Black mamba
The black mamba is a species of highly venomous snake belonging to the family Elapidae. It is native to parts of sub-Saharan Africa. First formally described by Albert Günther in 1864, it is the second-longest venomous snake after the king cobra; mature specimens generally exceed and commonly grow to. Specimens of have been reported. It varies in colour from grey to dark brown. Juvenile black mambas tend to be more pale in colour than adults, and darken with age. Despite the common name, the black mamba is not black; the colour name describes rather the inside of its mouth, which it displays when feeling threatened.
The species is both terrestrial and arboreal ; it inhabits savannah, woodland, rocky slopes and in some regions, dense forest. It is diurnal and is known to prey on birds and small mammals. Over suitable surfaces, it can move at speeds up to for short distances. Adult black mambas have few natural predators.
In a threat display, the black mamba usually opens its inky-black mouth, spreads its narrow neck-flap and sometimes hisses. It is capable of striking at considerable range and may deliver a series of bites in rapid succession. Its venom is primarily composed of neurotoxins that often induce symptoms within ten minutes, and is frequently fatal unless antivenom is administered. Despite its reputation as a formidable and highly aggressive species, the black mamba attacks humans only if it is threatened or cornered. It is rated as least concern on the International Union for Conservation of Nature 's Red List of Threatened Species.
Taxonomy
The first formal description of the black mamba was made in 1864 by German-born British zoologist Albert Günther. A single specimen was one of many species of snake collected by John Kirk, a naturalist who accompanied David Livingstone on the 1858–1864 Second Zambesi expedition. This specimen is the holotype and is housed in the Natural History Museum, London. The generic name of the species is derived from the Ancient Greek words dendron, "tree", and aspis "asp", and the specific epithet polylepis is derived from the Ancient Greek poly meaning "many" and lepis meaning "scale". The term "mamba" is derived from the Zulu word "imamba". In Tanzania, a local Ngindo name is ndemalunyayo because it supposedly clips grass.In 1873, German naturalist Wilhelm Peters described Dendraspis Antinorii from a specimen in the museum of Genoa that had been collected by Italian explorer Orazio Antinori in what is now northern Eritrea. This was subsequently regarded as a subspecies and is no longer held to be distinct. In 1896, Belgian-British zoologist George Albert Boulenger combined the species Dendroaspis polylepis as a whole with the eastern green mamba, a lumping diagnosis that remained in force until 1946 when South African herpetologist Vivian FitzSimons again split them into separate species. A 2016 genetic analysis showed the black and eastern green mambas are each other's closest relatives, and are more distantly related to Jameson's mamba, as shown in the cladogram below.
Description
The black mamba is a long, slender, cylindrical snake. It has a coffin-shaped head with a somewhat pronounced brow ridge and a medium-sized eyes. The adult snake's length typically ranges from but specimens have grown to lengths of. It is the longest species of venomous snake in Africa and the second-longest venomous snake species overall, exceeded in length only by the king cobra. The black mamba is a proteroglyphous snake, with fangs up to in length, located at the front of the maxilla. The tail of the species is long and thin, the caudal vertebrae making up 17–25% of its body length. The body mass of black mambas has been reported to be about, although a study of seven black mambas found an average weight of, ranging from for a specimen of total length to for a specimen of total length.Specimens vary considerably in colour, including olive, yellowish-brown, khaki and gunmetal but are rarely black. The scales of some individuals may have a purplish sheen. Individuals occasionally display dark mottling towards the posterior, which may appear in the form of diagonal crossbands. Black mambas have greyish-white underbellies. The common name is derived from the appearance of the inside of the mouth, dark bluish-grey to nearly black. Mamba eyes range between greyish-brown and shades of black; the pupil is surrounded by a silvery-white or yellow colour. Juvenile snakes are lighter in colour than adults; these are typically grey or olive green and darken as they age.
Scalation
The number and pattern of scales on a snake's body are a key element of identification to species level. The black mamba has between 23 and 25 rows of dorsal scales at midbody, 248 to 281 ventral scales, 109 to 132 divided subcaudal scales, and a divided anal scale. Its mouth is lined with 7–8 supralabial scales above, with the fourth and sometimes also the third one located under the eye, and 10-14 sublabial scales below. Its eyes have 3 or occasionally 4 preocular and 2–5 postocular scales.Distribution and habitat
The black mamba inhabits a wide range in sub-Saharan Africa; its range includes Burkina Faso, Cameroon, Central African Republic, Democratic Republic of the Congo, South Sudan, Ethiopia, Eritrea, Somalia, Kenya, Uganda, Tanzania, Burundi, Rwanda, Mozambique, Eswatini, Malawi, Zambia, Zimbabwe, Botswana, South Africa, Namibia, and Angola. The black mamba's distribution in parts of West Africa has been disputed. In 1954, the black mamba was recorded in the Dakar region of Senegal. This observation, and a subsequent observation that identified a second specimen in the region in 1956, has not been confirmed and thus the snake's distribution in this area is inconclusive.The species prefers moderately dry environments such as light woodland and scrub, rocky outcrops and semi-arid savanna. It also inhabits moist savanna and lowland forests. It is not commonly found at altitudes above, although its distribution does include locations at in Kenya and in Zambia. It is rated as a species of least concern on the International Union for Conservation of Nature 's Red List of endangered species, based on its huge range across sub-Saharan Africa and no documented decline.
Behaviour and ecology
The black mamba is both terrestrial and arboreal. On the ground, it moves with its head and neck raised, and typically uses termite mounds, abandoned burrows, rock crevices and tree cracks as shelter. Black mambas are diurnal; in South Africa, they are recorded to bask between 7 and 10 am and again from 2 to 4 pm. They may return daily to the same basking site.Skittish and often unpredictable, the black mamba is agile and can move quickly. In the wild, black mambas seldom tolerate humans approaching more closely than about. When it perceives a threat, it retreats into brush or a hole. When confronted, it is likely to engage in a threat display, gaping to expose its black mouth and flicking its tongue. It also is likely to hiss and spread its neck into a hood similar to that of the cobras in the genus Naja.
During the threat display, any sudden movement by the intruder may provoke the snake into performing a series of rapid strikes, leading to severe envenomation. The size of the black mamba and its ability to raise its head a large distance from the ground enables it to launch as much as 40% of its body length upwards, so mamba bites to humans can occur on the upper body. The black mamba's reputation for being ready to attack is exaggerated; it is usually provoked by perceived threats such as the blocking of its movements and ability to retreat. The species' reputed speed has also been exaggerated; it cannot move more quickly than.
Reproduction and lifespan
The black mamba's breeding season spans from September to February, following the drop in temperature which occurs from April to June. Rival males compete by wrestling, attempting to subdue each other by intertwining their bodies and wrestling with their necks. Some observers have mistaken this for courtship. During mating, the male will slither over the dorsal side of the female while flicking his tongue. The female will signal her readiness to mate by lifting her tail and staying still. The male will then coil himself around the posterior end of the female and align his tail ventrolaterally with the female's. Intromission may last longer than two hours and the pair remain motionless apart from occasional spasms from the male.The black mamba is oviparous; the female lays a clutch of 6–17 eggs. The eggs are elongated oval in shape, typically long and in diameter. When hatched, the young range from in length. They may grow quickly, reaching after their first year. Juvenile black mambas are very apprehensive and can be deadly like the adults. The black mamba is recorded to live up to 11 years and may live longer.