Black Mamba

## Description

The Black mamba (Dendroaspis polylepis) is a species of highly venomous snake belonging to the family Elapidae. It is native to parts of sub-Saharan Africa. It is the second-longest venomous snake after the King cobra. Despite its reputation as a formidable and highly aggressive species, the Black mamba attacks humans only if it is threatened or cornered.

## Appearance

Black mambas have a coffin-shaped head with a somewhat pronounced brow ridge and a medium-sized eye. These snakes vary considerably in color, including olive, yellowish-brown, khaki, and gunmetal but are rarely black. The scales of some individuals may have a purplish sheen. Black mambas have greyish-white underbellies and the inside of the mouth is 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 color. Juvenile snakes are lighter in color than adults; these are typically grey or olive green and darken as they age.

## Distribution

Black mambas inhabit a wide range in sub-Saharan Africa; their range includes the Central African Republic, the Democratic Republic of the Congo, Ethiopia, Eritrea, Somalia, Kenya, Uganda, Tanzania, Mozambique, Malawi, Zambia, Zimbabwe, Botswana, South Africa, Namibia, and Angola. These snakes prefer moderately dry environments such as light woodland and scrub, rocky outcrops, mountain peaks, and semi-arid savanna. They also inhabit moist savanna, and lowland forests and may visit agricultural areas.

## Lifestyle

Black mambas are both terrestrial and arboreal creatures. On the ground, they move with their head and neck raised, and typically use termite mounds, abandoned burrows, rock crevices, and tree cracks as shelter. Black mambas are solitary; they are diurnal and tend to bask in the morning and again in the afternoon. They may return daily to the same basking site. Skittish and often unpredictable, Black mambas are agile and can move quickly. In the wild, they seldom tolerate humans approaching more closely than about 40 meters (130 ft). When mambas perceive a threat, they retreat into the brush or a hole. When confronted they are likely to engage in a threat display, gaping to expose their black mouth and flicking their tongue. They may also hiss and spread their neck flap. 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 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 the ability to retreat.

## Venom

The Black mamba is the most feared snake in Africa because of its size, aggression, venom toxicity, and speed of onset of symptoms following envenomation, and is classified as a snake of medical importance by the World Health Organization. A survey in South Africa from 1957 to 1979 recorded 2553 venomous snakebites, 75 of which were confirmed as being from Black mambas. A mamba-specific antivenom was introduced in 1962, followed by a fully polyvalent antivenom in 1971. Unlike many venomous snake species, Black mamba venom does not contain protease enzymes. Its bites do not generally cause local swelling or necrosis, and the only initial symptom may be a tingling sensation in the area of the bite. The snake tends to bite repeatedly and let go, so there can be multiple puncture wounds. Its bite can deliver about 100-120 mg of venom on average; the maximum recorded dose is 400 mg. The murine median lethal dose (LD50) when administered intravenously has been calculated at 0.32 and 0.33 mg/kg. Bites were often fatal before antivenom was widely available.

The venom is predominantly neurotoxic, and symptoms often become apparent within 10 minutes. Early neurological signs that indicate severe envenomation include a metallic taste, drooping eyelids (ptosis), and gradual symptoms of bulbar palsy. The bite of a black mamba can cause a collapse in humans within 45 minutes. Without appropriate antivenom treatment, symptoms typically progress to respiratory failure, which leads to cardiovascular collapse and death. This typically occurs in 7 to 15 hours.

## Diet

Black mambas are carnivores and mostly prey on small vertebrates such as birds, particularly nestlings and fledglings, and small mammals like rodents, bats, hyraxes, and bushbabies. They generally prefer warm-blooded prey but will also consume other snakes.

## Reproduction

Black mambas are polygynandrous (promiscuous); this means that both males and females mate with multiple partners. The breeding season spans from September to February. Rival males compete by wrestling, attempting to subdue each other by intertwining their bodies and wrestling with their necks. During mating, the male will slither over the dorsal side of the female while flicking its tongue. The female will signal its readiness to mate by lifting its tail and staying still. Black mambas are oviparous; females lay a clutch of 6-17 eggs. The eggs are elongated oval in shape, typically 60-80 mm (2.4-3.1 in) long and 30-36 mm (1.2-1.4 in) in diameter. Incubation lasts around 2 to 3 months. When hatched, the young range from 40-60 cm (16-24 in) in length. They are independent directly from birth and have to be able to care for themselves. Snakelets may grow quickly, reaching 2 m (6 ft 7 in) after their first year. Juvenile Black mambas are very apprehensive and can be deadly like adults.

## Population

### Population threats

There are no major threats to the Black mamba at present.

### Population number

According to IUCN, the Black mamba is locally common and widespread throughout its range but no overall population estimate is available. Currently, this species is classified as Least Concern (LC) on the IUCN Red List and its numbers today are stable.

### Ecological niche

Black mambas play a very important ecological role in their environment as they help to control populations of small rodents they prey on.