Minoan Snake Goddess

Women in the Aegean Minoan Snake Goddess Christopher L. C. E. Witcombe

8. Snakes, Egypt, Magic & Women Following his discussion of the snake as a household deity, Evans comments on the similarity in Minoan Snake Goddess from Knossos, Crete the position of the snake raising its head above the hat of the principal "Snake Goddess" (Evans here ignoring the fact that this particular detail of the figurine is his own reconstruction - see Evans's "Snake Goddess") and that of the Egyptian uraeus (rearing cobra snake) on the head of Hathor and other Egyptian goddesses. In particular, Evans tentatively links the "Snake Goddess" with the Egyptian Goddess Wazet (i.e. Wadjyt), the snake goddess of the Nile Delta, but does not pursue the connection. It is clear that the Minoans borrowed much their culture and various cult practices from Egypt. Numerous Egyptian objects of one kind or another were found by Evans at Knossos. The most spectacular discovery was the lower part of diorite statue of a seated Egyptian figure identified from the hieroglyphic inscriptions as a priest of Wadjyt (or Wadjet; written as Wazet by Evans; and as Uatchet, or Uatchit, by Budge [see Budge in the BIBLIOGRAPHY]). As was noted above, sacred to Wadjyt was the cobra snake which in the form of the uraeus became the distinctive emblem of the Kingdom of Lower Egypt and the Egyptian royal house. Wadjyt was principally the snake goddess of Buto, or Pe, her ancient sanctuary in the Nile Delta. She was also associated with the city known to the Greeks as Aphroditopolis (the city of Aphrodite; the signs of the nome of Aphroditopolis were a snake and a feather), with whom Wadjyt was identified. Like Aphrodite, Wadjyt was a goddess of fertility. Later, she was assimilated with Isis. In her snake form, Wadjyt is sometimes identified as Weret-hekau, "Great of Magic", who, as the uraeus, a manifestation of the solar eye, rises from the forehead of Horus (the pharaoh). As the uraeus, Wadjyt and Weret-hekau were identified with the eye of Re. The Goddesses Tefnut and Bastet were also identified with the eye of Re. As both were commonly shown lioness-headed, so Wadjyt and Weret-hekau were also sometimes represented with lioness-heads. This has sometimes caused all these goddesses to be identified with the lioness goddess Sekhmet. Originally simply an epithet applied to goddesses, crowns, and uraeus, Weret-hekau was also a goddess in her own right. Her principal tasks were to protect the creator sun god and to act as foster-mother to the pharaohs. Weret-hekau's name, together with snake decoration and solar eyes, occasionally appears on magical implements such as model throwsticks (used by the deceased to defend themselves against malevolent spirits and demons), and apotropaic wands (or 'magic knives') made of ivory which seem to have been used to protect women, especially pregnant or nursing women, and women with children. Among the papyri found in a cache of magical objects in a tomb under the Ramesseum (see below) is one devoted to spells for women and children. Magic was a beneficial force in Egypt and was used widely in all periods. The earliest attested magical texts are in the Pyramid Texts composed late in Dynasty V and Dynasty VI in the Old Kingdom. The god of magic, Heka (heka is also the Egyptian word for 'magic'), to whom shrines were dedicated in Lower Egypt, was depicted in human form (sometimes with a snake head) holding a snake-shaped wand in each hand. The snake wand, which was also used by magicians, probably represented Weret-hekau. Wooden statuette of a woman holding metal snakes Dynasty XIII (1786-1633 BCE) (The Manchester Museum, University of Manchester, England) The combination of snake wands and the lioness head is seen in a wooden statuette of woman with movable arms found in 1896 by James Edward Quibell in a cache of magical objects in a tomb dating to Dynasty XIII (1786-1633 BCE) discovered under the Ramesseum, the mortuary temple of Ramesses II (1290-1224 BCE), at Thebes. The statuette, which holds a metal snake-wand in each hand, is thought to represent a female sau, a type of magician, who could supply magical protection (the Egyptian verb sa means "to protect") both by making charms and amulets, and by using spoken and written charms. Besides the statuette, the cache also included some magico-medical papyri and a twisting bronze snake wand (now in the Fitzwilliam Museum, Cambridge) which was evidently intended to be held in the middle where its body flattens out. It is approximately twice the size of those held by the wooden figurine. Possibly the Minoan votary is also holding snake-wands. The sau statuette is usually described as representing either the beneficent lion-demon later known as Bes (a god often called upon to protect women in childbirth and their infants), or a woman playing the role of the demon in a magical rite. However, the combination of lioness mask and snakes also suggests that she might be representing or serving in some way, perhaps as a votary or a priestess, the goddess Wadjyt. Her nudity may indicate a connection with fertility figurines (a group of which were found in the same cache), or that she is a religious dancer who helped in the protective rites. An interesting feature of the Egyptian statuette is its moveable arms which could be raised so that the metal snakes in each hand are held up in a manner reminiscent of the Minoan Snake Goddess.

Rom Whitaker,

Rom Whitaker, popularly known as the snake man of India, has been working with reptiles here since the 1960s Please use the links on the left to browse the projects that Rom is involved in. Rom with a cobra rescued from a farmer’s house at Agumbe. . His conservationist career began with the campaign for the preservation of Silent Valley (which became an icon of the conservation movement in India). He was then instrumental in banning the exploitative snake skin industry and set up a tribal cooperative for Irula tribal snake hunters. India's first reptile park, the Madras Snake Park and India's crocodile gene bank, the Madra For more than a decade, Janaki Lenin’s identity was that of a film-maker. She was trained to be an editor at the Film and Television Institute of Tamil Nadu, South India. After six weary years of editing advertising commercials and soap operas, she was looking for a change of direction. Getting involved with Romulus Whitaker opened up new avenues in wildlife film-making. Together they founded Draco Films and produced more than a dozen films for National Geographic Television. Janaki with members of the team at Namdapha National Park, one of the remotest spots in India. A decade later, Janaki finds herself forging a new identity as a book publisher and writer. Her focus, as publisher, is mainly on producing world-class field guides to the fauna of India and making them available in 15 Indian languages at subsidized prices. She has written on a wide range of wildlife and conservation subjects for national newspapers, wildlife and travel magazines. She facilitates a working group of primatologists which drafted a national Action Plan for nuisance primates. She is also drafting an action plan for the mitigation of human-elephant conflict in India in collaboration with Asian Nature Conservation Foundation, Bangalore. Janaki is currently working to enlarge the scope of this initiative to include other animals caught in conflict situations with humans. s Crocodile Bank were also started by him. Rom has traveled to several developing countries like Bangladesh, Mozambique, Papua New Guinea, Malaysia and Indonesia as a wildlife management consultant for the United Nations. He has written books, scientific papers and popular articles, and produced and presented movies. He lives with his life partner, Janaki Lenin, on a farm south of the city of Chennai, India. He has established field stations in the Andaman Islands and the Western Ghats to foster research. The various organizations he set up - the Madras Snake Park, Madras Crocodile Bank and Agumbe Rainforest Research Station - have functioned as resources for conservation education.

A former filmmaker, Janaki Lenin, currently tries to make a living publishing books while spending more time doing what she loves best - writing. Although she helped Rom in his conservation efforts for more than a decade, she was not an active conservationist until she stumbled on human-wildlife conflict mitigation. She thinks she has finally found the hook she needed to enter the field! She is currently the Regional Chair of the IUCN/SSC Crocodile Specialist Group for South Asia and Iran.

Symbolism

Symbolism

Main article: Serpent (symbolism)

In Egyptian history, the snake occupies a primary role with the Nile cobra adorning the crown of the pharaoh in ancient times. It was worshipped as one of the gods and was also used for sinister purposes: murder of an adversary and ritual suicide (Cleopatra).

Medusa by 16th Century Italian artist Caravaggio.

In Greek mythology snakes are often associated with deadly and dangerous antagonists, but this is not to say that snakes are symbolic of evil; in fact, snakes are a chthonic symbol, roughly translated as 'earthbound'. The nine-headed Lernaean Hydra that Hercules defeated and the three Gorgon sisters are children of Gaia, the earth.^[72] Medusa was one of the three Gorgon sisters who Perseus defeated.^[72] Medusa is described as a hideous mortal, with snakes instead of hair and the power to turn men to stone with her gaze.^[72] After killing her, Perseus gave her head to Athena who fixed it to her shield called the Aegis.^[72] The Titans are also depicted in art with snakes instead of legs and feet for the same reason—they are children of Gaia and Ouranos (Uranus), so they are bound to the earth.
Three medical symbols involving snakes that are still used today are Bowl of Hygieia, symbolizing pharmacy, and the Caduceus and Rod of Asclepius, which are symbols denoting medicine in general.^[32]
India is often called the land of snakes and is steeped in tradition regarding snakes.^[73] Snakes are worshipped as gods even today with many women pouring milk on snake pits (despite snakes' aversion for milk).^[73] The cobra is seen on the neck of Shiva and Vishnu is depicted often as sleeping on a seven-headed snake or within the coils of a serpent.^[74] There are also several temples in India solely for cobras sometimes called Nagraj (King of Snakes) and it is believed that snakes are symbols of fertility. There is a Hindu festival called Nag Panchami each year on which day snakes are venerated and prayed to. See also Nāga.
In India there is another mythology about snakes. Commonly known in Hindi as "Ichchhadhari" snakes. Such snakes can take the form of any living creature, but prefer human form. These mythical snakes possess a valuable gem called "Mani", which is more brilliant than diamond. There are many stories in India about greedy people trying to possess this gem and ending up getting killed.
The Ouroboros is a symbol associated with many different religions and customs, and is claimed to be related to Alchemy. The Ouroboros or Oroboros is a snake eating its own tail in a clock-wise direction (from the head to the tail) in the shape of a circle, representing manifestation of one's own life and rebirth, leading to immortality.
The snake is one of the 12 celestial animals of Chinese Zodiac, in the Chinese calendar.
Many ancient Peruvian cultures worshipped nature.^[75] They emphasized animals and often depicted snakes in their art.^[76]

Religion

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 Nāga 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 (Book of Numbers 26:6–9).

Lilith with a snake, (1892), by John Collier (1892).

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." (Revelation 20:2)
In Neo-Paganism and Wicca, the snake is seen as a symbol of wisdom and knowledge.

Place names

Various locations in different countries are called for snakes, such as the Snake River in the United States and Snake

Consumption

A "海豹蛇" ("sea-leopard snake," supposedly Enhydris bocourti) occupies a place of honor among the live delicacies waiting to meet their consumers outside of a Guangzhou restaurant.

Snake Meat, in a Taipei restaurant

While not commonly thought of as food in most cultures, in some cultures, the consumption of snakes is acceptable, or even considered a delicacy, prized for its alleged pharmaceutical effect of warming the heart. Snake soup of Cantonese cuisine is consumed by local people in autumn, to warm up their body. Western cultures document the consumption of snakes under extreme circumstances of hunger.^[67] Cooked rattlesnake meat is an exception, which is commonly consumed in parts of the Midwestern United States. In Asian countries such as China, Taiwan, Thailand, Indonesia, Vietnam and Cambodia, drinking the blood of snakes—particularly the cobra—is believed to increase sexual virility.^[68] The blood is drained while the cobra is still alive when possible, and is usually mixed with some form of liquor to improve the taste.^[68]
In some Asian countries, the use of snakes in alcohol is also accepted. In such cases, the body of a snake or several snakes is left to steep in a jar or container of liquor. It is claimed that this makes the liquor stronger (as well as more expensive). One example of this is the Habu snake sometimes placed in the Okinawan liquor Awamori also known as "Habu Sake."^[69]
U.S. Army Special Forces trainees are taught to catch, kill, and eat snakes during their survival course; this has earned them the nickname "snake eaters," which the video game Metal Gear Solid 3: Snake Eater may be implied to draw off of.
Snake wine (蛇酒) is an alcoholic beverage produced by infusing whole snakes in rice wine or grain alcohol. The drink was first recorded to have been consumed in China during the Western Zhou dynasty and considered an important curative and believed to reinvigorate a person according to Traditional Chinese medicine.^[70]
Island (Black Sea) (derived from "Fidonisi," which means the same in Greek).

Reproduction

Terrestrial

Terrestrial lateral undulation is the most common mode of terrestrial locomotion for most snake species.^[44] In this mode, the posteriorly moving waves push against contact points in the environment, such as rocks, twigs, irregularities in the soil, etc.^[44] Each of these environmental objects, in turn, generates a reaction force directed forward and towards the midline of the snake, resulting in forward thrust while the lateral components cancel out.^[48] The speed of this movement depends upon the density of push-points in the environment, with a medium density of about 8 along the snake's length being ideal.^[46] The wave speed is precisely the same as the snake speed, and as a result, every point on the snake's body follows the path of the point ahead of it, allowing snakes to move through very dense vegetation and small openings.^[48]

Aquatic

Main article: Sea snake

Banded sea krait, Laticauda sp.

When swimming, the waves become larger as they move down the snake's body, and the wave travels backwards faster than the snake moves forwards.^[49] Thrust is generated by pushing their body against the water, resulting in the observed slip. In spite of overall similarities, studies show that the pattern of muscle activation is different in aquatic versus terrestrial lateral undulation, which justifies calling them separate modes.^[50] All snakes can laterally undulate forward (with backward-moving waves), but only sea snakes have been observed reversing the motion (moving backwards with forward-moving waves).^[44]

Sidewinding

See also: Sidewinding

A Mojave rattlesnake (Crotalus scutulatus) sidewinding.

Most often employed by colubroid snakes (colubrids, elapids, and vipers) when the snake must move in an environment that lacks irregularities to push against (rendering lateral undulation impossible), such as a slick mud flat, or a sand dune. Sidewinding is a modified form of lateral undulation in which all of the body segments oriented in one direction remain in contact with the ground, while the other segments are lifted up, resulting in a peculiar "rolling" motion.^[51][52] This mode of locomotion overcomes the slippery nature of sand or mud by pushing off with only static portions on the body, thereby minimizing slipping.^[51] The static nature of the contact points can be shown from the tracks of a sidewinding snake, which show each belly scale imprint, without any smearing. This mode of locomotion has very low caloric cost, less than ⅓ of the cost for a lizard or snake to move the same distance.^[47] Contrary to popular belief, there is no evidence that sidewinding is associated with the sand being hot.^[51]

Concertina

Main article: Concertina movement

When push-points are absent, but there is not enough space to use sidewinding because of lateral constraints, such as in tunnels, snakes rely on concertina locomotion.^[44][52] In this mode, the snake braces the posterior portion of its body against the tunnel wall while the front of the snake extends and straightens.^[51] The front portion then flexes and forms an anchor point, and the posterior is straightened and pulled forwards. This mode of locomotion is slow and very demanding, up to seven times the cost of laterally undulating over the same distance.^[47] This high cost is due to the repeated stops and starts of portions of the body as well as the necessity of using active muscular effort to brace against the tunnel walls.

Rectilinear

Main article: Rectilinear locomotion

The slowest mode of snake locomotion is rectilinear locomotion, which is also the only one where the snake does not need to bend its body laterally, though it may do so when turning.^[53] In this mode, the belly scales are lifted and pulled forward before being placed down and the body pulled over them. Waves of movement and stasis pass posteriorly, resulting in a series of ripples in the skin.^[53] The ribs of the snake do not move in this mode of locomotion and this method is most often used by large pythons, boas, and vipers when stalking prey across open ground as the snake's movements are subtle and harder to detect by their prey in this manner.^[51]

Other

The movement of snakes in arboreal habitats has only recently been studied.^[54] While on tree branches, snakes use several modes of locomotion depending on species and bark texture.^[54] In general, snakes will use a modified form of concertina locomotion on smooth branches, but will laterally undulate if contact points are available.^[54] Snakes move faster on small branches and when contact points are present, in contrast to limbed animals, which do better on large branches with little 'clutter'.^[54]
Gliding snakes (Chrysopelea) of Southeast Asia launch themselves from branch tips, spreading their ribs and laterally undulating as they glide between trees.^[51][55][56] These snakes can perform a controlled glide for hundreds of feet depending upon launch altitude and can even turn in midair.^[51][55]

Reproduction

Although a wide range of reproductive modes are used by snakes, all snakes employ internal fertilization. This is accomplished by means of paired, forked hemipenes, which are stored, inverted, in the male's tail.^[57] The hemipenes are often grooved, hooked, or spined in order to grip the walls of the female's cloaca.^[57]
Most species of snakes lay eggs, but most snakes abandon the eggs shortly after laying. However, a few species (such as the King cobra) actually construct nests and stay in the vicinity of the hatchlings after incubation.^[57] Most pythons coil around their egg-clutches and remain with them until they hatch.^[58] A female python will not leave the eggs, except to occasionally bask in the sun or drink water. She will even “shiver” to generate heat to incubate the eggs.^[58]
Some species of snake are ovoviviparous and retain the eggs within their bodies until they are almost ready to hatch.^[59][60] Recently, it has been confirmed that several species of snake are fully viviparous, such as the boa constrictor and green anaconda, nourishing their young through a placenta as well as a yolk sac, which is highly unusual among reptiles, or anything else outside of placental mammals.^[59][60] Retention of eggs and live birth are most often associated with colder environments, as the retention of the young within the female.^[57][60]

Interactions with humans

Most common symptoms of any kind of snake bite poisoning.^[61][62][63] Furthermore, there is vast variation in symptoms between bites from different types of snakes.^[61]

Bite

Main article: Snakebite

Vipera berus, one fang in glove with a small venom stain, the other still in place.

Snakes do not ordinarily prey on humans, and most will not attack humans unless the snake is startled or injured, preferring instead to avoid contact. With the exception of large constrictors, nonvenomous snakes are not a threat to humans. The bite of nonvenomous snakes is usually harmless because their teeth are designed for grabbing and holding, rather than tearing or inflicting a deep puncture wound. Although the possibility of an infection and tissue damage is present in the bite of a nonvenomous snake, venomous snakes present far greater hazard to humans.^[7]:209
Documented deaths resulting from snake bites are uncommon. Nonfatal bites from venomous snakes may result in the need for amputation of a limb or part thereof. Of the roughly 725 species of venomous snakes worldwide, only 250 are able to kill a human with one bite. Australia averages only one fatal snake bite per year. In India, 250,000 snakebites are recorded in a single year, with as many as 50,000 recorded initial deaths.^[64]
The treatment for a snakebite is as variable as the bite itself. The most common and effective method is through antivenom (or antivenin), a serum made from the venom of the snake. Some antivenom is species specific (monovalent) while some is made for use with multiple species in mind (polyvalent). In the United States for example, all species of venomous snakes are pit vipers, with the exception of the coral snake. To produce antivenom, a mixture of the venoms of the different species of rattlesnakes, copperheads, and cottonmouths is injected into the body of a horse in ever-increasing dosages until the horse is immunized. Blood is then extracted from the immunized horse; the serum is separated and further purified and freeze-dried. It is reconstituted with sterile water and becomes antivenom. For this reason, people who are allergic to horses cannot be treated using antivenom. Antivenom for the more dangerous species (such as mambas, taipans, and cobras) is made in a similar manner in India, South Africa, and Australia, although these antivenoms are species-specific.

Snake charmers

Main article: Snake charming

An Indian cobra in a basket with a snake charmer. These snakes are perhaps the most common subjects of snake charmings.

In some parts of the world, especially in India, snake charming is a roadside show performed by a charmer. In such a show, the snake charmer carries a basket that contains a snake that he seemingly charms by playing tunes from his flutelike musical instrument, to which the snake responds.^[65] Snakes lack external ears, though they do have internal ears, and respond to the movement of the flute, not the actual noise.^[65]
The Wildlife Protection Act of 1972 in India technically proscribes snake charming on grounds of reducing animal cruelty. Other snake charmers also have a snake and mongoose show, where both the animals have a mock fight; however, this is not very common, as the snakes, as well as the mongooses, may be seriously injured or killed. Snake charming as a profession is dying out in India because of competition from modern forms of entertainment and environment laws proscribing the practice.^[65]

Trapping

The Irulas tribe of Andhra Pradesh and Tamil Nadu in India have been hunter-gatherers in the hot, dry plains forests, and have practiced the art of snake catching for generations. They have a vast knowledge of snakes in the field. They generally catch the snakes with the help of a simple stick. Earlier, the Irulas caught thousands of snakes for the snake-skin industry. After the complete ban on snake-skin industry in India and protection of all snakes under the Indian Wildlife (Protection) Act 1972, they formed the Irula Snake Catcher's Cooperative and switched to catching snakes for removal of venom, releasing them in the wild after four extractions. The venom so collected is used for producing life-saving antivenom, biomedical research and for other medicinal products.^[66] The Irulas are also known to eat some of the snakes they catch and are very useful in rat extermination in the villages.
Despite the existence of snake charmers, there have also been professional snake catchers or wranglers. Modern-day snake trapping involves a herpetologist using a long stick with a V- shaped end. Some television show hosts, like Bill Haast, Austin Stevens, Steve Irwin, and Jeff Corwin, prefer to catch them using bare hands.

Consumption

Perception

Perception

Eyesight

Snake vision varies greatly, from only being able to distinguish light from dark to keen eyesight, but the main trend is that their vision is adequate although not sharp, and allows them to track movements.^[33] Generally, vision is best in arboreal snakes and weakest in burrowing snakes. Some snakes, such as the Asian vine snake (genus Ahaetulla), have binocular vision, with both eyes capable of focusing on the same point. Most snakes focus by moving the lens back and forth in relation to the retina, while in the other amniote groups, the lens is stretched.

Smell

Snakes use smell to track their prey. They smell by using their forked tongues to collect airborne particles, then passing them to the vomeronasal organ orJacobson's organ in the mouth for examination.^[34] The fork in the tongue gives snakes a sort of directional sense of smell and taste simultaneously.^[34] They keep their tongues constantly in motion, sampling particles from the air, ground, and water, analyzing the chemicals found, and determining the presence of prey or predators in the local environment.^[34]

Thermographic image of a snake eating a mouse

Vibration sensitivity

The part of the body in direct contact with the ground is very sensitive to vibration; thus, a snake can sense other animals approaching by detecting faint vibrations in the air and on the ground.^[34]

Infrared sensitivity

Pit vipers, pythons, and some boas have infrared-sensitive receptors in deep grooves between the nostril and eye, although some have labial pits on their upper lip just below the nostrils (common in pythons), which allow them to "see" the radiated heat of warm-blooded prey mammals.^[34]

Venom

See also: Snake venom

Milk snakes are often mistaken for coral snakes, whose venom is deadly to humans.

Cobras, vipers, and closely related species use venom to immobilize or kill their prey. The venom is modified saliva, delivered through fangs.^[7]:243 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.^[7]:243 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.^[7]:209
Certain birds, mammals, and other snakes such as kingsnakes that prey on venomous snakes have developed resistance and even immunity to certain venoms.^[7]:243 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.^[35] 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.^[36]
Snake venoms are complex mixtures of proteins, and are stored in poison glands at the back of the head.^[36] In all venomous snakes, these glands open through ducts into grooved or hollow teeth in the upper jaw.^[7]:243[35] 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.^[35] Almost all snake venom contains hyaluronidase, an enzyme that ensures rapid diffusion of the venom.^[7]:243
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.^[35] 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.^[37] This makes it both difficult for the snake to use its venom and for scientists to milk them.^[35] 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.^[7]:242
It has recently been suggested that all snakes may be venomous to a certain degree, with harmless snakes having weak venom and no fangs.^[38] 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:

• Elapids – cobras including king cobras, kraits, mambas, Australian copperheads, sea snakes, and coral snakes.^[37]
• Viperids – vipers, rattlesnakes, copperheads/cottonmouths, adders and bushmasters.^[37]

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.^[7]:209[37]

Behavior

Feeding and diet

Snake eating a rodent.

Carpet python constricting and consuming a chicken.

All snakes are strictly carnivorous, eating small animals including lizards, other snakes, small mammals, birds, eggs, fish, snails or insects.^{[7][1][8][39]} Because snakes cannot bite or tear their food to pieces, they must swallow prey whole. The body size of a snake has a major influence on its eating habits. Smaller snakes eat smaller prey. Juvenile pythons might start out feeding on lizards or mice and graduate to small deer or antelope as an adult, for example.

African egg-eating snake.

The snake's jaw is a complex structure. Contrary to the popular belief that snakes can dislocate their jaws, snakes have a very flexible lower jaw, the two halves of which are not rigidly attached, and numerous other joints in their skull (see snake skull), allowing them to open their mouths wide enough to swallow their prey whole, even if it is larger in diameter than the snake itself,^[39] as snakes do not chew. For example, the African egg-eating snake has flexible jaws adapted for eating eggs much larger than the diameter of its head.^[7]:81 This snake has no teeth, but does have bony protrusions on the inside edge of its spine, which it uses to break shells when it eats eggs.^[7]:81
While the majority of snakes eat a variety of prey animals, there is some specialization by some species. King cobras and the Australian bandy-bandy consume other snakes. Pareas iwesakii and other snail-eating colubrids of subfamily Pareatinae have more teeth on the right side of their mouths than on the left, as the shells of their prey usually spiral clockwise^[7]:184[40]
Some snakes have a venomous bite, which they use to kill their prey before eating it.^[39][41] Other snakes kill their prey by constriction.^[39] Still others swallow their prey whole and alive.^[7]:81[39]
After eating, snakes become dormant while the process of digestion takes place.^[42] Digestion is an intense activity, especially after consumption of large prey. In species that feed only sporadically, the entire intestine enters a reduced state between meals to conserve energy. The digestive system is then 'up-regulated' to full capacity within 48 hours of prey consumption. Being ectothermic (“cold-blooded”), the surrounding temperature plays a large role in snake digestion. The ideal temperature for snakes to digest is 30 °C (86 °F). So much metabolic energy is involved in a snake's digestion that in the Mexican rattlesnake (Crotalus durissus), surface body temperature increases by as much as 1.2 °C (2.2 °F) during the digestive process.^[43] Because of this, a snake disturbed after having eaten recently will often regurgitate its prey to be able to escape the perceived threat. When undisturbed, the digestive process is highly efficient, with the snake's digestive enzymes dissolving and absorbing everything but the prey's hair (or feathers) and claws, which are excreted along with waste.

Locomotion

The lack of limbs does not impede the movement of snakes. They have developed several different modes of locomotion to deal with particular environments. Unlike the gaits of limbed animals, which form a continuum, each mode of snake locomotion is discrete and distinct from the others; transitions between modes are abrupt.^[44][45]

Lateral undulation

Main article: Undulatory locomotion

Lateral undulation is the sole mode of aquatic locomotion, and the most common mode of terrestrial locomotion.^[45] In this mode, the body of the snake alternately flexes to the left and right, resulting in a series of rearward-moving "waves."^[44] While this movement appears rapid, snakes have rarely been documented moving faster than two body-lengths per second, often much less.^[46] This mode of movement has the same net cost of transport (calories burned per meter moved) as running in lizards of the same mass.^[47]

Biology

When compared, the skeletons of snakes are radically different from those of most other reptiles (such as the turtle, right), being made up almost entirely of an extended ribcage.

Skeleton

The skeleton of most snakes consists solely of the skull, hyoid, vertebral column, and ribs, though henophidian snakes retain vestiges of the pelvis and rear limbs. The skull of the snake consists of a solid and complete braincase, to which many of the other bones are only loosely attached, particularly the highly mobile jaw bones, which facilitate manipulation and ingestion of large prey items. The left and right sides of the lower jaw are joined only by a flexible ligament at the anterior tips, allowing them to separate widely, while the posterior end of the lower jaw bones articulate with a quadrate bone, allowing further mobility. The bones of the mandible and quadrate bones can also pick up ground borne vibrations.^[20] The hyoid is a small bone located posterior and ventral to the skull, in the 'neck' region, which serves as an attachment for muscles of the snake's tongue, as it does in all other tetrapods.
The vertebral column consists of anywhere between 200–400 (or more) vertebrae. Tail vertebrae are comparatively few in number (often less than 20% of the total) and lack ribs, while body vertebrae each have two ribs articulating with them. The vertebrae have projections that allow for strong muscle attachment enabling locomotion without limbs. Autotomy of the tail, a feature found in some lizards is absent in most snakes.^[21] Caudal autotomy in snakes is rare and is intervertebral, unlike that in lizards, which is intravertebral—that is, the break happens along a predefined fracture plane present on a vertebra.^[22][23]
In some snakes, most notably boas and pythons, there are vestiges of the hindlimbs in the form of a pair of pelvic spurs. These small, claw-like protrusions on each side of the cloaca are the external portion of the vestigial hindlimb skeleton, which includes the remains of an ilium and femur.

Internal organs

Anatomy of a snake. 1 esophagus, 2 trachea, 3 tracheal lungs, 4 rudimentary left lung, 5 right lung, 6 heart, 7 liver, 8 stomach, 9 air sac, 10 gallbladder, 11 pancreas, 12 spleen, 13 intestine, 14 testicles, 15 kidneys.

The snake's heart is encased in a sac, called the pericardium, located at the bifurcation of the bronchi. The heart is able to move around, however, owing to the lack of a diaphragm. This adjustment protects the heart from potential damage when large ingested prey is passed through the esophagus. The spleen is attached to the gall bladder and pancreas and filters the blood. The thymus gland is located in fatty tissue above the heart and is responsible for the generation of immune cells in the blood. The cardiovascular system of snakes is also unique for the presence of a renal portal system in which the blood from the snake's tail passes through the kidneys before returning to the heart.^[24]
The vestigial left lung is often small or sometimes even absent, as snakes' tubular bodies require all of their organs to be long and thin.^[24] In the majority of species, only one lung is functional. This lung contains a vascularized anterior portion and a posterior portion that does not function in gas exchange.^[24] This 'saccular lung' is used for hydrostatic purposes to adjust buoyancy in some aquatic snakes and its function remains unknown in terrestrial species.^[24] Many organs that are paired, such as kidneys or reproductive organs, are staggered within the body, with one located ahead of the other.^[24] Snakes have no lymph nodes.^[24]

An adult Barbados threadsnake, Leptotyphlops carlae, on an American quarter dollar.

Size

The now extinct Titanoboa cerrejonensis snakes found were 12–15 meters (39–49 ft) in length. By comparison, the largest extant snakes are the reticulated python, which measures about 9 meters (30 ft) long, and the anaconda, which measures about 7.5 meters (25 ft) long^[25] and is considered the heaviest snake on Earth. At the other end of the scale, the smallest extant snake is Leptotyphlops carlae, with a length of about 10 centimeters (4 in).^[26] Most snakes are fairly small animals, approximately 3 feet in length.^[27]

A line diagram from G.A. Boulenger's Fauna of British India (1890) illustrating the terminology of shields on the head of a snake.

Skin

Main article: Snake scales

The skin of a snake is covered in scales. Contrary to the popular notion of snakes being slimy because of possible confusion of snakes with worms, snakeskin has a smooth, dry texture. Most snakes use specialized belly scales to travel, gripping surfaces. The body scales may be smooth, keeled, or granular. The eyelids of a snake are transparent "spectacle" scales, which remain permanently closed, also known as brille.
The shedding of scales is called ecdysis (or in normal usage, moulting or sloughing). In the case of snakes, the complete outer layer of skin is shed in one layer.^[28] Snake scales are not discrete, but extensions of the epidermis—hence they are not shed separately but as a complete outer layer during each moult, akin to a sock being turned inside out.^[29]
The shape and number of scales on the head, back, and belly are often characteristic and used for taxonomic purposes. Scales are named mainly according to their positions on the body. In "advanced" (Caenophidian) snakes, the broad belly scales and rows of dorsal scales correspond to the vertebrae, allowing scientists to count the vertebrae without dissection.

Eye scales visible during the moult of a Diamond Python.

Snakes' eyes are covered by their clear scales (the brille) rather than movable eyelids. Their eyes are always open, and for sleeping, the retina can be closed or the face buried among the folds of the body.

Moulting

Moulting serves a number of functions. Firstly, the old and worn skin is replaced; secondly, it helps get rid of parasites such as mites and ticks. Renewal of the skin by moulting is supposed to allow growth in some animals such as insects; however, this has been disputed in the case of snakes.^[29][30]

A snake shedding its skin.

Moulting occurs periodically throughout a snake's life. Before a moult, the snake stops eating and often hides or moves to a safe place. Just before shedding, the skin becomes dull and dry looking and the eyes become cloudy or blue-colored. The inner surface of the old skin liquefies. This causes the old skin to separate from the new skin beneath it. After a few days, the eyes clear and the snake "crawls" out of its old skin. The old skin breaks near the mouth and the snake wriggles out, aided by rubbing against rough surfaces. In many cases, the cast skin peels backward over the body from head to tail in one piece, like pulling a sock off inside-out. A new, larger, brighter layer of skin has formed underneath.^[29][31]
An older snake may shed its skin only once or twice a year. But a younger snake, still growing, may shed up to four times a year.^[31] The discarded skin gives a perfect imprint of the scale pattern, and it is usually possible to identify the snake if the discarded skin is reasonably intact.^[29] This periodic renewal has led to the snake being a symbol of healing and medicine, as pictured in the Rod of Asclepius.^[32]

Perception