Western green mamba: Difference between revisions
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| name = Western green mamba |
| name = Western green mamba |
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| image = Dendroaspis viridisPCCA20051227-1885B.jpg |
| image = Dendroaspis viridisPCCA20051227-1885B.jpg |
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| status = LC |
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| status_ref = <ref name='IUCN'/> |
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| status_system = iucn3.1 |
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| regnum = [[Animal]]ia |
| regnum = [[Animal]]ia |
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| phylum = [[Chordate|Chordata]] |
| phylum = [[Chordate|Chordata]] |
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The '''Western green mamba''' (''Dendroaspis viridis''), also known as the '''West African green mamba''' or '''Hallowell's green mamba''',<ref name="WCH">{{cite web|title=Dendroaspis viridis|url=http://www.toxinology.com/fusebox.cfm?fuseaction=main.snakes.display&id=SN0171|work=Clinical Toxinology Resource|publisher=University of Adelaide|accessdate=4 March 2014}}</ref> is a long, thin and highly [[venomous snake]] of the genus ''Dendroaspis'' ([[Mamba]]s).<ref name="Hallowell">{{cite book | |
The '''Western green mamba''' (''Dendroaspis viridis''), also known as the '''West African green mamba''' or '''Hallowell's green mamba''',<ref name="WCH">{{cite web|title=Dendroaspis viridis|url=http://www.toxinology.com/fusebox.cfm?fuseaction=main.snakes.display&id=SN0171|work=Clinical Toxinology Resource|publisher=University of Adelaide|accessdate=4 March 2014}}</ref> is a long, thin and highly [[venomous snake]] of the genus ''Dendroaspis'' ([[Mamba]]s).<ref name="Hallowell">{{cite book | ISSN=0097-3157 | LCCN=12030019 //r24 | OCLC=1382862 | url=http://ia700202.us.archive.org/2/items/proceedingsofaca02acaduoft/proceedingsofaca02acaduoft.pdf | title=Description of new species of African reptiles. | publisher=Proceedings of the National Academy of Sciences (Stanford University's Highwire Press) | last=Hallowell | first=E. | year=1844 | volume=2 | location=Philadelphia, USA | pages=169–172}}</ref> The Western green mamba is a fairly large and predominantly arboreal species, capable of navigating through trees swiftly and gracefully. This species will also descend to ground level where it actively pursues and hunts prey items such as [[rodents]] and other small mammals. The Western green mamba is a very alert, nervous and extremely agile snake that lives mainly in the coastal [[tropical rainforest]], thicket, and woodland regions of [[western Africa]].<ref name=S&B95>{{cite book|last=Spawls, S.|first=Branch, B.|title=The Dangerous Snakes of Africa|date=1995|publisher=Blandford|isbn=978-0-88359-029-4|pages=51-52}}</ref> Like all the other mambas, the Western green mamba is a highly venomous elapid species. Its venom is a potent mixture of rapid-acting pre-snaptic and postsynaptic [[neurotoxins]], [[Cardiotoxicity|cardiotoxin]]s and fasciculins. This is not a particularily aggressive snake and conflict with humans is minimal. As a result, bites to people by this species are quite uncommon. Nevertheless, mortality rates are very high as bites attributed to this species have occurred and many of the recorded bites have often been fatal. Rapid progression of severe life-threatening symptoms are hallmarks of mamba bites. Bites with envenomation can be rapidly fatal. Case reports of rapidly fatal outcomes, in as little as 30 minutes, have been recorded for this species.<ref name=WGMBite>{{cite web|title=Immediate First Aid for bites by Western Green Mamba (Dendroaspis viridis)|url=http://toxicology.ucsd.edu/Snakebite%20Protocols/Dendroa4.htm|work=Toxicology|publisher=University of California, San Diego|accessdate=4 March 2014}}</ref> |
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==Etymology== |
==Etymology== |
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The Western green mammba is classified under the [[genus]] ''[[Dendroaspis]]'' of the family [[Elapidae]]. ''Dendroaspis viridis'' was first described by the [[United States|American]] herpetologist and physician [[Edward Hallowell (herpetologist)|Edward Hallowell]] in 1844.<ref name="ITIS"/><ref name=EH1844>{{cite journal|last=Hallowell|first=E.|title=Description of new species of African reptiles|journal=Proceedings of the Academy of Natural Sciences of Philadelphia|date=December, 1844|volume=v. 2 (1844-1845)|pages=169-172|url=http://ia700202.us.archive.org/2/items/proceedingsofaca02acaduoft/proceedingsofaca02acaduoft.pdf|accessdate=4 March 2014}}</ref> The [[genus|generic name]], ''Dendroaspis'', is derived from [[Ancient Greek]] words – ''Dendro'', which means "tree",<ref name=Dendro>{{cite web|title=dendro-|url=http://dictionary.reference.com/browse/dendro-|work=Collins English Dictionary - Complete & Unabridged 10th Edition|publisher=HarperCollins Publishers|accessdate=4 March 2014}}</ref> and ''aspis'' ('''ασπίς''') or "asp", which' is understood to mean "shield", but it also designate "cobra" or simply "snake". In old text, ''aspis'' or asp was used to refer to Naja haje (in reference with the hood, like a shield).<ref name=asp>{{cite web|title=aspis, asp|url=http://dictionary.reference.com/browse/asp|work=Dictionary.com Unabridged|publisher=Random House |accessdate=4 March 2014}}</ref> Thus, "Dendroaspis" literally means ''tree snake'', which refers to the arboreal nature of most of the species within the genus. Schlegel used the name Dendroaspis, significant ''tree cobra''. The [[Species|specific name]] ''viridis'' is of Latin origin and means "green".<ref name=viridis>{{cite web|title=Definition of "viridis"|url=http://latinlexicon.org/definition.php?p1=1017588|work=Numen - The Latin Lexicon|publisher=http://latinlexicon.org/index.php|accessdate=4 March 2014}}</ref> |
The Western green mammba is classified under the [[genus]] ''[[Dendroaspis]]'' of the family [[Elapidae]]. ''Dendroaspis viridis'' was first described by the [[United States|American]] herpetologist and physician [[Edward Hallowell (herpetologist)|Edward Hallowell]] in 1844.<ref name="ITIS"/><ref name=EH1844>{{cite journal|last=Hallowell|first=E.|title=Description of new species of African reptiles|journal=Proceedings of the Academy of Natural Sciences of Philadelphia|date=December, 1844|volume=v. 2 (1844-1845)|pages=169-172|url=http://ia700202.us.archive.org/2/items/proceedingsofaca02acaduoft/proceedingsofaca02acaduoft.pdf|accessdate=4 March 2014}}</ref> The [[genus|generic name]], ''Dendroaspis'', is derived from [[Ancient Greek]] words – ''Dendro'', which means "tree",<ref name=Dendro>{{cite web|title=dendro-|url=http://dictionary.reference.com/browse/dendro-|work=Collins English Dictionary - Complete & Unabridged 10th Edition|publisher=HarperCollins Publishers|accessdate=4 March 2014}}</ref> and ''aspis'' ('''ασπίς''') or "asp", which' is understood to mean "shield", but it also designate "cobra" or simply "snake". In old text, ''aspis'' or asp was used to refer to Naja haje (in reference with the hood, like a shield).<ref name=asp>{{cite web|title=aspis, asp|url=http://dictionary.reference.com/browse/asp|work=Dictionary.com Unabridged|publisher=Random House |accessdate=4 March 2014}}</ref> Thus, "Dendroaspis" literally means ''tree snake'', which refers to the arboreal nature of most of the species within the genus. Schlegel used the name Dendroaspis, significant ''tree cobra''. The [[Species|specific name]] ''viridis'' is of Latin origin and means "green".<ref name=viridis>{{cite web|title=Definition of "viridis"|url=http://latinlexicon.org/definition.php?p1=1017588|work=Numen - The Latin Lexicon|publisher=http://latinlexicon.org/index.php|accessdate=4 March 2014}}</ref> |
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==Biology== |
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Smaller than the [[black mamba]], but larger than the [[eastern green mamba]] and the [[Jameson's mamba]] the western green mamba is a long and very slender bodied snake with a long tapering tail. It is the largest of the [[arboreal]] mambas. The average length of an adult snake of this species is between {{convert|1.8|m|ft}} and {{convert|2.2|m|ft}}. Most are around {{convert|1.8|m|ft}}, but specimens measuring around {{convert|2|m|ft}} are quite common also. Some specimens of this species can grow to maximum lengths of {{convert|3.2|m|ft}}, making this species along with the [[forest cobra]] tied as the second longest [[venomous snake]]s in Africa.<ref name=DEVENOM/><ref name='WCH'/> The head is narrow and elongate, with a distinct canthus and slightly distinct from the neck. On rare occasions the neck may be flattened when the snake is aroused, but there is no hood. Eyes are medium in size with round pupils and a yellow brown iris.<ref name='WCH'/> Although the vast majority of specimens are greenish-yellow, olive green, or emerald green in colour, some specimens have shown different colouration. Although very rare, light blue or full yellow specimens do occur. The scales of the body of this species have a black edging. The dorsal scales of this snake are oblique, smooth, narrow, and exceptionally large for an [[elapid]].<ref name=DEVENOM/><ref name='WCH'/><ref name="ErZug">{{cite book |last= Ernst|first= Carl H.|last= Zug|first= George R.|title= Snakes in Question: The Smithsonian Answer Book |year= 1996|publisher= Smithsonian Institution Scholarly Press |location= Washington D.C., USA|isbn= 1-56098-648-4}}</ref> |
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===Identification and physical description=== |
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The western green mamba is a long and very slender bodied snake with a long tapering tail. The average length of an adult snake of this species is between {{convert|1.4|m|ft}} and {{convert|2.1|m|ft}}. Some specimens of this species can grow to maximum lengths of {{convert|2.4|m|ft}}.<ref name=S&B95/> The head is narrow and elongate, with a distinct canthus and slightly distinct from the neck. On rare occasions the neck may be flattened when the snake is aroused, but there is no hood. Eyes are medium in size with round pupils and a yellow brown iris. Dorsal surface body colour is vivid yellowish green to green with anterior margins of the scales yellow. In many specimens the posterior body and tail are yellow. In some specimens dorsal body scales are distinctly bordered with black forming chevron shaped markings. The black interstitial skin is clearly visible especially highlighting individual head scales and scales on the tail. Head dorsum is similar to dorsal surface anterior body colour or slightly darker green. Laterally the head scales, particularly the labials, are distinctly black edged and colouration is usually paler than dorsum or slightly yellowish tinted. When viewed from above the black edging of scales and black interstitial skin result in a plaited appearance. Head venter, throat, ventral and subcaudal surface colour is pale yellowish to yellowish green.<ref name="WCH"/> |
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===Scalation=== |
===Scalation=== |
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The head, body and tail scalation of the western green mamba:<ref name="WCH"/> |
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Dorsal scales at mid-body 13, ventrals 211-225, subcaudals 107-120, subcaudals are paired, anal plate is divided, upper labials 7-9, pre-oculars 3, post-oculars 3-4, lower labials 8-10, temporals 2+1 variable.<ref name=DEVENOM/> |
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{{col-begin|width=auto}} |
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{{col-break}} |
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* '''Dorsal at midbody:''' 11-15 (rarely 13) |
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* '''Ventral:''' 210-242 |
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* '''Subcaudal:''' 105–125 (paired) |
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* '''Anal plate:''' Divided |
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* '''Upper labials:''' 7-8 |
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{{col-break}} |
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* '''Upper labials to eye:''' 4th (4th and 5th) |
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* '''Preoculars:''' 2-3 |
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* '''Postoculars:''' 3-4 |
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* '''Lower labials:''' 11-13 |
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* '''Temporal:''' 2+2 (occasionally 2 + 3 or 2 + 4) |
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{{col-end}} |
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==Distribution and habitat== |
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===Geographic range=== |
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The western green mamba is native to [[West Africa]] can be found in [[Benin]], [[Cote d'Ivoire]] ( Ivory Coast ), [[Gambia]], [[Ghana]], [[Guinea]], [[Guinea-Bissau]], [[Liberia]], [[Senegal]], [[Sierra Leone]], and [[Togo]].<ref name="WCH"/> The species occurs from [[The Gambia|Gambia]] and southern [[Senegal]] to [[Benin]]. It is confined to the humid tropics, with records from [[Guinea-Bissau]], [[Guinea]], [[Sierra Leone]]<ref name=T&M06/> and [[Togo]]. In Togo it has a known northern limit to its distribution in Aledjo, but it might occur in forests of the more northerly Kara region <ref name="S et al."/> Old records from [[Nigeria]] are unreliable. It can also be found in the very southern tip of [[Mali]] along the border with Côte d’Ivoire, western [[Cameroon]] and [[Gabon]].<ref name="OSHEA">{{cite book | title=Venomous Snakes of the World | publisher=New Holland Publishers | last=O'Shea | first=M. | year=2005 | location=United Kingdom | isbn=0-691-12436-1}}</ref> |
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===Habitat=== |
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Western green mambas live mainly in the coastal tropical [[rainforest]], thicket, and woodland regions of western Africa. The majority of records from within the continuous forest block, but the Gambia and Guinea-Bissau records are from isolated forests. The species persists in areas where the tree cover has been removed, providing that sufficient hedges and thicket remain. Found in some suitably vegetated suburbs and towns and parklands therein.<ref name=S&B95/> Western green mambas are snakes of humid forest. This species is largely confined to areas where rainfall exceeds {{convert|1,500|mm|cm}}.<ref name=T&M06>{{cite book|last=Trape, JF.|first=Mané, Y.|title=Guide des serpents d'Afrique occidentale : Savane et désert|date=18 October 2006|publisher=IRD Orstom|isbn=978-2-70-991600-4}}</ref> In Togo, however, its range extends into the drier open forests of the north, the Guinean savannas of the west, and the littoral zone.<ref name="S et al.">{{cite journal|last=Segniagbeto|first=GH.|coauthors=Trape, J-F.; David, P.; Ohler, A.; Dubois, A.; Glitho, IA.|title=The snake fauna of Togo: systematics, distribution and biogeography, with remarks on selected taxonomic problems|journal=Zoosystema|date=September 2011|volume=33|issue=3|pages=325-360|doi=10.5252/z2011n3a4|accessdate=4 March 2014}}</ref> |
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The Western green mamba is native to [[West Africa]] and occurs in southern [[Senegal]], [[The Gambia|Gambia]], [[Guinea-Bissau]], [[Guinea]], [[Sierra Leone]], [[Liberia]], [[Côte d’Ivoire]], [[Ghana]], [[Togo]], [[Benin]], and southwest [[Nigeria]].<ref name='Davidson'>{{cite web|url=http://drdavidson.ucsd.edu/portals/0/snake/dendroa4.htm|title=IMMEDIATE FIRST AID|accessdate=2011-01-11|last=Davidson|first=Terence|publisher=University of California, San Diego}}</ref><ref name="OSHEA">{{cite book |last= O'Shea|first= Mark|title= Venomous Snakes of the World |date= 12 September 2005 |publisher= Princeton University Press |location= New Jersey, USA|isbn= 0-691-12436-1}}</ref> It can also be found in the very southern tip of [[Mali]] along the border with Côte d’Ivoire, western [[Cameroon]] and [[Gabon]].<ref name=DEVENOM>{{cite web|last=Mastenbroek|first=Richard|title=Captive Care of the Western Green Mamba|url=https://docs.google.com/viewer?a=v&q=cache:rX2Zb9EhCHwJ:devenomized.com/libraries/elapids/Green_Mamba.pdf+western+green+mamba&hl=en&gl=ca&pid=bl&srcid=ADGEESgjY0F_XMkFv7IOu71SSuah66vfQoc1dNHQlRk0PgRrlm1O0IhoL|work=Devenomoid Care|publisher=www.devenomized.com|accessdate=21 December 2011}}</ref><ref name="OSHEA"/> |
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===Conservation status=== |
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==Habitat== |
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This species is classified as [[Least Concern]] (LC) on the [[World Conservation Union|IUCN]] [[IUCN Red List|Red List of Threatened Species]] (v3.1, 2011). The conservation status of this species was last assessed in July 2012 and published in 2013, and it was classed as such due to a wide distribution, fairly generalist habits, stable population and the lack of major threats.<ref name='IUCN'>{{IUCN | id =13265799| taxon = Dendroaspis viridis | assessors = Luiselli, L. & Segniagbeto, G. | assessment_year =2012 | version = 3.1 | accessdate = 4 March 2014 }}</ref> |
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Western green mambas live mainly in the coastal tropical [[rainforest]], thicket, and woodland regions of western Africa.<ref name='WCH'/><ref name='Davidson'/> Although mainly found in dense and closed forests, these snakes can persist in areas where the tree cover has been removed, providing that sufficient hedges and thicket remain. In areas where there is very severe encroachment on their natural habitat or areas where vegetation or trees have been destroyed, these snakes will go into suitably vegetated city suburbs and towns often dwelling in the thickets of bushes or atop lush trees in parks and other well vegetated areas.<ref name=DEVENOM/> |
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==Behaviour, diet, and predators== |
==Behaviour, diet, and predators== |
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===Behaviour=== |
===Behaviour=== |
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This species is mostly diurnal, but may be active at night as well.<ref name="ErZug"/> It is an arboreal snake, but it does commonly go to the ground. In fact, it is equally at home hunting and feeding on prey on the ground or in trees. When it wants to sleep it seeks out tree branches that offer dense cover. It is a very quick, extremely agile, alert, and very aggressive and nervous snake. |
This species is mostly diurnal,<ref name=S&B95/> but may be active at night as well.<ref name="ErZug">{{cite book |last= Ernst|first= Carl H.|last= Zug|first= George R.|title= Snakes in Question: The Smithsonian Answer Book |year= 1996|publisher= Smithsonian Institution Scholarly Press |location= Washington D.C., USA|isbn= 1-56098-648-4}}</ref> It is an arboreal snake, but it does commonly go to the ground. In fact, it is equally at home hunting and feeding on prey on the ground or in trees. When it wants to sleep it seeks out tree branches that offer dense cover. It is a very quick, extremely agile, alert, and very aggressive and nervous snake. When confronted it will quickly attempt to escape (usually up a tree if possible) and avoid any sort of confrontation. If cornered, the Western green mamba is highly dangerous and will show a fearsome display of aggression, loudly hissing and striking repeatedly.<ref name=S&B95/> |
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===Diet=== |
===Diet=== |
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The western green mamba's natural prey consists mainly of [[birds]] and small [[mammal]]s, including [[rodents]] such as [[Mouse|mice]], [[rat]]s, and [[squirrel]]s. Other mammals include [[bat]]s, [[Tree Pangolin|tree pangolins]], and [[shrew]]s.<ref name= |
The western green mamba's natural prey consists mainly of [[birds]] and small [[mammal]]s, including [[rodents]] such as [[Mouse|mice]], [[rat]]s, and [[squirrel]]s. Other mammals include [[bat]]s, [[Tree Pangolin|tree pangolins]], and [[shrew]]s.<ref name="WCH"/> They also feed on [[lizard]]s, [[frog]]s, and bird eggs. This snake actively pursues its prey, striking rapidly and often until the prey succumbs to the venom.<ref name=S&B95/><ref name="Mambas">{{cite book |last= Bargar|first=Sherie|last=Johnson |first=Linda |title= Mamba's |year=1987 |publisher= Rourke Enterprises |location=USA|isbn= 0-86592-960-2}}</ref> |
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===Predators=== |
===Predators=== |
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==Venom== |
==Venom== |
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[[File:Viridis DSC02996.jpg|left|thumb]] |
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The western green mamba's venom is similar to other members of the [[mamba]] (''Dendroaspis'') family, but differs from other mamba's in toxicity or even the mixture of toxins in the venom at times. The venom consists mainly of [[neurotoxin]]s, [[cardiotoxin]]s,<ref name="ErZug"/><ref name= |
The western green mamba's venom is similar to other members of the [[mamba]] (''Dendroaspis'') family, but differs from other mamba's in toxicity or even the mixture of toxins in the venom at times. The venom consists mainly of [[neurotoxin]]s, [[cardiotoxin]]s,<ref name="ErZug"/><ref name=WGMBite/> and fasciculins. The [[subcutaneous injection|SC]] and [[intravenous injection|IV]] {{LD50}} for this species is 0.79 mg/kg and 0.71 mg/kg, respectively (Christensen and Anderson (1967).<ref name="WCH"/> Another experimental IV LD<sub>50</sub> toxicity of 0.5 mg/kg has been reported, with an average wet venom yield of 100 mg.<ref name=S&B95/> Human fatalities as a result of bites from this species are rare due to the fact that this species does not often cross paths with humans, but bites have occurred and many of the recorded bites have been fatal.<ref name=S&B95/> When bitten, symptoms rapidly begin to manifest, usually within the first 15 minutes or less. Common symptoms of a bite from a western green mamba include local pain and swelling, although uncommon, local necrosis can be moderate, [[ataxia]], headache, drowsiness, difficulty breathing, [[vertigo]], hypotension (low blood pressure), diarrhea, dizziness, and paralysis. Left untreated, new and more severe symptoms begin to manifest. All symptoms worsen and the victim eventually dies due to suffocation resulting from paralysis of the respiratory muscles. Depending on the nature and severity of a bite, death can occur in as fast as an hour but usually it takes 2–4 hours before an untreated victim dies.<ref name=WGMBite/><ref name="WCH"/><ref name="Mambas"/> |
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==Taxonomy== |
==Taxonomy== |
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Three very close relatives of the western green mamba ''(Dendroaspis viridis)'' are the [[eastern green mamba]] ''(Dendroaspis angusticeps)'', the [[black mamba]] ''(Dendroaspis polylepis)'', and the [[Jameson's mamba]] ''(Dendroaspis jamesoni)'' which has two subspecies: Jameson's green mamba ''(Dendroaspis jamesoni jamesoni)'' and Jameson's black-tail mamba ''(Dendroaspis jamesoni kaimosea)''.<ref name="Hallowell"/><ref name= |
Three very close relatives of the western green mamba ''(Dendroaspis viridis)'' are the [[eastern green mamba]] ''(Dendroaspis angusticeps)'', the [[black mamba]] ''(Dendroaspis polylepis)'', and the [[Jameson's mamba]] ''(Dendroaspis jamesoni)'' which has two subspecies: Jameson's green mamba ''(Dendroaspis jamesoni jamesoni)'' and Jameson's black-tail mamba ''(Dendroaspis jamesoni kaimosea)''.<ref name="Hallowell"/><ref name="WCH"/> |
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==Gallery== |
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<gallery> |
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<!--Image:Dendroaspis viridisPCCA20051227-1887B.jpg|Western green mamba at Jacksonville Zoo, Jacksonville, Florida, United States. --> |
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Image:Western_Green_Mamba_01.jpg|Western green mamba at Wilmington's Serpentarium. |
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Image:Western_Green_Mamba_02.jpg|Western green mamba at Wilmington's Serpentarium. |
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Image:Western_Green_Mamba_03.jpg|Western green mamba at Wilmington's Serpentarium. |
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Image:Viridis DSC02996.jpg|Western green mamba yellow male, turquoise female |
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Image:Viridis DSC01836.jpg|Western green mamba male |
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</gallery> |
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{{Commons|Dendroaspis viridis}} |
{{Commons|Dendroaspis viridis}} |
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[[Category:Reptiles of Africa]] |
[[Category:Reptiles of Africa]] |
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[[Category:Snakes of Africa]] |
[[Category:Snakes of Africa]] |
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[[Category:Venomous snakes]] |
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Revision as of 13:58, 4 March 2014
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| Species: | D. viridis
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The Western green mamba (Dendroaspis viridis), also known as the West African green mamba or Hallowell's green mamba,[5] is a long, thin and highly venomous snake of the genus Dendroaspis (Mambas).[6] The Western green mamba is a fairly large and predominantly arboreal species, capable of navigating through trees swiftly and gracefully. This species will also descend to ground level where it actively pursues and hunts prey items such as rodents and other small mammals. The Western green mamba is a very alert, nervous and extremely agile snake that lives mainly in the coastal tropical rainforest, thicket, and woodland regions of western Africa.[7] Like all the other mambas, the Western green mamba is a highly venomous elapid species. Its venom is a potent mixture of rapid-acting pre-snaptic and postsynaptic neurotoxins, cardiotoxins and fasciculins. This is not a particularily aggressive snake and conflict with humans is minimal. As a result, bites to people by this species are quite uncommon. Nevertheless, mortality rates are very high as bites attributed to this species have occurred and many of the recorded bites have often been fatal. Rapid progression of severe life-threatening symptoms are hallmarks of mamba bites. Bites with envenomation can be rapidly fatal. Case reports of rapidly fatal outcomes, in as little as 30 minutes, have been recorded for this species.[8]
Etymology
The Western green mammba is classified under the genus Dendroaspis of the family Elapidae. Dendroaspis viridis was first described by the American herpetologist and physician Edward Hallowell in 1844.[3][9] The generic name, Dendroaspis, is derived from Ancient Greek words – Dendro, which means "tree",[10] and aspis (ασπίς) or "asp", which' is understood to mean "shield", but it also designate "cobra" or simply "snake". In old text, aspis or asp was used to refer to Naja haje (in reference with the hood, like a shield).[11] Thus, "Dendroaspis" literally means tree snake, which refers to the arboreal nature of most of the species within the genus. Schlegel used the name Dendroaspis, significant tree cobra. The specific name viridis is of Latin origin and means "green".[12]
Biology
Identification and physical description
The western green mamba is a long and very slender bodied snake with a long tapering tail. The average length of an adult snake of this species is between 1.4 metres (4.6 ft) and 2.1 metres (6.9 ft). Some specimens of this species can grow to maximum lengths of 2.4 metres (7.9 ft).[7] The head is narrow and elongate, with a distinct canthus and slightly distinct from the neck. On rare occasions the neck may be flattened when the snake is aroused, but there is no hood. Eyes are medium in size with round pupils and a yellow brown iris. Dorsal surface body colour is vivid yellowish green to green with anterior margins of the scales yellow. In many specimens the posterior body and tail are yellow. In some specimens dorsal body scales are distinctly bordered with black forming chevron shaped markings. The black interstitial skin is clearly visible especially highlighting individual head scales and scales on the tail. Head dorsum is similar to dorsal surface anterior body colour or slightly darker green. Laterally the head scales, particularly the labials, are distinctly black edged and colouration is usually paler than dorsum or slightly yellowish tinted. When viewed from above the black edging of scales and black interstitial skin result in a plaited appearance. Head venter, throat, ventral and subcaudal surface colour is pale yellowish to yellowish green.[5]
Scalation
The head, body and tail scalation of the western green mamba:[5]
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Distribution and habitat
Geographic range
The western green mamba is native to West Africa can be found in Benin, Cote d'Ivoire ( Ivory Coast ), Gambia, Ghana, Guinea, Guinea-Bissau, Liberia, Senegal, Sierra Leone, and Togo.[5] The species occurs from Gambia and southern Senegal to Benin. It is confined to the humid tropics, with records from Guinea-Bissau, Guinea, Sierra Leone[13] and Togo. In Togo it has a known northern limit to its distribution in Aledjo, but it might occur in forests of the more northerly Kara region [14] Old records from Nigeria are unreliable. It can also be found in the very southern tip of Mali along the border with Côte d’Ivoire, western Cameroon and Gabon.[15]
Habitat
Western green mambas live mainly in the coastal tropical rainforest, thicket, and woodland regions of western Africa. The majority of records from within the continuous forest block, but the Gambia and Guinea-Bissau records are from isolated forests. The species persists in areas where the tree cover has been removed, providing that sufficient hedges and thicket remain. Found in some suitably vegetated suburbs and towns and parklands therein.[7] Western green mambas are snakes of humid forest. This species is largely confined to areas where rainfall exceeds 1,500 millimetres (150 cm).[13] In Togo, however, its range extends into the drier open forests of the north, the Guinean savannas of the west, and the littoral zone.[14]
Conservation status
This species is classified as Least Concern (LC) on the IUCN Red List of Threatened Species (v3.1, 2011). The conservation status of this species was last assessed in July 2012 and published in 2013, and it was classed as such due to a wide distribution, fairly generalist habits, stable population and the lack of major threats.[1]
Behaviour, diet, and predators
Behaviour
This species is mostly diurnal,[7] but may be active at night as well.[16] It is an arboreal snake, but it does commonly go to the ground. In fact, it is equally at home hunting and feeding on prey on the ground or in trees. When it wants to sleep it seeks out tree branches that offer dense cover. It is a very quick, extremely agile, alert, and very aggressive and nervous snake. When confronted it will quickly attempt to escape (usually up a tree if possible) and avoid any sort of confrontation. If cornered, the Western green mamba is highly dangerous and will show a fearsome display of aggression, loudly hissing and striking repeatedly.[7]
Diet
The western green mamba's natural prey consists mainly of birds and small mammals, including rodents such as mice, rats, and squirrels. Other mammals include bats, tree pangolins, and shrews.[5] They also feed on lizards, frogs, and bird eggs. This snake actively pursues its prey, striking rapidly and often until the prey succumbs to the venom.[7][17]
Predators
The western green mamba has no natural predators, but humans and birds of prey are this snake's main threat.[6][17]
Venom
The western green mamba's venom is similar to other members of the mamba (Dendroaspis) family, but differs from other mamba's in toxicity or even the mixture of toxins in the venom at times. The venom consists mainly of neurotoxins, cardiotoxins,[16][8] and fasciculins. The SC and IV LD50 for this species is 0.79 mg/kg and 0.71 mg/kg, respectively (Christensen and Anderson (1967).[5] Another experimental IV LD50 toxicity of 0.5 mg/kg has been reported, with an average wet venom yield of 100 mg.[7] Human fatalities as a result of bites from this species are rare due to the fact that this species does not often cross paths with humans, but bites have occurred and many of the recorded bites have been fatal.[7] When bitten, symptoms rapidly begin to manifest, usually within the first 15 minutes or less. Common symptoms of a bite from a western green mamba include local pain and swelling, although uncommon, local necrosis can be moderate, ataxia, headache, drowsiness, difficulty breathing, vertigo, hypotension (low blood pressure), diarrhea, dizziness, and paralysis. Left untreated, new and more severe symptoms begin to manifest. All symptoms worsen and the victim eventually dies due to suffocation resulting from paralysis of the respiratory muscles. Depending on the nature and severity of a bite, death can occur in as fast as an hour but usually it takes 2–4 hours before an untreated victim dies.[8][5][17]
Taxonomy
Three very close relatives of the western green mamba (Dendroaspis viridis) are the eastern green mamba (Dendroaspis angusticeps), the black mamba (Dendroaspis polylepis), and the Jameson's mamba (Dendroaspis jamesoni) which has two subspecies: Jameson's green mamba (Dendroaspis jamesoni jamesoni) and Jameson's black-tail mamba (Dendroaspis jamesoni kaimosea).[6][5]
References
- ^ a b Template:IUCN
- ^ "Dendroaspis". Integrated Taxonomic Information System. Retrieved 4 March 2014.
- ^ a b "Dendroaspis viridis". Integrated Taxonomic Information System. Retrieved 4 March 2014.
- ^ Boulenger, G.A. 1896. Catalogue of the Snakes in the British Museum (Natural History), Volume III. London. p. 435.
- ^ a b c d e f g h "Dendroaspis viridis". Clinical Toxinology Resource. University of Adelaide. Retrieved 4 March 2014.
- ^ a b c Hallowell, E. (1844). Description of new species of African reptiles (PDF). Vol. 2. Philadelphia, USA: Proceedings of the National Academy of Sciences (Stanford University's Highwire Press). pp. 169–172. ISSN 0097-3157. LCCN //r24 12030019 //r24. OCLC 1382862.
{{cite book}}: Check|lccn=value (help) - ^ a b c d e f g h Spawls, S., Branch, B. (1995). The Dangerous Snakes of Africa. Blandford. pp. 51–52. ISBN 978-0-88359-029-4.
{{cite book}}: CS1 maint: multiple names: authors list (link) - ^ a b c "Immediate First Aid for bites by Western Green Mamba (Dendroaspis viridis)". Toxicology. University of California, San Diego. Retrieved 4 March 2014.
- ^ Hallowell, E. (December, 1844). "Description of new species of African reptiles" (PDF). Proceedings of the Academy of Natural Sciences of Philadelphia. v. 2 (1844-1845): 169–172. Retrieved 4 March 2014.
{{cite journal}}: Check date values in:|date=(help) - ^ "dendro-". Collins English Dictionary - Complete & Unabridged 10th Edition. HarperCollins Publishers. Retrieved 4 March 2014.
- ^ "aspis, asp". Dictionary.com Unabridged. Random House. Retrieved 4 March 2014.
- ^ "Definition of "viridis"". Numen - The Latin Lexicon. http://latinlexicon.org/index.php. Retrieved 4 March 2014.
{{cite web}}: External link in|publisher= - ^ a b Trape, JF., Mané, Y. (18 October 2006). Guide des serpents d'Afrique occidentale : Savane et désert. IRD Orstom. ISBN 978-2-70-991600-4.
{{cite book}}: CS1 maint: multiple names: authors list (link) - ^ a b Segniagbeto, GH. (September 2011). "The snake fauna of Togo: systematics, distribution and biogeography, with remarks on selected taxonomic problems". Zoosystema. 33 (3): 325–360. doi:10.5252/z2011n3a4.
{{cite journal}}:|access-date=requires|url=(help); Unknown parameter|coauthors=ignored (|author=suggested) (help) - ^ O'Shea, M. (2005). Venomous Snakes of the World. United Kingdom: New Holland Publishers. ISBN 0-691-12436-1.
- ^ a b Zug, George R. (1996). Snakes in Question: The Smithsonian Answer Book. Washington D.C., USA: Smithsonian Institution Scholarly Press. ISBN 1-56098-648-4.
- ^ a b c Johnson, Linda (1987). Mamba's. USA: Rourke Enterprises. ISBN 0-86592-960-2.
External links
- Bushdrums.com - Green Mamba Video filmed in Gabon