Mamba

The three green species of mambas are arboreal, whereas the black mamba is largely terrestrial. All four species are active diurnal hunters, preying on birds, lizards, and small mammals. At nightfall some species, especially the terrestrial black mamba, shelter in a lair. A mamba may retain the same lair for years. Resembling a cobra, the threat display of a mamba includes rearing, opening the mouth and hissing. The black mamba's mouth is black within, which renders the threat more conspicuous. A rearing mamba has a narrower yet longer hood and tends to lean well forward, instead of standing erect as a cobra does.

Stories of black mambas that chase and attack humans are common, but they generally avoid contact with humans.{{cite book|last=O'Shea|first=Mark|title=VENOMOUS SNAKES OF THE WORLD|year=2005|publisher=US and Canada: Princeton University Press; Europe: New Holland (UK) Ltd|location= multiple places|isbn=978-0-691-15023-9|pages=78–79|quote=...in common with other snakes they prefer to avoid contact;...Of the three species of green mambas...;...from 1957 to 1963...including all seven black mamba bites - a 100 per cent fatality rate}} The black mamba (Dendroaspis polylepis) is a highly venomous snake native to parts of sub-Saharan Africa. Black mambas are fast-moving, nervous snakes that strike when threatened. According to findings by Branch (2016), their venom has neurotoxins and cardiotoxins that rapidly induce symptoms of dizziness, extreme fatigue, vision problems, foaming at the mouth, paralysis, convulsions, and eventual death from respiratory or cardiac failure if untreated. Although black mamba venom is highly toxic, antivenom is available and can treat envenomation promptly.

Most apparent cases of pursuit are likely examples of witnesses mistaking the snake's attempt to retreat to its lair when a human happens to be in the way.{{cite book|title= The new encyclopedia of Reptiles (Serpent)|year=2002|publisher=Time Book Ltd}} The black mamba usually uses its speed to escape from threats, and humans are their main predators, rather than prey.

All mambas have medically significant venom, with dendrotoxins, short chain alpha-neurotoxins, cardiotoxins and fasciculins.{{cite web|url=http://cogs.csustan.edu/~tom/bioinfo/groupwork/cobra/cobra-venom.ppt|title=Neurotoxins in Snake Venom|access-date=2019-12-26}}{{cite journal |vauthors=van Aswegen G, van Rooyen JM, Fourie C, Oberholzer G |title=Putative cardiotoxicity of the venoms of three mamba species. |journal= Wilderness & Environmental Medicine|volume=7|issue=2 |date=May 1996 |pmid=11990104 |pages=115–21 |doi=10.1580/1080-6032(1996)007[0115:PCOTVO]2.3.CO;2|doi-access=free }} All mambas are classified as snakes of medical importance by the World Health Organization.{{cite web |last1=WHO Expert Committee on Biological Standardization |title=Guidelines for the production, control and regulation of snake antivenom immunoglobulins |url=https://www.who.int/bloodproducts/AntivenomGLrevWHO_TRS_1004_web_Annex_5.pdf |access-date=1 January 2019 | pages=224–226 | work= WHO Technical Report Series, No. 964}}{{efn|1=Snakes of medical importance include those with highly dangerous venom resulting in high rates of morbidity and mortality, or those that are common agents in snakebite.}}

There are multiple components in dendrotoxins with different targets:

• Dendrotoxin 1, which inhibits the K⁺ channels at the pre and post-synaptic level in the intestinal smooth muscle. It also inhibits Ca²⁺-sensitive K⁺ channels from rat skeletal muscle‚ incorporated into planar bilayers (Kd = 90 nM in 50 mM KCl).{{cite journal |vauthors=Newitt RA, Houamed KM, Rehm H, Tempel BL |title=[Potassium channels and epilepsy: evidence that the epileptogenic toxin, dendrotoxin, binds to potassium channel proteins.] |volume=4 |pages=263–73|year=1991 |pmid=1815606 |journal=Epilepsy Research Supplement}})
• Dendrotoxin 3, which inhibits acetylcholine M4 receptors.{{cite book |author=Rang, H. P. |title=Pharmacology |publisher=Churchill Livingstone |location=Edinburgh |year=2003 |pages= 139 |isbn=0-443-07145-4 }}
• Dendrotoxin 7, commonly referred to as muscarinic toxin 7 (MT7) inhibits acetylcholine M1 receptors.
• Dendrotoxin K, structurally homologous to Kunitz-type proteinase inhibitors{{cite journal |vauthors=Berndt KD, Güntert P, Wüthrich K |title=[Nuclear magnetic resonance solution structure of dendrotoxin K from the venom of Dendroaspis polylepis polylepis.] |volume=234 |issue=3 |pages= 735–50|date=5 December 1993 |pmid=8254670 |journal=Journal of Molecular Biology |doi=10.1006/jmbi.1993.1623}} with activity as a selective blocker of voltage-gated potassium channels{{cite journal |vauthors=Harvey AL, Robertson B |title=Dendrotoxins: structure-activity relationships and effects on potassium ion channels.|journal=Curr. Med. Chem. |year=2004 |volume=11|issue=23|pages=3065–72 |pmid=15579000 |doi=10.2174/0929867043363820}}

Toxicity alone does not determine severity of envenomation; other factors include the snake's temperament, venom yields, proximity of wounds to the CNS and depth of punctures.{{cite book |author1=Warrell, DA |author1-link=Clinical Toxicology of Snakebite in Africa and the Middle East |editor1-last=Meier |editor1-first=J |editor2-last=White |editor2-first=J |title=Handbook of Clinical Toxicology of Animal Venoms and Poisons |date=1995 |publisher=CRC Press |location=Boca Raton |isbn=9781351443142 |pages=433–492 |edition=1 |url=https://www.routledge.com/Handbook-of-Clinical-Toxicology-of-Animal-Venoms-and-Poisons/White-Meier/p/book/9780849344893}} Bites by all members of this genus are capable of causing rapid onsets of symptoms, but it is the black mamba whose bite has the worst prognosis, possibly as a result of its more terrestrial nature (having more potential for human contact), high defensiveness (having a higher possibility to deliver fatal bites instead of dry bites), large size (giving it a higher strike position proximal to the victim's brain), and higher average venom yields and potential toxicity (based on experimental results).{{cite web |url=http://www.seanthomas.net/oldsite/ld50tot.html |title=LD50 (Archived) |author=Séan Thomas |author2=Eugene Griessel – Dec 1999 |name-list-style=amp |url-status=dead |archive-url=https://web.archive.org/web/20120201062634/http://www.seanthomas.net/oldsite/ld50tot.html |archive-date=1 February 2012}}{{cite journal |last1=Branch |first1=W |title=The venomous snakes of Southern Africa Part 2. Elapidae and Hydrophidae |journal=The Snake |date=January 1979 |volume=11 |issue=2 |pages=199–225 |url=https://www.researchgate.net/publication/290484689 |access-date=1 July 2021}} A lethality rate of near 100% for untreated black mamba bites has been circulating between various sources, which is probably based on a single medical record made in a single district between 1957 and 1963 when specific antivenom had yet to be introduced. Seven out of seven victims of this species who received non-specific polyvalent antivenom, that had no effect on the species' toxins, succumbed to its bites.{{cite book|last=O'Shea|first=Mark|title=VENOMOUS SNAKES OF THE WORLD|year=2005|publisher=US and Canada: Princeton University Press; Europe: New Holland (UK) Ltd|location= multiple places|isbn=978-0-691-15023-9|pages=78–79|quote=...in common with other snakes they prefer to avoid contact;...Of the three species of green mambas...;...from 1957 to 1963...including all seven black mamba bites - a 100 per cent fatality rate}} However, another snakebite survey in South Africa reported a death rate of approximately 43% among those who received ineffective treatments (15 fatal cases out of 35 patients). A mamba-specific antivenom was introduced in 1962, followed by a fully polyvalent antivenom in 1971; over this period, 5 out of 38 people in South Africa bitten by black mambas who received the antivenom died, according to the same report.{{cite journal |last1=Christensen |first1=P.A. |title=Snakebite and the use of antivenom in southern Africa |journal=South African Medical Journal |date=1981 |volume=59 |issue=26 |pages=934–938 |pmid=7244896 |url=http://archive.samj.org.za/1981%20VOL%20LIX%20Jan-Jun/Articles/06%20June/3.6%20SNAKEBITE%20AND%20THE%20USE%20OF%20ANTIVENOM%20IN%20SOUTERN%20AFRICA,%20P.A.Christensen.pdf}} Since then, the number has significantly dropped with the widespread use of specific antivenom.{{cite journal|last1=Nhachi|first1=Charles FB|last2=Kasilo| first2=Ossy M.|title=Snake poisoning in rural Zimbabwe – A prospective study |journal=Journal of Applied Toxicology |year=1994|volume=14|issue=3|pages=191–193|doi=10.1002/jat.2550140308|pmid=8083480|s2cid=40171925}}

Despite their fearsome reputation and often exaggerated notoriety, mamba envenomation occurs far less frequently than some other snakes', for instance the puff adder. Besides proximity to residences, behaviour of a given species is also a critical aspect when it comes to snakebite morbidities. Mambas are agile, usually fleeing from any confrontation with unambiguous threat display which allows early recognition of the serpent, avoiding escalation in tension.

Dendroaspis, is derived from Ancient Greek déndron (δένδρον), meaning "tree",{{cite web|title=dendro-|url=http://dictionary.reference.com/browse/dendro-|work=Collins English Dictionary - Complete & Unabridged 10th Edition|publisher=HarperCollins Publishers|access-date=4 March 2014}} and aspis (ασπίς), which is understood to mean "shield",{{cite web|url=http://www.collinsdictionary.com/dictionary/english/aspis|title=Definition of "aspis" - Collins English Dictionary|work=collinsdictionary.com|access-date=15 February 2015}} but also denotes "cobra" or simply "snake", in particular "snake with hood (shield)". Via Latin aspis, it is the source of the English word "asp". In ancient texts, aspis or asp often referred to the Egyptian cobra (Naja haje), in reference to its shield-like hood.{{cite web|title=aspis, asp|url=http://dictionary.reference.com/browse/asp|work=Dictionary.com Unabridged|publisher=Random House |access-date=4 March 2014}} The genus was first described by the German naturalist Hermann Schlegel in 1848,{{ITIS|id=700211|taxon=Dendroaspis|access-date=9 December 2013}} with Elaps jamesonii as the type species. It was misspelt as Dendraspis by Dumeril in 1856, and generally uncorrected by subsequent authors. In 1936, Dutch herpetologist Leo Brongersma pointed out that the correct spelling was Dendroaspis but added that the name was invalid as Fitzinger had coined Dendraspis in 1843 for the king cobra and hence had priority.{{cite journal |last1=Brongersma |first1=Leo Daniel |title=Herpetological note XIII |journal=Zoo. Mededeel. |date=1936 |volume=19 |page=135}} However, in 1962 German herpetologist Robert Mertens proposed that the 1843 description of Dendraspis by Fitzinger be suppressed due to its similarity to Dendroaspis, and the confusion it would cause by its use.{{cite journal |last1=Mertens |first1=Robert |title=Dendraspis Fitzinger, 1843 (Reptilia, Serpentes); Proposed Suppression under the Plenary Powers. Z.N. (S.) 1500 |journal=Bulletin of Zoological Nomenclature |date=1962 |volume=19 |pages=189–190 |url=https://digitalgems.nus.edu.sg/shared/colls/blsea/files/BulZooN_v19_part03-59635af928ac4.pdf}}

Black mambas live in the savannas and rocky hills of southern and eastern Africa. They are Africa's longest venomous snake, reaching up to 14 feet in length, although 8.2 feet is more the average. They are also among the fastest snakes in the world, slithering at speeds of up to 12.5 miles per hour.

* Including the nominate subspecies.

^T Type species.

A 2018 analysis of the venom of the mambas, as well as a 2016 genetic analysis, found the following cladogram representative of the relationship between the species.{{cite journal|last1=Ainsworth|first1=Stuart|last2=Petras|first2=Daniel|last3=Engmark|first3=Mikael|last4=Süssmuth|first4=Roderich D.|last5=Whiteley|first5=Gareth|last6=Albulescu|first6=Laura-Oana|last7=Kazandjian|first7=Taline D.|last8=Wagstaff|first8=Simon C.|last9=Rowley|first9=Paul|last10=Wüster|first10=Wolfgang|last11=Dorrestein|first11=Pieter C.|date=2018|title=The medical threat of mamba envenoming in sub-Saharan Africa revealed by genus-wide analysis of venom composition, toxicity and antivenomics profiling of available antivenoms|url=https://archive.lstmed.ac.uk/7572/1/J_Proteomics_The%20medical%20threat%20of%20mamba.docx|journal=Journal of Proteomics|volume=172|pages=173–189|doi=10.1016/j.jprot.2017.08.016|pmid=28843532|first12=Ana Silvia|last12=Arias|first16=Juan J.|last15=Casewell|first15=Nicholas R.|last14=Harrison|first14=Robert A.|last13=Gutiérrez|first13=José M.|last16=Calvete|s2cid=217018550 |hdl=10261/279110|hdl-access=free}}{{Cite journal|last1=Figueroa|first1=A.|last2=McKelvy|first2=A. D.|last3=Grismer|first3=L. L.|last4=Bell|first4=C. D.|last5=Lailvaux|first5=S. P.|date=2016|title=A species-level phylogeny of extant snakes with description of a new colubrid subfamily and genus|journal=PLOS ONE|volume=11|issue=9|pages=e0161070|bibcode=2016PLoSO..1161070F|doi=10.1371/journal.pone.0161070|pmc=5014348|pmid=27603205|doi-access=free}}

{{clade|{{clade

|1={{clade

|1=Ophiophagus hannah

}}

|2={{clade

|1={{clade

|1={{clade

|1=D. j. jamesoni

|2=D. j. kaimosae

}}

|2= D. viridis

}}

|2={{clade

|1=D. angusticeps

|2=D. polylepis

}}

}}

}}}}

{{Notelist|30em}}

{{Reflist|30em}}

{{Commons category|Dendroaspis}}

{{wikispecies|Dendroaspis}}

• {{Cite journal |last=H.M. |date=January 1978 |title=Snake venom toxins. The amino acid sequence of a short-toxin homologue from Dendroaspis polylepis polylepis (black mamba) venom |url=http://dx.doi.org/10.1016/0041-0101(78)90166-6 |journal=Toxicon |volume=16 |issue=4 |pages=407–408 |doi=10.1016/0041-0101(78)90166-6 |issn=0041-0101|url-access=subscription }}

{{Muscarinic acetylcholine receptor modulators}}

{{Taxonbar|from=Q194425}}

{{Authority control}}

Category:Muscarinic antagonists

Category:Taxa named by Hermann Schlegel