Jumat, 18 April 2008

Black Mamba


Black mambas is dangerous and feared snakes in africa. They have average size being between 2.4 to 3 metres (7.8 - 9.8 foot). According to some reports they may grow on exception to 4.5 metres (14.7 feet). Black mambas belong to the genus, Dendroaspis. Nothing is truer when you are standing in front of big black mamba hissing loudly, mouth gaping, striking rapidly in your direction. But are all the frightening stories about black mambas true? I don’t think so. On the African continent many myths are told about these wonderful creatures. Stories abound about black mambas chasing people for miles, attacking when they notice you and visiting houses to kill every single person inside. All are exaggerations. Black mambas are not as fierce as people describe them. In captivity black mambas are docile and appreciative animals that show a fantastic and active behaviour when housed in a big enclosure the right way.Black mambas that reach this size are obviously rare and verifiable data is actually hard to track down.


The name "black mamba" is somewhat confusing as this animal is not black at all. The common name is given to the snake because the mouth is inky black on the inside. Most mambas have a dark olive, olive green, greyish brown or metal grey colour. Some of them will show a light banding around their body. Slightly speckled mambas are also not uncommon. Juvenile black mambas are light grey or olive in colour but will darken when older.
Black mambas are widespread over the African continent and occur from Somalia to South Africa. In the past black mambas were recognized in 2 subspecies: Dendroaspis polylepis polylepis and Dendroaspis polylepis antinorii. But research proved antinorii was an invalid subspecies. Venom research has shown us however, that there can be differences in venom composition in black mambas from different localities.


Black mambas are diurnal snakes that hunt prey actively. They live in a permanent lair which they will use for a long time if not disturbed, and also seem to have permanent basking spots which they will return to daily. Black mambas often live in termite mounds and hollow trees, but even when they are not supposed to be arboreal, they can sometimes be found in trees. Typically, when black mambas sense danger, they will slide away to the nearest hiding place, and are capable of doing this at 20 km/h, which makes the black mamba one of the fastest snakes in the world. Black mambas feed mainly on warm-blooded prey such as rodents, ground squirrels, hyraxes and other small mammals. Birds are occasionally taken. Black mambas’ eating reptiles and other snakes is quite rare and there is little documentation to substantiate it.


Black mambas usually bite their prey once or twice and then allow it go off to die before attempting to eat. They may however, bite and hold when eating birds. Their venom is very potent and is mainly based on neurotoxins that are absorbed quickly by the prey. The venom will cause a blockade at the neuromuscular junction which blocks every signal from the brain passing through the nervous system to the muscles which causes systemic paralysis. The prey will die from suffocation due to paralysis of the muscles of respiration.


Even though venom composition varies in black mambas from different localities, there is a good polyvalent antivenom produced by SAIMR (South African Institute of Medical Research) that effectively covers them all. Bites from black mambas to humans are rare, but are seriously life threatening when they occur. A good first aid treatment rapidly enacted is very important. We apply a pressure immobilization bandage as described by Prof. Struan Sutherland. During transport to the hospital, respiratory support for the bitten patient is very important. This can be either mouth to mouth, mouth to mask, or a bag-valve-mask device used by medical personnel. With good pre-hospital first aid and in-hospital antivenom treatment, 99% of victims survive without any complications. Reversal of symptoms is generally quite rapid with early antivenom administration.

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