Black mambas are common in sub-Saharan areas of south and east Africa. They can be found as far north as Eritrea, through South Africa, and as far west as Namibia. Though they are not common in western Africa, there have been individual sightings. These sightings may indicate improper documentation, remaining populations from what was once a larger range, or new populations, indicating a growing range. No information was available on introduced range of this species.
Biogeographic Regions: ethiopian (Native )
- Spawls, S., B. Branch. 1995. The Dangerous Snakes of Africa. London: Blandford.
Distribution: Angola, Botswana, Burkina Faso, Central African Republic, Eritrea, Senegal, Guinea, Guinea-Bissau, Mali, Cameroon (Adamaoua [HR 35: 191]), Ethiopia, Ivory Coast, Kenya, Malawi, Mozambique, Namibia, Republic of South Africa, Somalia, Swaziland, Tanzania, Uganda, N/S Democratic Republic of the Congo (Zaire), Zambia, Zimbabwe antinori: Somalia, Ethiopia, NE Uganda, N Kenya;
Type locality: Ansaba = Anseba, Eritrea, Ethiopia.
Type locality: Zambezi River, Mozambique.
Contrary to their common name, black mambas are not actually black. Dendroaspis polylepis can be olive, brownish, gray, or sometimes khaki in color. Young snakes are lighter in color, appearing gray or olive green, but are not light enough to be confused with green mambas (Dendroaspis angusticeps). Their underbody is cream-colored, sometimes blended with green or yellow. Dark spots or blotches may speckle the back half of the body and some individuals have alternating dark and light scales near the posterior, giving the impression of lateral bars. The inside of the mouth is a dark blue to “inky” black color. The eyes are dark brown to black, with a silvery-white to yellow edge on the pupils. There is disagreement between sources on the exact range of lengths of D. polylepis, but the extreme reported values indicate that adults are 2.0 to 3.0 m, with an average length of 2.2 to 2.7m. Certain sources also claim rare cases of lengths of 4.3 and even 4.5m. Their smooth scales are at mid-body, in 23 to 25 (in some cases 21) rows.
Range length: 2.0 to 3.0 m.
Average length: 2.2-2.7 m.
Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry ; venomous
Sexual Dimorphism: sexes alike
- FitzSimons, V. 1970. A Field Guide to the Snakes of Southern Africa. London: Collins.
- Marais, J. 1985. Snake Versus Man. Johannesburg: Macmillan South Africa.
- Branch, B. 1988. Field Guide to the Snakes and Other Reptiles of Southern Africa. Cape Town: Struik Publishers.
Habitat and Ecology
Dendroaspis polylepis individuals prefer wooded savannah, rocky hills, or riverine forests with rocks or downed trees that provide cover. They may also be found hiding in hollow trees or termite mounds. Though they prefer traveling on the ground, they are also arboreal. If undisturbed, D. polylepis will maintain a permanent lair to which it returns when not hunting, basking, mating, or seeking refuge elsewhere.
Range elevation: 1800 (high) m.
Habitat Regions: tropical ; terrestrial
Terrestrial Biomes: savanna or grassland ; forest
Other Habitat Features: riparian
- Marais, J. 1992. A Complete Guide to the Snakes of Southern Africa. Halfway House: Southern Book Publishers.
Black mambas feed mostly on small mammals, including rodents, squirrels, and dassies or hyraxes. They also take birds occasionally. Black mambas strike once or twice and wait for the prey to become paralyzed and die before swallowing them. After ingestion, powerful acids digest the prey, sometimes within 8 to 10 hours.
Animal Foods: birds; mammals
Primary Diet: carnivore (Eats terrestrial vertebrates)
Very little information is available on the ecosystem roles of black mambas. They are important in controlling rodent populations.
There is no specific information on predators of Dendroaspis polylepis, but snakes in general have many. Predators will mainly target eggs or young snakes and may include: large reptiles such as crocodiles or monitors, large frogs, mongooses, foxes or jackals, birds of prey, and most notably, human beings. Though humans do not usually consume snakes, they often kill them out of fear. Snake eggs are also susceptible to being eaten by many types of scavengers.
Life History and Behavior
Communication and Perception
Dendroaspis polylepis shows little deviation from the common methods of communication and perception found in snakes. They use their eyesight mainly for detection of motion, and sudden movements will cause them to strike. The tongue is extended from the mouth to collect particles of air, which are then deposited in the vomeronasal organ on the roof of the mouth, which acts as a chemosensory organ. They have no external ears, but are quite adept at detecting vibrations from the ground. Like many snakes, when threatened, they will display aggression with a set of signals warning of the possibility of attack.
Communication Channels: visual ; acoustic
Perception Channels: visual ; tactile ; vibrations ; chemical
Bites and Venom
When threatened or hunting the black mamba bites its victim. It has and amazing top speed 12.5 miles per hour, which is fast enough to overtake a human running away. This makes it easy for the black mamba to bite its victim. It then bites with striking speed and delivers one of the most potent venoms in the world. It delivers on average 100-120 milligrams of venom, though only 10-15 is required to kill a human. The victim then receives many symptoms and eventually the victim experiences convulsions, cardiac arrest, respiratory arrest, and finally death. Death can happen 15 minutes to 3 hours after the injection of the venom, but deaths usually occur 30 to 60 minutes after the venom is injected. The mortality rate without antivenom is 100%, the highest of any snake. The South African Institute of Medical Research developed an effective antivenom.
No specific information was available for Dendroaspis polylepis, but some general assumptions can be made. Black mambas are oviparous. Young incubate inside the eggs for 2 to 3 months after being deposited. They break through the shell with an "egg-tooth". Upon hatching, young are fully functional and can fend for themselves. They have fully developed venom glands, and are dangerous just minutes after birth. The yolk of the egg is absorbed into the body and can nourish the young for quite some time.
There is not much information about the lifespan of snakes in the wild. The longest recorded lifespan of a captive mamba was 11 years, but actual lifespans could be much greater.
Status: captivity: 11 (high) years.
Status: captivity: 10.1 years.
Lifespan, longevity, and ageing
Black mambas mate during the early spring. Males will locate a suitable female by following a scent trail. Upon finding 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. Dendroaspis polylepis males will often engage in combat during the mating season. This act involves intertwining their bodies and raising their heads up to 1 m off the ground, which can also be mistaken for mating.
Mating System: polygynandrous (promiscuous)
Dendroaspis polylepis mate in the early spring. After mating, males and females return to their lairs. Within 2 to 3 months, females lay anywhere from 6 to 17 eggs, which will hatch within 2 to 3 months.
Breeding interval: Black mambas breed once yearly.
Breeding season: Mating occurs in the early spring, egg-laying during mid-summer.
Range number of offspring: 6 to 17.
Range gestation period: 80 to 90 days.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization ; oviparous
Black mambas do not interact beyond mating and males do not contribute effort to raising offspring. After the eggs have developed inside the female, she will deposit them in a burrow or other suitable hatching location and then abandon them. The young must fend for themselves directly from birth.
Parental Investment: pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Protecting: Female)
- Spawls, S., B. Branch. 1995. The Dangerous Snakes of Africa. London: Blandford.
- FitzSimons, V. 1970. A Field Guide to the Snakes of Southern Africa. London: Collins.
IUCN Red List Assessment
Red List Category
Red List Criteria
Black mambas are not endangered in any way, however, they do face a future threat due to human expansion. They are nervous animals and prefer to stay far away from humans. Human population expansion into their habitat could cause considerable habitat destruction and conflicts with human interests.
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: least concern
Relevance to Humans and Ecosystems
Economic Importance for Humans: Negative
Dendroaspis polylepis is one of the most dangerous snakes in the world. It is capable of delivering enough venom to kill a human being within 20 minutes. Its venom is a neurotoxin that causes paralysis and stops vital body functions. If bitten, victims must seek immediate medical attention. Usually, antivenin is administered, but in cases where the victim has already become severely incapacitated, they may require life-support until their nervous system recovers. Since it will sometimes take refuge in a populated area, such as the roof of a house or a farm pumphouse, encounters with humans are relatively frequent, and in rural areas, often fatal.
Negative Impacts: injures humans (bites or stings, venomous )
Economic Importance for Humans: Positive
Though many snakes are kept in captivity as pets, this is generally a bad idea with a snake as dangerous as Dendroaspis polylepis, so it can be assumed that they are not a valuable commodity in the pet trade industry. In fact, there have been reports of black mambas delivering fatal or near-fatal bites to well-informed captors. Their diet of mostly small rodents helps control pest populations to some extent.
Positive Impacts: controls pest population
The black mamba (Dendroaspis polylepis), also called the common black mamba or black-mouthed mamba, is the longest venomous snake in Africa and the second longest venomous snake in the world, behind the king cobra, averaging around 2.2 to 2.7 m (7.2 to 8.9 ft) in length, and sometimes growing close to lengths of 4 m (13 ft). It is by far the most feared snake in all of Africa and one of the most feared in the world. It is named for the black colour of the inside of the mouth rather than the colour of its scales which varies from dull yellowish-green to a gun-metal grey. It is the fastest snake in the world, capable of moving at 4.32 to 5.4 metres per second (11–19 km/h, 10–12 mph) for short distances. The black mamba has a reputation for being very aggressive, but like most snakes, it usually attempts to flee from humans unless threatened. Without rapid and vigorous antivenom therapy, a bite from a black mamba is almost always fatal.
- 1 Taxonomy and etymology
- 2 Description
- 3 Distribution and habitat
- 4 Behaviour and ecology
- 5 Reproduction
- 6 Venom
- 7 Conservation
- 8 References
- 9 External links
Taxonomy and etymology
Dendroaspis polylepis is classified under the genus Dendroaspis of the family Elapidae. The black mamba was first described in 1864 by Albert Günther, a German-born British zoologist, ichthyologist, and herpetologist. Soon after, a subspecies was identified, Dendroaspis polylepis antinorii (Peters, 1873), but this is no longer accepted as distinct. The genus and species name are derived from Ancient Greek words – Dendroaspis meaning "tree asp" (dendro is "tree", while aspis is "asp" which is understood to mean a "venomous snake") and polylepis, "many scaled", from poly "many" and lepis "scales". The name "black mamba" is given to the snake not because of its body colour but because of the ink-black colouration of the inside of its mouth, which it displays when threatened. In 1896, Boulenger combined the species (Dendroaspis polylepis) as a whole with the eastern green mamba, Dendroaspis angusticeps, and they were considered a single species from 1896 until 1946.
The adult black mamba's back skin colour is olive, brownish, gray, or sometimes khaki. A young snake is lighter, but not light enough to be confused with the different species of green mamba. Its underbody is cream-coloured, sometimes blended with green or yellow. Dark spots or blotches may speckle the back half of the body, and some individuals have alternating dark and light scales near the posterior, giving the impression of lateral bars. The inside of the mouth is dark blue to inky black. The head is large but narrow and elongated, with the shape of a coffin. It is a proteroglyphous snake, meaning it has immovable, fixed fangs at the front of the maxilla. The eyes are dark brown to black, with a silvery-white to yellow edge on the pupils. As they age, their colouration tends to get darker.
The species is the second-longest venomous snake in the world, exceeded in length only by the king cobra. Not all scientific sources agree on the range of lengths for this species, but adult specimens are 2.2 to 2.7 m (7.2 to 8.9 ft) in length on average, with a range of 2.0 to 3.8 m (6.6 to 12.5 ft). Some sources report maximum lengths of 4.3 to 4.5 m (14 to 15 ft). In the 1950s, a black mamba measuring 4.3 m (14 ft), known as "the King of the Mambas" in African Wildlife, was shot in Natal, South Africa. There is no real sexual dimorphism, and both male and female snakes of this species have a similar appearance and tend to be similar in size. Information regarding the lifespan of snakes in the wild is sparse; the longest recorded lifespan of a captive black mamba is 14 years, but actual maximum lifespans could be much greater.
|Dorsal at midbody||Ventral||Subcaudal||Anal plate||Upper labials||Upper labials to eye||Preoculars||Postoculars||Lower labials||Temporal|
|23-25 (rarely 21)||248–281||109–132 (paired)||Divided||7-10||4th (or 3rd to 4th)||3-4 (2-5)||3 (can be 4)||11-13 (10-14)||2+3 (variable)|
Distribution and habitat
Although it is a large diurnal snake, the distribution of the black mamba is the subject of much confusion in research literature, indicating the poor status of African herpetological zoogeography. However, the distribution of the black mamba in eastern Africa and southern Africa is well documented. Pitman (1974) gives the following range for the species' total distribution in Africa: northeastern Democratic Republic of the Congo, southwestern Sudan, South Sudan to Ethiopia, Eritrea, Somalia, southern Kenya, eastern Uganda, Tanzania, southwards to Mozambique, Swaziland, Malawi, Zambia, Zimbabwe and Botswana to KwaZulu-Natal in South Africa, and into Namibia; then northeasterly through Angola to the southeastern part of the Democratic Republic of Congo. According to CITES, the species is also found in Lesotho, Rwanda, and Djibouti. The black mamba is not commonly found above altitudes of 1,000 metres (3,300 ft), although the distribution of black mamba does reach 1,800 metres (5,900 ft) in Kenya and 1,650 metres (5,410 ft) in Zambia. The black mamba was recorded in 1954 in West Africa in the Dakar region of Senegal. However, this observation, and a subsequent observation that identified a second specimen in the region in 1956, have not been confirmed and thus the species' distribution in West Africa is inconclusive. The black mamba's western distribution contains gaps within the Central African Republic, Chad, Nigeria and Mali. These gaps may lead physicians to misidentify the black mamba and administer an ineffective antivenom. West of Ethiopia, it has a curious distribution, with few records. There is a single record from the Central African Republic, two from Burkina Faso, and as mentioned two unconfirmed sightings from Senegal, one from the Gambia, and a possible sighting in Cameroon. These sightings may indicate improper documentation, remaining populations from what was once a larger range, or new populations, indicating a growing range.
The black mamba has adapted to a variety of climates, ranging from savanna, woodlands, farmlands, rocky slopes, dense forests and humid swamps. The grassland and savanna woodland/shrubs that extend all the way from southern and eastern Africa to central and western Africa are the black mamba's typical habitat. The snake prefers more arid environments, such as semiarid, dry bush country, light woodland, and rocky outcrops. This species likes areas with numerous hills, as well as riverine forests. Black mambas often make use of abandoned termite mounds and hollow trees for shelter, which it goes back to everynight. The abandoned termite mounds are especially used when the snake is looking for somewhere to cool off, as the mounds are sort of a "natural air-conditioning" system. The structure of these mounds is very complex and elaborate. They have a network of holes, ducts, and chimneys that allow air to circulate freely, drawing heat away from the nest during the day – though without taking too much valuable moisture – while preventing the nest cooling too much at night. As a species which maintains a permanent home range throughout its entire life, the black mamba will always return to its lair at night within this home range if left undisturbed.
Behaviour and ecology
Though they prefer traveling on the ground, and they are considered to be a terrestrial species of snake, they are also arboreal. Black mambas maintain a home range, but are not considered highly territorial, preferring to flee from danger when threatened. They have a favoured home or lair usually in an abandoned termite mound, an aardvark burrow, a hollow tree or log, or a rock crevice. They prefer to avoid confrontation and will often attempt to retreat to their lair, attacking anything that gets in its way. This usually results when an threat or predator blocks the snake's direct path to its lair or refuge. A cornered black mamba will raise its head far off the ground, open its mouth, expand a narrow hood, flick its tongue and hiss before striking. If the attempt to scare away the attacker fails, it will strike repeatedly. Strikes will be numerous and rapid, and are often fatal to humans. If the threat slowly moves away from the mamba, the snake will usually retreat. Black mambas spend much of their time basking and will return often to a favoured sunny spot. A diurnal species, the black mamba is usually active from a few hours after sunrise until about an hour before dusk. In short bursts and over short distances, the black mamba can travel 11 to 19 km/h (6.8 to 12 mph), making it the fastest land snake in the world. Besides the relatively high speed with which it moves, the black mamba can strike accurately in any direction, even while moving fast. In striking, it throws its head upward from the ground for about two-fifths the lengths of its body.
Many snake experts have cited the black mamba as the world's most aggressive snake, noting tendency to attack without provocation. It can show an incredible amount of tenacity, fearlessness, and aggression when cornered, during breeding season, or when defending its territory. According to Swaziland-born snake handler and snake expert Thea Litschka-Koen:
Black mambas will kill a dog or several dogs if threatened and it happens quite often. We also find dead cows and horses! We were called by the frantic family late one evening. When we arrived minutes later, two small dogs had already died and two more were showing severe symptoms of envenomation. Within 15 minutes we had found and bagged the snake. By this time the other two dogs were also dead. The snake must have been moving through the garden when it was attacked by the dogs. It would have struck out defensively, biting all the dogs that came within reach. The snake was bitten in several places on its body as well and died about a week later.
— Thea Litschka-Koen
Communication and perception
Black mambas show little deviation from the common methods of communication and perception found in snakes. They primarily rely on their eyesight, their tongue, and ability to sense vibration to gather information from their environment. Their eyes are large and they have excellent eyesight which is used to detect motion, to view surroundings, and to help them carefully navigate and move about in their environment. Detection of quick or sudden movements will cause them to strike immediately. The vomeronasal organ (Jacobson's organ), a chemosensory organ located on the roof of their mouth, is involved in the black mambas social chemical communication and in hunting prey. They collect environment stimuli, such as molecules from the air and nearby objects by extending their forked tongue from their mouth. These chemical elements are then deposited in the vomeronasal organ when the tongue is retracted. They lack external auditory structures and cannot hear airborne sounds, but the part of their body in direct contact with the ground is very sensitive to vibrations; thus they are able to sense other animals approaching by detecting faint vibrations in the air and on the ground. Like many snakes, when threatened, they will become defensive and aggressive, displaying a set of warning signals of a possibility of attack.
Hunting and prey
When hunting, the black mamba is often seen travelling with its head raised well above ground level, quickly moving forward in search of prey. Once prey is detected, the black mamba freezes before hurling itself forward and issuing several quick bites, swiftly killing its prey. If the prey attempts to escape, the black mamba will follow up its initial bite with a series of strikes. It will release larger prey after biting it, but smaller prey, such as birds or rats, are held until the prey's muscles stop moving. Black mambas feed on a variety of prey, especially mammals, including hyraxes, rats, mice, squirrels, bats, bushbabies and elephant shrews. They have also been known to prey on birds and small chickens, as well as other snakes, such as the puff adder and Cape cobra. A large specimen has even been recorded eating a young blue duiker (Philantomba monticola). After ingestion, powerful acids digest the prey, sometimes within 8 to 10 hours.
There are no specific predators of the black mamba, but snakes in general tend to have many. Large adult black mambas have no specific predators other than humans. Humans do not usually consume black mambas; they often kill them out of fear. Other predators will often target eggs or very young mambas, and known predators are large reptiles such as crocodiles or monitors, mongooses, foxes or jackals, and birds of prey. Mamba eggs are also susceptible to being eaten by many types of scavengers. Juvenile mambas are also subject to predation from Cape file snakes.
Black mambas breed only once a year. The breeding season begins in the spring, which occurs around the month of September in the African regions where these snakes occur, as much of sub-Saharan Africa is in the Southern Hemisphere. In this period, the males fight over females. Agonistic behaviour for black mambas involves wrestling matches in which opponents attempt to pin each other's head repeatedly to the ground. Fights normally last a few minutes, but can extend to over an hour. The purpose of fighting is to secure mating rights to receptive females nearby during the breeding season. Beyond mating, males and females do not interact. Males locate a suitable female by following a scent trail. Upon finding his mate, he will thoroughly inspect her by flicking his forked tongue across her entire body. Males are equipped with two hemipenes. After a successful and prolonged copulation, the eggs develop in the female's body for about 60 days. During this period, the female seeks a suitable place to lay the eggs. Females prefer using abandoned termite mounds as nests. Mature females lay between 15 and 25 eggs, which they hide very well and guard very aggressively. The eggs incubate for about 60 days before hatching. The hatchlings are about 50 centimetres (20 in) in length and are totally independent after leaving the eggs, hunting and fending for themselves from birth. Young hatchlings are as venomous as the adults, but do not deliver as much venom per bite as an adult snake would.
Like many snakes, the venom toxicity (LD50) of individual specimens can show considerable variation which can be due to geographical region, seasonal variation, diet, habitat, and age-dependent change. The venom of the black mamba is a protein of low molecular weight and as a result is able to spread extraordinarily rapidly within the bitten tissue. It is considered to be the most rapid-acting snake venom. and consists mainly of highly potent neurotoxins; it also contains cardiotoxins, fasciculins, and calciseptine. Median lethal dose LD50 values for this species' venom varies tremendously from one toxinological study to the next. Ernst and Zug et al. 1996 listed a value of 0.05 mg/kg for subcutaneous injection, while Minton & Minton list a value of 0.25 mg/kg for intravenous injection. Spawls & Branch and Minton & Minton both listed the SC LD50 at 0.28 mg/kg and Brown lists a value of 0.12 mg/kg SC.
It is estimated that only 10 to 15 milligrams (0.15 to 0.23 gr) will kill a human adult, and its bites delivers about 120 milligrams (1.9 gr) of venom on average, although they may deliver up to 400 milligrams (6.2 gr) of venom in a single bite. Its bite is often called "the kiss of death" because, before antivenom was widely available, the mortality rate from a bite was 100% since this species always delivers fatal dosage of venom during every envenomation. Severe black mamba envenomation can kill a person in 30 minutes, but sometimes it takes up to 2–3 hours, depending upon many factors. The fatality duration and rate depends on various factors, such as the health, size, age, and psychological state of the victim, the penetration of one or both fangs from the snake, the amount of venom injected, the pharmacokinetics of the venom, the location of the bite, and its proximity to major blood vessels. The health of the snake and the interval since it last used its venom mechanism is important, as well. A polyvalent antivenom produced by the South African Institute for Medical Research (SAIMR) is used to treat all black mamba bites from different localities. If bitten, severe neurotoxicity invariably ensues. Neurological, respiratory, and cardiovascular symptoms rapidly begin to manifest, usually within ten minutes or less. Common symptoms are rapid onset of dizziness, drowsiness, coughing or difficulty breathing, convulsions, and an erratic heartbeat. Other common symptoms which come on rapidly include neuromuscular symptoms, shock, loss of consciousness, hypotension, pallor, ataxia, excessive salivation (oral secretions may become profuse and thick), limb paralysis, nausea and vomiting, ptosis, fever, and very severe abdominal pain. Local tissue damage appears to be relatively infrequent and of minor severity in most cases of black mamba envenomation. Edema is typically minimal. Myocardial infarctions (heart attacks), although rare, have been reported in black mamba envenomation. Death is due to suffocation resulting from paralysis of the respiratory muscles. Due to antivenom, a bite from a black mamba is no longer a certain death sentence. But in order for the antivenom therapy to be successful, vigorous treatment and large doses of antivenom must be administered very rapidly post-envenomation. In case studies of black mamba envenomation, respiratory paralysis has occurred in less than 15 minutes.
In a case of 10 envenomations (4 female, 6 male) in South Africa all ten received medical treatment but only five lived. Two developed respiratory paralysis in ten minutes, and three patients became apneic in just under 30 minutes post-envenomation. The other five patients did not experience the same severity of neurotoxicity, but all were strongly symptomatic upon arrival at the hospital. Symptoms initially included mild swelling at bite site, confusion, excessive sweating, urinary incontinence, fecal incontinence, loss of coordination, ptosis, erratic heartbeat, drowsiness, and breathing difficulties. Out of the 10 patients, five were fatal despite prompt hospitalization and induction of medical treatment. Three of the patients died in between 45 and 60 minutes post-envenomation, while the other two died in under 30 minutes. The other five patients survived but all of them required massive amounts of antivenom and assisted mechanical ventilation for a prolonged period. Three of the patients were on mechanical ventilation for 10 days, while the other two required assisted mechanical ventilation for 16 days. Cases of this nature are not at all uncommon among cases of envenomation by the black mamba.
Envenomation by this species invariably causes very severe neurotoxicity due to the fact that black mambas often strike repeatedly in a single lunge, biting the victim up to 12 times in extremely rapid succession. Such an attack is very fast, lasting less than one second and so it appears to be a single strike and single bite. With each bite the snake delivers anywhere from 100 to 400 milligrams (1.5 to 6.2 gr) of a rapid-acting and highly toxic venom. As a result, the doses of antivenom required for successful treatment are often massive (10–40 vials) for bites from this species. In addition to antivenom therapy, endotracheal intubation and mechanical ventilation are required for supportive therapy.
Because of various factors, including the toxicity and high venom yield, the fact that untreated bites have a mortality rate of 100%, as well as aggressiveness, speed, agility, and size of black mamba, it is often considered to be the world's deadliest and most aggressive snake species. This view was shared by Charles Pitman. Nevertheless, attacks on humans are relatively rare, as the snakes usually avoid confrontation with humans and their occurrence in highly populated areas is not as common as some other African species of venomous snakes.
Mamba venom is made up mostly of dendrotoxins (dendrotoxin-k – "Toxin K", dendrotoxin-1 – "Toxin 1", dendrotoxin-3 – "Toxin 3", dendrotoxin-7 – "Toxin 7", among others), fasciculins, and calciseptine. Being a protein of low molecular weight, the venom and its constituents are able to spread extraordinarily rapidly within the bitten tissue, so black mamba venom is the most rapid-acting of all snake venoms. The dendrotoxins disrupt the exogenous process of muscle contraction by means of the sodium potassium pump. Toxin K is a selective blocker of voltage-gated potassium channels, and Toxin 1 inhibits the K+ channels at the pre and postsynaptic level in the intestinal smooth muscle. It inhibits Ca2+-sensitive K+ channels from rat skeletal muscle‚ incorporated into planar bilayers (Kd = 90 nM in 50 mM KCl), Toxin 3 inhibits M4 receptors, while Toxin 7 inhibits M1 receptors. The calciseptine is a 60 amino acid peptide which acts as a smooth muscle relaxant and an inhibitor of cardiac contractions. It blocks K+-induced contraction in aortic smooth muscle and spontaneous contraction of uterine muscle and portal vein. The venom is highly specific and virulently toxic. In one experiment, the death time of a mouse after subcutaneous injection of some toxins studied, was around seven minutes. However, black mamba venom can kill a mouse after 4.5 minutes.
Black mamba venom also contains proteins, mambalgins, which in mice act as an analgesic as strong as morphine, but without most of the side-effects. Mambalgins cause much less tolerance than morphine and no respiratory distress. They act through a completely different route, acid-sensing ion channels. Laboratory tests suggest that the pain-killing effect on humans may be similar, but this had not been tested as of October 2012[update]. Researchers were puzzled about the advantage this substance could give the snakes.
Availability of treatment
Venomous snakebites are rampant in sub-Saharan Africa. Although antivenom is now widely available and bite victims can rapidly access adequate treatment in most of Africa's medium to large cities and nearby areas, some severely impoverished African nations do not always have antivenom in stock, as it is very expensive, even by Western standards. Most of those bitten by a venomous African snake species require 5 vials of antivenom as an initial dose. A single vial of antivenom can cost anywhere from USD $160-$200, and black mamba envenomation is the costliest to treat, as 10-12 vials of antivenom are often required as an initial starting dose and more than 20-30 vials are often required for effective treatment. Some victims may require up to 40 vials. As a result of the severe nature of black mamba bites and the cost of antivenom required to treat such a bite, deaths due to black mamba envenomation are very common in Swaziland and the rate of mortality is close to 100%. Other contributing factors besides the lack of antivenom are lack of mechanical ventilation equipment, proper envenomation symptom control, and drugs. Some victims will not access medical care, but rather go to a traditional healer or witch doctor. However, Swaziland does have "Antivenom Swazi", a charity whose mission is to raise enough funds to create a "bank" of antivenom for treating snakebites, but they are specifically focused on treating black mamba bite victims in Swaziland. Although bites attributed to this species are less likely compared to most African cobra species and to the puff adder, the mortality rate is significantly higher among those envenomed by black mambas. In Zimbabwe, the black mamba and green mamba are responsible for 18% of bites, but the number of deaths due to mamba envenomation is equal to the number of deaths among those bitten by cobras, who are responsible for double the amount of bites at 37%. In Tanzania, while the black mamba is second to the puff adder in causing human fatalities, the puff adder bites almost six times the number of people that the black mamba does. A survey of snakebites in South Africa from 1957 to 1963 recorded over 900 venomous snakebites, but only seven of these were confirmed black mamba bites. From the 900 bites, only 21 ended in fatalities, including all seven black mamba bites – a 100% mortality rate. This and many other studies which found a 100% fatality rate among black mamba bites stimulated the production of a specific mamba antivenom, and in 1967 Louw reported the first successful treatment of two black mamba bites with a specific antivenom prepared by the South African Institute of Medical Research. This was the first time that any victim of a black mamba bite was scientifically documented to survive envenomation.
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 2010, and it was classed as such due to its very large distribution
Fear, myths, and killings of black mambas
The black mamba faces human persecution because of its negative reputation throughout Africa. With the increasing amount of its territory being inhabited by humans, the black mamba often finds itself cornered with no escape. In this situation, it will stand its ground and display fearsome tenacity and explosive aggression while hissing loudly and striking repeatedly. A group of people is usually required to kill it, as it is very fast and agile, striking in all directions while a third of its body is 3–4 feet (0.91–1.2 m) above the ground. The deep fear of this snake stems not only from its reputation for aggression, speed, and venom toxicity, but from stories and legends that have been passed down from generation to generation. throughout sub-Saharan Africa. Besides its very large geographical distribution, the species has no specific threats or predators that have been reported, and this species is not undergoing significant population declines.
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