Black Mamba (Dendroaspis polylepis), is an elapid snake and is one of Africa's most dangerous and feared snakes. It has a wide range of known locations throughout Africa. The black mamba is found in Ethiopia, Kenya, Botswana, Uganda, Zambia, Zimbabwe, Angola, Namibia, Malawi, Mozambique, Swaziland, South Africa and the Congo. They inhabit a wide variety of areas that include open savannahs, open woodlands, and rocky outcrops.[1] It is also known for being very aggressive when threatened and will not hesitate to strike with deadly precision.
The black mamba is the longest venomous snake in Africa and the second longest venomous snake in the world. Adult black mambas have an average length of 2.5 meters (8.2 ft) and a maximum length of 4.3 meters (14 ft).[2] Of the venomous snakes of the world, only the King Cobra is longer. [3] Like all other extant reptiles, the black mamba relies on external heat to regulate the temperature of its body.[1] The name "black mamba" is somewhat confusing because it contradicts the snake's actual color. Its body is not black at all; the name is given to it because of its inky black mouth. Normally, mambas have a dark olive, olive green, grey brown, or metal color. Some of them have a light band around their body. As mambas get older, their skin begins to darken.[4] The black mamba is reputed to be the fastest moving snake in the world, and has been claimed to move at up to 19.5 km/h (12 mph).[2]
Diet
Black mambas are diurnal snakes that hunt prey actively during the day or night.[2] Warm-blooded prey, such as rodents, ground squirrels, and other small mammals, are the mamba's main source of food. When hunting small animals, the black mamba delivers one or two deadly bites and backs off, waiting for the neurotoxin in its venom to paralyze the prey.[4] When killing a bird, however, the black mamba will cling to its prey, preventing its departure. Black mambas have also been said to have eaten other reptiles and snakes but there is little documentation to support it.[2] "After ingestion, powerful acids digest the prey, sometimes within 7 to 10 hours."[5]
Behavior
When warding off a bigger threat or feeling very threatened, the black mamba usually delivers multiple strikes, injecting its potent neuro- and cardiotoxin with each strike, often attacking the body or head, unlike most other snakes.A single bite from a black mamba injects enough venom to kill anywhere from 20–25 grown men, easily killing one unless the appropriate anti-venom is administered in time. When cornered, it will readily attack. When in the striking position, the mamba flattens its neck, hisses very loudly and displays its inky black mouth and fangs. It can rear up around one-third of its body from the ground, which allows it to reach heights of approximately four feet. However, the black mamba would rather attempt to avoid a confrontation with humans.[2][1]
If left undisturbed, black mambas tend to live for long periods of time in their lairs, which are often vacated insect mounds or hollow trees. Although they are not considered to be arboreal, they can sometimes be found in trees. They also seem to have permanent basking spots which are returned to daily. Typically, when a black mamba senses danger, it will quickly slither away to the nearest hiding spot.[4]
Black mambas show little difference from the common methods of communication and perception found in all other snakes. They use their eyesight to detect motion. Sudden movements will cause them to strike. The tongue of the mamba is extended from the mouth to collect and analyze air particles which are then deposited in the vomeronasal organ on the roof of the mouth. This organ acts as a chemosensory organ. These snakes have no external ears, but are quite skilled at detecting vibrations from the ground. Just like other snakes, they will display aggression with a set of signals, warning the possibility of attack if threatened.[5]
Venom
Black mambas are among the most venomous snakes in Africa, with a LD50 of 0.25 mg/kg. A bite from a black mamba delivers about 100–120 mg of venom on average; however it can deliver up to 400 mg. About 10-15 mg of its venom is enough to kill an adult. The initial symptom of the bite is local pain in the bite area, although not as severe as in a bite from snakes with cytotoxins. The victim soon experiences a tingling sensation in the mouth and extremities, dizziness, erratic heartbeat, ptosis, diplopia (double vision), dysphagia, tunnel vision, ophthalmoparesis, severe confusion, dysarthria, fever, diaphoresis (excessive perspiration), excessive salivation (including foaming of the mouth and nose), and pronounced ataxia (lack of muscle control). If the victim does not receive medical attention, symptoms rapidly progress to severe abdominal pain, nausea and vomiting, lymphadenopathy, severe dyspnea (shortness of breath), epistaxis, pallor, shock, nephrotoxicity, cardiotoxicity, and paralysis. Eventually, the victim experiences convulsions, cardiac arrest, respiratory arrest, coma, and then death. Without antivenom, the mortality rate nears 100%, the highest among venomous snakes.[6][7] Depending on the nature of the bite, death can result at any time between 15 minutes and 3 hours. On average, however, death usually occurs 30 to 60 minutes after envenomation.[8] Factors associated with the nature of the bite include penetration of one or both fangs, amount of venom injected, location of the bite, and proximity to major blood vessels. The health of the snake and the interval since it last used its venom mechanism may also be factors. The health, size, age, and psychological state of the individual bitten is also a determining factor.
Lifestyle
Black mambas live primarily in the grasslands of Africa and, though not considered an arboreal species, can live in bushes and small trees and also in houses. Their diet consists mainly of small birds and rodents and, despite the negative reputation, they play a crucial role in regulating pests. A black mamba can live up to 12 years.
Breeding
Black mambas breed starting in the spring and early summer. Sometimes, the males must travel long distances to look for females. Males will locate the right female by following a scent trail. When the male finds his mate, he will thoroughly inspect her by flicking his tongue across her entire body. Males are equipped with hemipenes, or a dual set of penises. Copulation is prolonged.[5] When breeding takes place, two mambas twist their bodies together and begin mating which can last up to 2 whole days. After mating, male mambas have no interaction with the females or their offspring. The females too have no attachment to their young and will abandon them after laying their eggs. [1] Mating season also introduces fighting among the males for other females. This act involves the intertwining the bodies of two males with their heads up to 1m off the ground. This fighting behavior can easily be mistaken for mating.[5] After mating, each snake returns to its own burrow. Females wait approximately 55 days before laying between 10 and 25 eggs, that will hatch in 80-90 days. When females lay their eggs, they try to find an area with decaying vegetation. Since the vegetation is decaying, it gives off heat, which helps to warm the eggs and speed up the hatching process. It also serves to hide the smell of the eggs which keeps predators away. Each egg shell allows water and oxygen to reach the developing embryos.[1] The yolk of the egg is absorbed into the body and can supply the young with adequate nutrients for quite some time. Baby mambas break through the egg shell with an egg tooth. A newly hatched black mamba is approximately 51cm long and has a grayish-green color. They have fully developed venom glands from the start and are dangerous within just minutes after birth.[5] There is no size discrepancy between a male or female mamba. Once they have hatched, they are immediately independent and can catch prey the size of a small rat. In their first year of life, they reach 2m in length. The only major problem facing the young baby snakes are mongooses. [1]
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