Amazing snakes

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 Snakes are elongate, legless, carnivorous reptiles of the suborder Serpentes that can be distinguished from legless lizards by their lack of eyelids and external ears. Like all squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales. Many species of snakes have skulls with many more joints than their lizard ancestors, enabling them to swallow prey much larger than their heads with their highly mobile jaws. To accommodate their narrow bodies, snakes' paired organs (such as kidneys) appear one in front of the other instead of side by side, and most have only one functional lung. Some species retain a pelvic girdle with a pair of vestigial claws on either side of the cloaca.

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Living snakes are found on every continent except Antarctica and on most islands. Fifteen families are currently recognized, comprising 456 genera and over 2,900 species.They range in size from the tiny, 10 cm-long thread snake to pythons and anacondas of up to 7.6 metres (25 ft) in length. The recently discovered fossil Titanoboa was 15 metres (49 ft) long. Snakes are thought to have evolved from either burrowing or aquatic lizards during the Cretaceous period (c 150 Ma). The diversity of modern snakes appeared during the Paleocene period (c 66 to 56 Ma).



Most species are nonvenomous and those that have venom use it primarily to kill and subdue prey rather than for self-defense. Some possess venom potent enough to cause painful injury or death to humans. Nonvenomous snakes either swallow prey alive or kill by constriction.

VENOM

Cobras, vipers, and closely related species use venom to immobilize or kill their prey. The venom is modified saliva, delivered through fangs.The fangs of 'advanced' venomous snakes like viperids and elapids are hollow to inject venom more effectively, while the fangs of rear-fanged snakes such as the boomslang merely have a groove on the posterior edge to channel venom into the wound. Snake venoms are often prey specific, their role in self-defense is secondary.Venom, like all salivary secretions, is a predigestant that initiates the
breakdown of food into soluble compounds, facilitating proper digestion. Even nonvenomous snake bites (like any animal bite) will cause tissue damage.

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Certain birds, mammals, and other snakes such as kingsnakes that prey on venomous snakes have developed resistance and even immunity to certain venoms.Venomous snakes include three families of snakes, and do not constitute a formal classification group used in taxonomy. The term poisonous snake is mostly incorrect; poison is inhaled or ingested, whereas venom is injected.There are, however, two exceptions—Rhabdophis sequesters toxins from the toads it eats, then secretes them from nuchal glands to ward off predators, and a small population of garter snakes in Oregon retains enough toxin in their liver from the newts they eat to be effectively poisonous to local small predators such as crows and foxes.

Snake venoms are complex mixtures of proteins, and are stored in poison glands at the back of the head.In all venomous snakes, these glands open through ducts into grooved or hollow teeth in the upper jaw.These proteins can potentially be a mix of neurotoxins (which attack the nervous system), hemotoxins (which attack the circulatory system), cytotoxins, bungarotoxins and many other toxins that affect the body in different ways.Almost all snake venom contains hyaluronidase, an enzyme that ensures rapid diffusion of the venom.

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Venomous snakes that use hemotoxins usually have the fangs that secrete the venom in the front of their mouths, making it easier for them to inject the venom into their victims.Some snakes that use neurotoxins, such as the mangrove snake, have their fangs located in the back of their mouths, with the fangs curled backwards.This makes it both difficult for the snake to use its venom and for scientists to milk them.Elapid snakes, however, such as cobras and kraits are proteroglyphous, possessing hollow fangs that cannot be erected toward the front of their mouths and cannot "stab" like a viper; they must actually bite the victim.

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It has recently been suggested that all snakes may be venomous to a certain degree, with harmless snakes having weak venom and no fangs.Most snakes currently labelled “nonvenomous” would still be considered harmless according to this theory, as these snakes either lack a delivery method for the venom or are simply incapable of delivering enough to endanger a human. This theory postulates snakes may have evolved from a common lizard ancestor that was venomous, from which venomous lizards like the gila monster and beaded lizard may also have derived, as well as the monitor lizards and now extinct mosasaurs. They share this venom clade with various other saurian species.

Venomous snakes are classified in two taxonomic families:

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    * Elapids – cobras including king cobras, kraits, mambas, Australian copperheads, sea snakes, and coral snakes.
    * Viperids – vipers, rattlesnakes, copperheads/cottonmouths, adders and bushmasters.

There is a third family containing the opistoglyphous (rear-fanged) snakes as well as the majority of other snake species:

    * Colubrids – boomslangs, tree snakes, vine snakes, mangrove snakes, although not all colubrids are venomous.

 RELIGION

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A snake associated with Saint Simeon Stylites.
 Snakes are a part of Hindu worship. A festival Nag Panchami is celebrated every year on snakes. Most images of Lord Shiva depict snake around his neck. Puranas have various stories associated with Snakes. In the Puranas, Shesha is said to hold all the planets of the Universe on his hoods and to constantly sing the glories of Vishnu from all his mouths. He is sometimes referred to as "Ananta-Shesha," which means "Endless Shesha." Other notable snakes in Hinduism are Ananta, Vasuki, Taxak, Karkotaka and Pingala. The term Naga is used to refer to entities that take the form of large snakes in Hinduism and Buddhism.
Rod of Asclepius, in which the snakes, through ecdysis, symbolize healing.

Snakes have also been widely revered, such as in ancient Greece, where the serpent was seen as a healer, and Asclepius carried two intertwined on his wand, a symbol seen today on many ambulances.

In Judaism, the snake of brass is also a symbol of healing, of one's life being saved from imminent death.
Lilith with a snake, (1892), by John Collier (1892).

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In Christianity, Christ's redemptive work is compared to saving one's life through beholding the Nehushtan (serpent of brass) (Gospel of John 3:14). Snake handlers use snakes as an integral part of church worship in order to exhibit their faith in divine protection. However, more commonly in Christianity, the serpent has been seen as a representative of evil and sly plotting, which can be seen in the description in Genesis chapter 3 of a snake in the Garden of Eden tempting Eve. Saint Patrick is reputed to have expelled all snakes from Ireland while Christianising the country in the 5th century, thus explaining the absence of snakes there.

In Christianity and Judaism, the snake makes its infamous appearance in the first book (Genesis 3:1) of the Bible when a serpent appears before the first couple Adam and Eve and tempts them with the forbidden fruit from the Tree of Knowledge. The snake returns in Exodus when Moses, as a sign of God's power, turns his staff into a snake and when Moses made the Nehushtan, a bronze snake on a pole that when looked at cured the people of bites from the snakes that plagued them in the desert. The serpent makes its final appearance symbolizing Satan in the Book of Revelation: "And he laid hold on the dragon the old serpent, which is the devil and Satan, and bound him for a thousand years.




In Neo-Paganism and Wicca, the snake is seen as a symbol of wisdom and knowledge.