poison passes into the victim’s body, so such snakes are considered semi-toxic and are not dangerous to humans in general as man can get rid of their toxic fangs quickly.
Snake venoms are complex mixtures of proteins and minerals; Snake venom is derived from the poison glands in the snake’s head and is tied to fangs, which paralyzes the victim or prey, and is also the first step of digestion of the snake as the poison causes shock to the victim and begins to penetrate through lymphatic devices and destroy blood cells and vital organs, especially kidneys, and there are snakes whose toxins affect the nervous system or blood circulation or causes severe damages to lungs, thus leading to a rapid death of snake preys due to asphyxiation, internal bleeding and other damage caused by these toxins.
There are snakes, which use toxins without direct contact with victims, such as bites and stings, a good example of which is the cobra snake that can squirt poison into the eyes of its prey, causing blindness, and it does so by a shrinking muscle that wraps around the poison glands; if the snake wants to squirt its poison, this muscle contracts quickly and strongly makes the poison rush through the holes of the fangs for several meters away.