Mamba

For other uses, see Mamba (disambiguation).

Dendroaspis
Black Mamba
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Subphylum:	Vertebrata
Class:	Reptilia
Order:	Squamata
Suborder:	Serpentes
Family:	Elapidae
Genus:	Dendroaspis Schlegel, 1848[1][2]
Species
Dendroaspis angusticeps Dendroaspis jamesoni Dendroaspis polylepis Dendroaspis viridis
black - black mamba green - eastern green orange - western green

Mambas, of the genus Dendroaspis (literally "tree snake"), are a group of highly venomous, fast-moving land-dwelling snakes of Africa. They belong to the family of Elapidae which includes cobras, coral snakes, taipans, brown snakes, tiger snakes death adders, kraits and, debatably, sea snakes (although sea snakes are now classed as Hydrophiidae). Mambas are feared throughout their ranges in Africa, especially the Black mamba. In Africa, there are many legends and stories describing these snakes.

Behavior

Captive Black-tailed Jameson's mamba (D. j. kaimosae)

Most of the members of this genus (for example green mambas) are arboreal. However, the black mamba is terrestrial. They are diurnal: during the day, they actively hunt their prey of small mammals, birds, and lizards, and return to the same lair nightly.

Mambas are related to the cobras (Elapidae); their threat display, when they stretch a slightly smaller 'hood' while gaping their mouth, is similar.

Many people believe that the black mamba will chase and attack humans. However, this is probably misunderstood because of the speed with which this species can move.^[3] The black mamba usually uses its speed to escape from threats. Humans are actually their main predators, rather than their prey; mambas generally avoid contact with humans.

Venom

All Mambas are highly venomous. Their venoms consist mostly of neurotoxins (known as dendrotoxins). Besides the neurotoxins, they also carry cardiotoxins^[4][5] and fasciculins. Other components may include calcicludine, which is a known component of the Eastern green mamba's venom and calciseptine, which is a component of Black mamba venom. Toxicity of individual specimens within the same species and subspecies can vary greatly based on several factors, including geographical region. Even the weather and altitude can influence toxicity (Ernst and Zug et al. 1996). A bite can be fatal to humans without access to proper first aid and subsequent antivenom treatment, as it shuts down the lungs and heart. The Western green mamba (D. viridis), Eastern green mamba (D. angusticeps), and Jameson's mamba (D. jamesoni) possess venom similar in composition and effects to that of the black mamba's (D. polylepis). However, their venoms are less toxic (based upon LD₅₀ studies), their temperaments are generally not as aggressive or as explosive when provoked, and none of the three inject as much venom as the black mamba, their bites are materially less dangerous.

Prior to the availability of antivenom, envenomations by members of this genus carried a high fatality rate. An untreated black mamba bite has a mortality rate of 100%.^[6][7][8][9], but presently, fatalities have become much rarer due to wide availability of antivenom.

Mamba toxins

Mamba toxin (or dendrotoxin) consists of several components, with different targets. Examples are:

• 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).^[10])
• Dendrotoxin 3, which inhibits acetylcholine M4 receptors. ^[11]
• Dendrotoxin 7, commonly referred to as muscarinic toxin 7 (MT7) inhibits acetylcholine M1 receptors.^[11]
• Dendrotoxin K, a selective blocker of voltage-gated potassium channels.^[12]

Species

Species[13]	Authority[13]	Subsp.*[13]	Common name	Geographic range
Dendroaspis angusticeps	(Smith, 1849)	0	Eastern green mamba	Found in Kenya, Tanzania, Malawi, Mozambique, Zimbabwe, Swaziland, Namibia, western South Africa, Democratic Republic of the Congo, South Sudan, Sudan, Niger, Central African Republic, Chad
Dendroaspis jamesoni	(Traill, 1843)	2	Jameson's mamba	Found in Central Africa in Sudan, South Sudan, Gabon, Angola, Zambia, Republic of the Congo, Cameroon, Nigeria, Kenya, Uganda, Rwanda, Central African Republic, Benin, Ghana
Dendroaspis polylepis	(Günther, 1864	0	Black mamba	Found in eastern Africa and southern Africa in northeast Democratic Republic of the Congo, southwestern Sudan to Ethiopia, Eritrea, Somalia, Kenya, eastern Uganda, Tanzania, southwards to Mozambique, Swaziland, Malawi, Zambia, Zimbabwe, Lesotho, Rwanda, Djibouti and Botswana to KwaZulu-Natal in South Africa, and Namibia; then northeasterly through Angola to the southeastern part of the Democratic Republic of Congo
Dendroaspis viridis	(Hallowell, 1844)	0	Western green mamba	Found only in western Africa in southern Senegal, Gambia, Guinea-Bissau, Guinea, Sierra Leone, Liberia, Côte d’Ivoire, Ghana, Togo, Benin, and southwest Nigeria

* Including the nominate subspecies.

References

1. ^ www.dahmstierleben.de
2. ^ Wikispecies
3. ^ The new encyclopedia of Reptiles (Serpent). Time Book Ltd. 2002. 
4. ^ van Aswegen G, van Rooyen JM, Fourie C, Oberholzer G. (May 1996). "Putative cardiotoxicity of the venoms of three mamba species.". Journal of Wilderness and Environmental Medicine 7 (2). PMID 11990104. http://www.ncbi.nlm.nih.gov/pubmed/11990104. 
5. ^ Toxipedia (Black Mamba)
6. ^ Mortality Rate
7. ^ Nature-Black Mamba
8. ^ Black Mamba Intro
9. ^ Davidson, Terence. "IMMEDIATE FIRST AID". University of California, San Diego. http://drdavidson.ucsd.edu/portals/0/snake/dendroa3.htm. Retrieved 2011-09-22. 
10. ^ Newitt RA, Houamed KM, Rehm H, Tempel BL. (1991). "[Potassium channels and epilepsy: evidence that the epileptogenic toxin, dendrotoxin, binds to potassium channel proteins.]". Epilepsy Research Supplement 4: 263-73.. PMID 1815606. 
11. ^ ^{a b} Rang, H. P. (2003). Pharamacology. Edinburgh: Churchill Livingstone. pp. 139. ISBN 0-443-07145-4. 
12. ^ Berndt KD, Güntert P, Wüthrich K. (5 December 1993). "[Nuclear magnetic resonance solution structure of dendrotoxin K from the venom of Dendroaspis polylepis polylepis.]". Journal of Molecular Biology 234 (3): 735-50. PMID 8254670. 
13. ^ ^{a b c} ITIS

External links

• Animal Planet
• Cobras