Archived from the original on 30 January Venom, like all salivary secretions, is a predigestant that initiates the breakdown of food into soluble compounds, facilitating proper digestion. Environmental physiology of animals. This established the foundation for the Mesozoic stage, also referred to as the Age of Reptiles. Can't find a vet on my site? Snake soup of Cantonese cuisine is consumed by local people in autumn, to warm up their body. De Wikipedia, la enciclopedia libre.
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. 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". 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.
In the Western world, some snakes especially docile species such as the ball python and corn snake are kept as pets. To meet this demand a captive breeding industry has developed. Snakes bred in captivity tend to make better pets and are considered preferable to wild caught specimens. They require minimal space, as most common species do not exceed 5 feet 1.
Pet snakes can be fed relatively infrequently, usually once every 5 to 14 days. Certain snakes have a lifespan of more than 40 years if given proper care. 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: The ancient Greeks used the Gorgoneion , a depiction of a hideous face with serpents for hair, as an apotropaic symbol to ward off evil.
The legendary account of the foundation of Thebes mentioned a monster snake guarding the spring from which the new settlement was to draw its water. In fighting and killing the snake, the companions of the founder Cadmus all perished — leading to the term " Cadmean victory " i. 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.
India is often called the land of snakes and is steeped in tradition regarding snakes. There is a Hindu festival called Nag Panchami each year on which day snakes are venerated and prayed to. 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 snake is one of the 12 celestial animals of Chinese Zodiac , in the Chinese calendar. Many ancient Peruvian cultures worshipped nature.
Snakes are a part of Hindu worship. 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". Snakes have also been widely revered, such as in ancient Greece , where the serpent was seen as a healer.
Asclepius carried a serpent wound around his wand, a symbol seen today on many ambulances. In religious terms, the snake and jaguar are arguably the most important animals in ancient Mesoamerica. In Judaism , the snake of brass is also a symbol of healing, of one's life being saved from imminent death.
In some parts of Christianity, Christ 's redemptive work is compared to saving one's life through beholding the Nehushtan serpent of brass. 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.
In Christianity and Judaism, the snake makes its infamous appearance in the first book 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 serpent makes its final appearance symbolizing Satan in the Book of Revelation: In Neo-Paganism and Wicca , the snake is seen as a symbol of wisdom and knowledge. Several compounds from snake venoms are being researched as potential treatments or preventatives for pain, cancers, arthritis, stroke, heart disease, hemophilia, and hypertension, and to control bleeding e.
From Wikipedia, the free encyclopedia. This article is about the animal. For other uses, see Snake disambiguation. List of snake genera. Sexual selection in scaled reptiles. Undulatory locomotion and Hydrophiinae. This section needs additional citations for verification. Please help improve this article by adding citations to reliable sources.
Unsourced material may be challenged and removed. April Learn how and when to remove this template message. Snakes of Europe , a wikibook Venomous snake. Revealing the ecology, behavior, and evolutionary history of early snakes using genomics, phenomics, and the fossil record". Integrated Taxonomic Information System. Retrieved 4 April Accessed 4 April Blair Hedges August 4, Archived PDF from the original on August 13, Raffles Bulletin of Zoology.
Archived from the original on David Polly; Carlos A. Archived from the original on 30 January Retrieved 29 January Archived from the original on 17 October Retrieved 12 October Living Snakes of the World in Color. Fossil Snakes of North America First ed. Archived from the original on 26 July Retrieved Jul 24, A Field Guide to Reptiles and Amphibians: Eastern and Central North America.
Auckland , New Zealand: Auckland War Memorial Museum. Are there any snakes in New Zealand?. Archived from the original on 12 July Retrieved 26 April Snake Species of the World: A Taxonomic and Geographic Reference, vol.
Accessed 3 December Archived PDF from the original on Vol I, Loricata and Testudines. A Matter of Scale: Annals of Internal Medicine. Archived from the original on 19 December Australian Biological Resources Studies, Canberra. Journal of Natural History. Russian Journal of Herpetology. Blair; Richardson, Michael K. Sever 19 April Reproductive Biology and Phylogeny of Snakes.
How do a male's morphology and behaviour influence his mating success? Lisle; Weatherhead, Patrick J. Journal of Experimental Biology. The Company of Biologists. Quarterly Journal of Microscopical Science. A Comprehensive Study Guide. Review provided by VeriMed Healthcare Network. Archived from the original on 22 February Retrieved 24 October Archived from the original on 21 August Archived from the original on December 18, British Journal of Herpetology.
Archived from the original on November 17, Archived from the original on November 28, Zug; Molly Dwyer Griffin The Smithsonian Answer Book. Gods, Demons and Symbols of Ancient Mesopotamia: University of Texas Press. The Secret Lore of Egypt: Its Impact on the West.
Ithaca, New York and London, England: Perseus' Battle with the Gorgons. Transactions and Proceedings of the American Philological Association. The Johns Hopkins University Press. Visions of the Divine from East and West. New York State University Press. The Rape of Medusa in the Temple of Athena: Aspects of Triangulation in the Girl.
The International Journal of Psychoanalysis. Indo-European Poetry and Myth. Archived from the original on 15 August Retrieved 1 June A Culture of Peru.
The Spirit of Ancient Peru: The Ancient Maya 6th fully revised ed. Asian Pacific Journal of Tropical Medicine. Capula, Massimo; Behler The Atlas of Snakes of the World. Cogger, Harold ; Zweifel, Richard Conant, Roger ; Collins, Joseph The Worship of the Serpent. In addition, salmonella, a bacterial disease, is sometimes picked up from a reptile's skin when touching a reptile kept as a pet.
Hylonomus, the oldest-known reptile, was about 8 to 12 inches 20 to 30 cm long. Westlothiana, also suggested as the oldest reptile, is for the moment considered to be related more to amphibians than to amniotes. Other examples of fossil animals considered to be ancient reptiles are those of the genera Petrolacosaurus, Araeoscelis, Paleothyris, Ophiacodontidae, Archaeothyris, and Ophiacodon, and also the family of mesosaurs.
The first true "reptiles" or amniotes are categorized as Anapsids Anapsida , which are vertebrates characterized by solid skulls with the conventional openings for nose, eyes, spinal cord, and so forth, but lacking temporal fenestrae jaw muscle attachment sites at holes in the sides of the skull behind the eyes near the temples.
Turtles are believed by some to be surviving anapsids, indeed the only surviving anapsids, as they also share this skull structure. However, this point has become contentious, with some arguing that turtles reverted to this primitive state in the process of improving their armor. Both sides have marshaled evidence, and the conflict has yet to be resolved. Shortly after the appearance in the fossil record of the first reptiles, a second branch appeared. The original branch led to the Anapsida, which did not develop the jaw muscle attachment holes in their skulls, and the second led to the Diapsida diapsids , which developed two pairs of jaw muscle attachment holes in their skulls behind the eye holes.
Diapsids "two arches" are a group of tetrapod animals that appeared in the fossil record about million years ago during the late Carboniferous period.
Living diapsids are extremely diverse, and are considered to include all birds , crocodiles, lizards, snakes, and tuataras and possibly even turtles. While some lost either one hole lizards , or both holes snakes , they are still classified as diapsids based on their assumed ancestry. During the Permian period million years ago , the Diapsida line of descent split into two lineages: The lepidosaurs modern snakes, lizards, and tuataras, as well as, debatably, the extinct sea reptiles of the Mesozoic era and the archosaurs living crocodilians and birds as well as the extinct pterosaurs and dinosaurs.
The earliest solid-skulled amniotes in addition to giving rise to the anapsids, are also considered to have given rise about million years ago to a separate line, the Synapsida synapsids , which have a pair of holes in their skulls behind and above the eyes; this feature has the advantage of lightening the skull and increasing the space for jaw muscles.
The synapsids eventually evolved into mammals and the early synapsids have been referred to as mammal-like reptiles by some specialists, while others argue that even the early synapsids were no longer reptiles. As noted above, from the classical standpoint, reptiles included all the amniotes except birds and mammals. Thus, reptiles were defined as the set of animals that includes crocodiles , alligators , tuatara, lizards , snakes , amphisbaenians , and turtles , grouped together as the class Reptilia Latin repere, "to creep".
This is still the usual definition of the term. However, in recent years, many taxonomists have begun to insist that for clear identification of the ancestor-descendant relations of all organisms each defined taxon should be monophyletic, that is, each taxon should include all the descendants from the originating stock.
The reptiles as defined are clearly not monophyletic but rather are paraphyletic , since they exclude both birds and mammals, although these also are considered to be descendant from the original reptile.
Colin Tudge writes:. Mammals are a clade [a monophyletic taxon], and therefore the cladists are happy to acknowledge the traditional taxon Mammalia ; and birds, too, are a clade, universally ascribed to the formal taxon Aves. Mammalia and Aves are, in fact, subclades within the grand clade of the Amniota. But the traditional class Reptilia is not a clade. It is just a section of the clade Amniota: The section that is left after the Mammalia and Aves have been hived off.
It cannot be defined by synamorphies, as is the proper way. It is instead defined by a combination of the features it has and the features it lacks: Reptiles are the amniotes that lack fur or feathers. Some cladists thus redefine Reptilia as a monophyletic group, including the classic reptiles as well as the birds and perhaps the mammals depending on ideas about their relationships.
Others abandon it as a formal taxon altogether, dividing it into several different classes. However, other biologists believe that the common characters of the standard four orders Crocodilia crocodiles , Rhynchocephalia tuataras , Squamata snakes and lizards , and Testudines turtles are more important than the exact relationships, or feel that redefining the Reptilia to include birds and mammals would be a confusing break with tradition. A number of biologists have adopted a compromise system, marking paraphyletic groups with an asterisk, for example, class Reptilia.
Colin Tudge notes other uses of this compromise system:. College-level references, such as Benton , offer another compromise by applying traditional ranks to accepted phylogenetic relationships. In this case, reptiles belong to the class Sauropsida, and mammal-like reptiles to the class Synapsida, with birds and mammals separated into their own traditional classes.
The terms Sauropsida "Lizard Faces" and Theropsida "Beast Faces" were coined to distinguish between lizards, birds, and their relatives on one hand Sauropsida and mammal-like reptiles and mammals Theropsida on the other.
This classification supplemented, but was never as popular as the classification of the reptiles according to the positioning of temporal fenestrae mentioned above under evolution of the reptiles Anapsida, Diapsida, Synapsida, and so on. A diverse group of egg-laying vertebrate animals, the Sauropsida includes all modern and most extinct "reptiles" excluding synapsids.
Living sauropsids include lizards, snakes, turtles, crocodiles, and birds. Extinct sauropsids include dinosaurs except birds , pterosaurs , plesiosaurs , ichthyosaurs , and many others.
The synapsids were originally defined, at the turn of the twentieth Century, as one of the five main subclasses of reptiles on the basis of their distinctive temporal openings. The synapsids represented the reptilian lineage that led to the mammals, and gradually evolved increasingly mammalian features, hence, "mammal-like reptiles.
In the current cladistic based system, the Linnean classification of the class Reptilia in terms of four sub-classes has been replaced. The term "Theropsida" is replaced by Synapsida, which now refers to both the old subclass Synapsida and the mammals. In the new edition of his textbook , Michael Benton uses the term "Class Sauropsida" to refer to all non-synapsid reptiles.
Because synapsids evolved into mammals, the mammals therefore are included under the clade Synapsida. That is, "synapsids" are now also known as "theropsids. The following is a very abbreviated classification of the extensive classification system presented by Benton The following classification of living reptiles was given by Uetz , which was modified from the overall taxonomy of Zug et al.
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Some restrictions may apply to use of individual images which are separately licensed. They have color vision with the visual depth perception being much more advanced than Amphibians and many Mammals. The vision is reduced in species like the Blind Snake, while some snakes have extra visual or sensory organs that make them sensitive to heat and infrared radiation. The horny epidermis layer makes their skin watertight, allowing these animals to inhabit dry land.
Reptiles have thinner skin compared to mammals and it also lacks the dermal layer present in mammal skin. The exposed skin areas are covered in scutes or scales which may have a bony base, creating their armors.
In turtles, a hard shell made up of fused scutes covers the entire body. Reptiles use their lungs for breathing. The skin of the aquatic turtles is more permeable for allowing them to respire while the cloaca is modified in various species to increase the gas exchange area. Despite these adaptations, lungs remain a very important part of their respiratory system. The main Reptile groups accomplish lung ventilation in different procedures. Squamates are known to ventilate the lugs mainly by their axial musculature.
Certain lizard species are capable of buccal pumping apart from the normal axial breathing. The proto-diaphragm in Tegu lizards separates their pulmonary cavity from visceral cavity, helping with their respiration by allowing greater lung inflation. The muscular structure of the diaphragm in the Crocodilians species resembles that of various mammals.
However, there are some differences in their diaphragmatic setup. They also have two aortas playing a major role in their systemic circulation. The oxygenated and deoxygenated blood may get mixed with each other in their three-chambered heart with the level of mixing depending on the species and the physiological state of the animal.
Their circulatory system is capable of shunting back the deoxygenated blood to the body and the oxygenated blood to the lungs if necessary. Unlike other Reptiles, animals in the crocodilian subgroup have four-chambered hearts. But, their two systemic aortas are only capable of bypassing their pulmonary circulation. On the other hand, the three-chambered hearts in various lizard and snake species can function as the four-chambered ones during contraction.
Majority of these animals have short digestive tracts because their diet mainly consists of meat, which is very simple to digest. Their digestion process is slower than that in mammals due to their inability of mastication and their low metabolism rate while resting.
The energy requirements for their poikilotherm metabolism are very low which allows large animals from this class such as various constrictors and crocodiles to survive for months from one large meal, digesting it slowly. Herbivorous reptiles are also unable to masticate their food, which slows down the digestive process. Some species are known to swallow pebbles and rocks that help in grinding up plant matters within the stomach, assisting their digestion.
The basic nervous system in the Reptiles is similar to that in the Amphibians. But, Reptiles have slightly larger cerebrum and cerebellum. Most of the important sensory organs are properly developed in these creatures. However, there are certain exceptions such as the absence of external ears in snakes they have the inner and middle ears. Reptiles have twelve cranial nerve pairs.
They have to use electrical tuning for expanding the range of their audible frequencies because they have short cochlea. These animals are believed to be less intelligent compared to mammals and birds because the relative size of their brain and body is much smaller than that of the latter.
However, the brain development can be more complex in some larger Reptiles. Modern species also have pineal glands in their brains. Most of these animals are tetrapods, meaning they have four legs. Snakes are examples of legless Reptiles. Their skeletal system is similar to other tetrapods with a spinal column supporting their bodies. Their excretory system consists of two small kidneys. The diapsid species excrete uric acid as the principal nitrogenous waste product.
But, turtles excrete mainly urea. Some of these species use their colons for reabsorbing water, while some are able to absorb the water stored in their bladders. Certain Reptiles excrete the excess salts in their bodies through the lingual and nasal salt glands.
Reptiles have certain characteristic features that help in distinguishing them from Amphibians, Mammals and Aves:. They are capable of adapting to almost all kinds of habitats and environmental conditions, except for extremely cold regions. These animals can inhabit dry deserts, forests, grasslands, wet meadows, shrub lands and even marine habitats.
Reptiles are capable of adapting to extremely high temperatures because they are cold blooded. Various snakes including the Rattle Snakes and King Snakes as well as different lizards like the Gila Monsters live in desert habitats.
Grassland is another common type of habitat for various snakes and lizards e. Garter Snakes, Fox Snakes. The vegetation in this habitat attracts many insects and rodents, making it easier for the Reptiles to catch prey.
Swamps and large water bodies are inhabited by different Reptiles such as crocodiles, alligators, certain turtles and snakes. Animals like the Saltwater Crocodile and Marine Iguana inhabit seaside, travelling in and out of ocean as necessary.
Some species, such as the Sea Snakes and Sea Turtles, live in the ocean. They leave the waters only during the breeding season for laying eggs. These animals typically practice sexual reproduction with some specific species using asexual reproduction. Majority of these animals are amniotes, laying eggs covered with calcareous or leathery shells. The eggs are generally laid in underground burrows dug by the females.
The viviparity and ovoviviparity modes of reproduction are used by many species such as all boas and many vipers. However, the level of viviparity may vary with some species retaining their eggs until shortly before hatching while others nourish the eggs for supplementing the yolks.
In some Reptile species, the eggs do not have any yolk with the adults providing all the necessary nourishment through a structure resembling the mammalian placenta. Six lizard families and one snake family from the Squamata sub-group are known to be capable of agamogenesis or asexual reproduction.