Snakes are elongated, legless, carnivorous reptiles of the suborder Serpentes that can be distinguished fromlegless lizards by their lack of eyelids and external ears. Like all squamates, snakes are ectothermic, amniotevertebrates covered in overlapping scales. Many species of snakes have skulls with several 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 ofvestigial claws on either side of the cloaca.
Living snakes are found on every continent except Antarctica, in the Pacific and Indian Oceans, and on most smaller land masses — exceptions include some large islands, such as Ireland and New Zealand, and many small islands of the Atlantic and central Pacific. More than 20 families are currently recognized, comprising about 500 genera and about 3,400 species. They range in size from the tiny, 10 cm-long thread snake to theReticulated python of up to 8.7 meters (29 ft) in length. The fossil species Titanoboa cerrejonensis was 15 meters (49 ft) long. Snakes are thought to have evolved from either burrowing or aquatic lizards during the mid-Cretaceousperiod, and the earliest known fossils date to around 112 Ma ago. The diversity of modern snakes appeared during the Paleocene period (c 66 to 56 Ma ago). The oldest preserved descriptions of snakes can be found in theBrooklyn Papyrus.
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.
An anaconda is a large, non-venomous snake found in tropical South America. Although the name applies to a group of snakes, it is often used to refer only to one species in particular, the common or green anaconda, Eunectes murinus, which is one of the largest snakes in the world.
Anaconda may refer to:
- Any member of the genus Eunectes, a group of large, aquatic snakes found in South America
- Eunectes murinus, the green anaconda, the largest species, is found east of the Andes in Colombia, Venezuela, the Guianas, Ecuador, Peru, Bolivia, Brazil and Trinidad and Tobago.
- Eunectes notaeus, the yellow anaconda, a small species, is found in eastern Bolivia, southern Brazil, Paraguay and northeastern Argentina.
- Eunectes deschauenseei, the darkly-spotted anaconda, is a rare species found in northeastern Brazil and coastal French Guiana.
- Eunectes beniensis, the Bolivian anaconda, the most recently defined species, is found in the Departments of Beni and Pando in Bolivia.
- The giant anaconda is a mythical snake of enormous proportions said to be found in South America.
- Any large snake that "constricts" its prey (see Constriction), if applied loosely, could be called anaconda.
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Etymology
Although the name refers to a snake found only in South America, the name commonly used in Brazil is sucuri, sucuriju or sucuriuba. The South American namesanacauchoa and anacaona were suggested in an account by Peter Martyr d'Anghiera but the idea of a South American origin was questioned by Henry Walter Bateswho, in his travels in South America, failed to find any similar name in use. The word anaconda is derived from the name of a snake from Ceylon (Sri Lanka) thatJohn Ray described in Latin in his Synopsis Methodica Animalium (1693) as serpens indicus bubalinus anacandaia zeylonibus, ides bubalorum aliorumque jumentorum membra conterens. Ray used a catalogue of snakes from the Leyden museum supplied by Dr. Tancred Robinson but the description of its habit was based on Andreas Cleyer who in 1684 described a gigantic snake that crushed large animals by coiling and crushing their bones. Henry Yule in his Hobson-Jobsonnotes that the word became more popular due to a piece of fiction published in 1768 in the Scots Magazine by a certain R. Edwin. Edwin described a tyger being crushed and killed by an anaconda when in fact tigers never occurred in Sri Lanka. Yule and Frank Wall noted that the snake was in fact a python and suggested a Tamil origin anai-kondra meaning elephant killer. A Sinhalese origin was suggested by Donald Ferguson who pointed out that the word Henakandaya (henalightning and kanda stem/trunk) was used in Sri Lanka for the small whip snake (Ahaetulla pulverulenta) and somehow got misapplied to the python before myths were created.
