Hydrodynastes gigas is a New World species of large, rear-fanged, Dipsadin snake endemic to South America. It is commonly and alternatively known as the false water cobra and the Brazilian smooth snake.[3] The false water cobra is so named because when the snake is threatened it "hoods" as a true cobra (Naja species) does. Unlike a true cobra, though, it does not rear up, but remains in a horizontal position. No subspecies are currently recognized as being valid.[4]
Hydrodynastes gigas is commonly referred to as the false water cobra, false cobra, South American water cobra,[3] and Brazilian smooth snake. In South America, it is sometimes referred to as boipevassu.[5] Additional South American common names include mboi-peba, ñacaniná, surucucu-do-pantanal, vibora ladradora (barking snake), and yacanina.[6]
Description
H. gigas is a large dipsadidae snake that may exceed 3 m (9 to 10 ft) in total length (including tail) when adult.[3] Most H. gigas snakes reach about 2 m (6 to 7 ft) in total length.[5][7] It is of medium body, so is neither particularly heavy nor slender-bodied, Weights can average around 1.6 kg (3.5 lb) and exceed 2 kg (4.4 lb) in mature adults, with some specimens weighing 4.56 kg (10.1 lb).[8][9] Males are typically much smaller than females in this species. The common name false water cobra is an allusion to its ability to flatten its neck, similar to a cobra, as a defensive reaction to make it look larger and more intimidating.[7] Unlike the true cobra, though, the false water cobra stays in a horizontal position when it hoods, rather than rearing into a vertical position.[10]H. gigas can flatten not only its neck, but also lower down its body, which is not possible for a true cobra.
A pair of specimens on display at the Smithsonian National Zoological Park, Washington, DC
Additionally, the pattern and coloration of this Hydrodynastes species superficially resemble those of true water cobras (Boulengerina). The false water cobra has large eyes with circular pupils, allowing good daytime vision. The tongue is black, and of the typical snake fashion.
The background colour of a mature specimen is an olive green or brown, with dark spots and bands covering much of its body.[5] The background coloring and banding generally become darker towards the tail. This colouring gives the false water cobra effective camouflage in its natural rainforest environment. The ventral scales are yellow or brown, spotted with dark flecks that make three dotted lines, which appear to merge towards the tail. Mehrtens, 1987, suggested females are brown ventrally, whilst males are yellow.[5] Females are suggested to have lighter bands and markings on their bodies.[5] This is not an effective way of judging the sex of H. gigas, as coloring differs slightly between all individuals. Hatchlings and juveniles are much darker in coloration and do not have the typical dark eyes of the adults. They more resemble a garter or water snake than their mature counterparts. In captivity, hypomelanstic animals have been produced. These animals vary in coloration, from some having only slightly lighter colored saddles, to those that are almost patternless. A melanistic population found in Tocantins, central Brazil, was originally describe as a new species of Hydrodynastes, H. melanogigas, but genetic evidence indicates that this population is composed of melanisticH. gigas.[11]
H. gigas generally lives in wet, humid areas, and marshlands,[5] typically within the tropical rainforests that are common within its range. However, the false water cobra has also been observed in dryer areas,[5] although this is not its preferred habitat. The preference of wetlands as a habitat for H. gigas contributes to its common name of false "water" cobra.
Behavior
H. gigas is primarily a diurnal species. It is also a very active and inquisitive snake, which spends much of the day climbing, burrowing, and even swimming. Temperaments can vary considerably between specimens; some are very docile and reluctant to bite, whilst others are very defensive and even aggressive or intimidating.[5] Captive-bred specimens can become quite tame and trusting, and many exhibit a high level of intelligence.
Feeding
In the wild, H. gigas primarily feeds on fish and amphibians, but will take small mammals, rodents, birds, and even other reptiles. In captivity, they can be introduced to other types of food, as well.
Venom
The posterior maxillary teeth of H. gigas are enlarged, and the Duvernoy's gland produces a secretion with high proteolytic activity. Besides the ability of this large and powerful snake to inflict mechanical trauma, numerous cases of local envenomation and perhaps hypersensitivity have occurred, most of which have gone unreported. Prolonged, chewing bites may result in painful (sometimes extensive and persistent) swelling, as well as bruising.[3] Nevertheless, the species is regularly kept as a pet, becoming increasingly popular in recent years.[citation needed]
Manning et al. (1999) described a case in which an 18-year-old male pet-store employee was bitten on the wrist by a specimen that hung on for 1.5 minutes. Some mild swelling resulted, but after nine hours, the victim claimed to have experienced three bouts of muscle paralysis, during which he fell and was unable to move or speak, but a medical examination did not produce any unusual results. The symptoms described possibly were the result of anxiety.[3] The liquid venom yield ranges from 0-50 microliters and the solid venom yield is 1.3 mg.[12]
Taxonomy
This species was once considered to constitute a single monotypic genus, Cyclagras[13]
^"Hydrodynastes gigas ". The Reptile Database. www.reptile-database.org.
^ abcdeWarrell DA (2004). "Snakebites in Central and South America: Epidemiology, Clinical Features, and Clinical Management". In:Campbell JA, Lamar WW (2004). The Venomous Reptiles of the Western Hemisphere. Ithaca and London: Comstock Publishing Associates. 870 pp., 1,500 plates. ISBN0-8014-4141-2.
^ abcdefgh. Archived from the original on 2009-01-07. Retrieved 2009-06-23.
^ abFreiberg M (1982). Snakes of South America. Hong Kong: T.F.H. Publications. 189 pp. ISBN0-87666-912-7. (Hydrodynastes gigas, pp. 78-79, 99, 132-133 + photographs on pp. 5, 50).
^ ab. Archived from the original on 2008-07-05. Retrieved 2009-06-15.
^Loughman, Z. J. (2020). Utilization of Natural History Information in Evidence based Herpetoculture: A Proposed Protocol and Case Study with Hydrodynastes gigas (False Water Cobra). Animals, 10(11), 2021.
^Martinelli, I. M. (2011). 290 290 NATURAL HISTORY NOTES. Herpetological Review, 42, 2.
^Carvalho, P., Zaher, H., da Silva, Jr., N., and Santana, D (2020). A morphological and molecular study of Hydrodynastes gigas (Serpentes, Diapsadidae), a widespread species from South America. PeerJ. 8:e10073.
^Weinstein, Scott A.; Warrell, David A.; Keyler, Daniel E. (2011-06-20). "Venomous Bites from Non-Venomous Snakes: A Critical Analysis of Risk and Management of "Colubrid Snake Bites. Elsevier. ISBN978-0-12-387755-0.
^Dowling HG, Gibson FW (1970). "The relationships of the Neotropical snakes Hydrodynastes bicinctus and Cyclagras gigas ". Herpetological Review2 (2): 37-38.
Further reading
Boulenger GA (1894). Catalogue of the Snakes in the British Museum (Natural History). Volume II., Containing the Conclusion of the Colubridæ Aglyphæ. London: Trustees of the British Museum (Natural History). (Taylor and Francis, printers). xi + 382 pp. + Plates I-XX. (Genus Cyclagras and species Cyclagras gigas, p. 144).
Duméril A-M-C, Bibron G, Duméril A[-H-A] (1854). Erpétology générale ou histoire naturelle complète des reptiles. Tome septième. Première partie. [= General Herpetology or Complete Natural History of the Reptiles. Volume 7. Part 1.] Paris: Roret. xvii + 780 pp. (Xenodon gigas, pp. 761–763).
External links
Wikimedia Commons has media related to Hydrodynastes gigas.
Hydrodynastes gigas at the Reptarium.cz Reptile Database. Accessed 27 September 2007.
May 05, 2023
hydrodynastes, gigas, world, species, large, rear, fanged, dipsadin, snake, endemic, south, america, commonly, alternatively, known, false, water, cobra, brazilian, smooth, snake, false, water, cobra, named, because, when, snake, threatened, hoods, true, cobra. Hydrodynastes gigas is a New World species of large rear fanged Dipsadin snake endemic to South America It is commonly and alternatively known as the false water cobra and the Brazilian smooth snake 3 The false water cobra is so named because when the snake is threatened it hoods as a true cobra Naja species does Unlike a true cobra though it does not rear up but remains in a horizontal position No subspecies are currently recognized as being valid 4 Hydrodynastes gigasConservation statusCITES Appendix II CITES 1 Scientific classificationKingdom AnimaliaPhylum ChordataClass ReptiliaOrder SquamataSuborder SerpentesFamily ColubridaeGenus HydrodynastesSpecies H gigasBinomial nameHydrodynastes gigas A M C Dumeril Bibron amp A H A Dumeril 1854 Synonyms 2 Xenodon gigas A M C Dumeril Bibron amp A H A Dumeril 1854 Cyclagras gigas Cope 1885 Hydrodynastes gigas Hoge 1966 Hydrodynastes melanogigas Franco Fernandes amp Bentim 2007 Contents 1 Common names 2 Description 3 Geographic range 4 Habitat 5 Behavior 6 Feeding 7 Venom 8 Taxonomy 9 References 10 Further reading 11 External linksCommon names EditHydrodynastes gigas is commonly referred to as the false water cobra false cobra South American water cobra 3 and Brazilian smooth snake In South America it is sometimes referred to as boipevassu 5 Additional South American common names include mboi peba nacanina surucucu do pantanal vibora ladradora barking snake and yacanina 6 Description EditH gigas is a large dipsadidae snake that may exceed 3 m 9 to 10 ft in total length including tail when adult 3 Most H gigas snakes reach about 2 m 6 to 7 ft in total length 5 7 It is of medium body so is neither particularly heavy nor slender bodied Weights can average around 1 6 kg 3 5 lb and exceed 2 kg 4 4 lb in mature adults with some specimens weighing 4 56 kg 10 1 lb 8 9 Males are typically much smaller than females in this species The common name false water cobra is an allusion to its ability to flatten its neck similar to a cobra as a defensive reaction to make it look larger and more intimidating 7 Unlike the true cobra though the false water cobra stays in a horizontal position when it hoods rather than rearing into a vertical position 10 H gigas can flatten not only its neck but also lower down its body which is not possible for a true cobra A pair of specimens on display at the Smithsonian National Zoological Park Washington DC Additionally the pattern and coloration of this Hydrodynastes species superficially resemble those of true water cobras Boulengerina The false water cobra has large eyes with circular pupils allowing good daytime vision The tongue is black and of the typical snake fashion The background colour of a mature specimen is an olive green or brown with dark spots and bands covering much of its body 5 The background coloring and banding generally become darker towards the tail This colouring gives the false water cobra effective camouflage in its natural rainforest environment The ventral scales are yellow or brown spotted with dark flecks that make three dotted lines which appear to merge towards the tail Mehrtens 1987 suggested females are brown ventrally whilst males are yellow 5 Females are suggested to have lighter bands and markings on their bodies 5 This is not an effective way of judging the sex of H gigas as coloring differs slightly between all individuals Hatchlings and juveniles are much darker in coloration and do not have the typical dark eyes of the adults They more resemble a garter or water snake than their mature counterparts In captivity hypomelanstic animals have been produced These animals vary in coloration from some having only slightly lighter colored saddles to those that are almost patternless A melanistic population found in Tocantins central Brazil was originally describe as a new species of Hydrodynastes H melanogigas but genetic evidence indicates that this population is composed of melanistic H gigas 11 Geographic range EditIn South America H gigas is found from eastern Bolivia to southern Brazil and in Paraguay and Argentina 6 Habitat EditH gigas generally lives in wet humid areas and marshlands 5 typically within the tropical rainforests that are common within its range However the false water cobra has also been observed in dryer areas 5 although this is not its preferred habitat The preference of wetlands as a habitat for H gigas contributes to its common name of false water cobra Behavior EditH gigas is primarily a diurnal species It is also a very active and inquisitive snake which spends much of the day climbing burrowing and even swimming Temperaments can vary considerably between specimens some are very docile and reluctant to bite whilst others are very defensive and even aggressive or intimidating 5 Captive bred specimens can become quite tame and trusting and many exhibit a high level of intelligence Feeding EditIn the wild H gigas primarily feeds on fish and amphibians but will take small mammals rodents birds and even other reptiles In captivity they can be introduced to other types of food as well Venom EditThe posterior maxillary teeth of H gigas are enlarged and the Duvernoy s gland produces a secretion with high proteolytic activity Besides the ability of this large and powerful snake to inflict mechanical trauma numerous cases of local envenomation and perhaps hypersensitivity have occurred most of which have gone unreported Prolonged chewing bites may result in painful sometimes extensive and persistent swelling as well as bruising 3 Nevertheless the species is regularly kept as a pet becoming increasingly popular in recent years citation needed Manning et al 1999 described a case in which an 18 year old male pet store employee was bitten on the wrist by a specimen that hung on for 1 5 minutes Some mild swelling resulted but after nine hours the victim claimed to have experienced three bouts of muscle paralysis during which he fell and was unable to move or speak but a medical examination did not produce any unusual results The symptoms described possibly were the result of anxiety 3 The liquid venom yield ranges from 0 50 microliters and the solid venom yield is 1 3 mg 12 Taxonomy EditThis species was once considered to constitute a single monotypic genus Cyclagras 13 References Edit Appendices CITES cites org Retrieved 2022 01 14 Hydrodynastes gigas The Reptile Database www reptile database org a b c d e Warrell DA 2004 Snakebites in Central and South America Epidemiology Clinical Features and Clinical Management In Campbell JA Lamar WW 2004 The Venomous Reptiles of the Western Hemisphere Ithaca and London Comstock Publishing Associates 870 pp 1 500 plates ISBN 0 8014 4141 2 Hydrodynastes gigas Integrated Taxonomic Information System Retrieved 9 February 2007 a b c d e f g h False Water Cobras Cyclagras Hydronastes gigas Archived from the original on 2009 01 07 Retrieved 2009 06 23 a b Freiberg M 1982 Snakes of South America Hong Kong T F H Publications 189 pp ISBN 0 87666 912 7 Hydrodynastes gigas pp 78 79 99 132 133 photographs on pp 5 50 a b FWC care sheet wanted please help Reptile Forums UK Archived from the original on 2008 07 05 Retrieved 2009 06 15 Loughman Z J 2020 Utilization of Natural History Information in Evidence based Herpetoculture A Proposed Protocol and Case Study with Hydrodynastes gigas False Water Cobra Animals 10 11 2021 Martinelli I M 2011 290 290 NATURAL HISTORY NOTES Herpetological Review 42 2 Untitled Document Archived from the original on 2008 12 11 Carvalho P Zaher H da Silva Jr N and Santana D 2020 A morphological and molecular study of Hydrodynastes gigas Serpentes Diapsadidae a widespread species from South America PeerJ 8 e10073 Weinstein Scott A Warrell David A Keyler Daniel E 2011 06 20 Venomous Bites from Non Venomous Snakes A Critical Analysis of Risk and Management of Colubrid Snake Bites Elsevier ISBN 978 0 12 387755 0 Dowling HG Gibson FW 1970 The relationships of the Neotropical snakes Hydrodynastes bicinctus and Cyclagras gigas Herpetological Review 2 2 37 38 Further reading EditBoulenger GA 1894 Catalogue of the Snakes in the British Museum Natural History Volume II Containing the Conclusion of the Colubridae Aglyphae London Trustees of the British Museum Natural History Taylor and Francis printers xi 382 pp Plates I XX Genus Cyclagras and species Cyclagras gigas p 144 Dumeril A M C Bibron G Dumeril A H A 1854 Erpetology generale ou histoire naturelle complete des reptiles Tome septieme Premiere partie General Herpetology or Complete Natural History of the Reptiles Volume 7 Part 1 Paris Roret xvii 780 pp Xenodon gigas pp 761 763 External links Edit Wikimedia Commons has media related to Hydrodynastes gigas Hydrodynastes gigas at the Reptarium cz Reptile Database Accessed 27 September 2007 Retrieved from https en wikipedia org w index php title Hydrodynastes gigas amp oldid 1143896631, wikipedia, wiki, book, books, library,
