Black Mamba (Dendroaspis polylepis): Facts, Speed and Venom

Appearance

The black mamba has a long, thin, cylindrical body, smooth scales and a narrow, “coffin-shaped” head with a slight brow ridge above medium-sized eyes. The upper body ranges from olive and yellowish-brown to khaki, gunmetal gray and dark gray-brown, sometimes with a faint purplish sheen. The belly is grayish white or cream. Some individuals show darker mottling or faint diagonal bands toward the tail.

The feature that gives the snake its name is hidden most of the time. The lining of the mouth is dark bluish-gray to almost black, and the snake displays it by gaping wide when it feels cornered. Our article Why is the black mamba called black? explains the name and how to tell it from the green mambas.

Young black mambas are lighter than adults, usually gray or olive green, and darken as they grow. They are still duller than the bright green mambas, which are separate species. Like other members of the cobra family (Elapidae), the black mamba has fixed fangs at the front of the upper jaw; they are relatively short, up to about 6.5 mm (0.26 in).

How big do black mambas get?

Adults usually measure 2–3 m (6.6–9.8 ft), with an average of roughly 2.2–2.7 m (7.2–8.9 ft). Specimens of 4.3–4.5 m (14–15 ft) have been reported, but such sizes are exceptional and poorly documented. Among venomous snakes worldwide, only the king cobra grows longer.

Because it is so slender, the black mamba is light for its length. Typical adults weigh about 1–1.6 kg (2.2–3.5 lb). In one small study of seven snakes, weights ranged from about 520 g (18 oz) for a 1 m (3.3 ft) snake to 2.4 kg (5.3 lb) for one 2.57 m (8.4 ft) long. Males and females look alike and reach similar sizes.

Habitat and range

The black mamba lives across a wide part of sub-Saharan Africa. Its stronghold is eastern and southern Africa, from Eritrea, Ethiopia and Somalia south through Kenya, Tanzania, Mozambique, Zambia, Zimbabwe and Botswana to South Africa, Namibia and Angola. It also occurs in parts of central Africa and in a few areas of West Africa, such as Burkina Faso, although records from the far west, including Senegal, are disputed.

It prefers fairly dry, open country: light woodland, scrub, rocky outcrops and semi-arid savanna. It also uses moist savanna, riverine forest and lowland forest in some areas. Most records come from below about 1,000 m (3,300 ft), but the snake has been found up to about 1,800 m (5,900 ft) in Kenya.

Black mambas rely on secure shelters. They use termite mounds, abandoned burrows of other animals, rock crevices and hollow trees, and an undisturbed snake may return to the same lair for months or years. Although it spends much of its time on the ground, it is also a skilled, fast climber.

Diet and hunting

The black mamba is a carnivore that feeds mainly on warm-blooded prey. Rodents make up a large part of its diet, along with squirrels, hyraxes (dassies), young dwarf mongooses, other small mammals and birds, especially nestlings. It occasionally eats other snakes.

It is an active daytime hunter that often searches from a permanent lair. A study in South Africa found that most prey was small, weighing only a few percent of the snake’s own body mass. The mamba usually strikes once or several times, then lets go and waits for the venom to work before following and swallowing the prey whole. Digestion is fast for a snake, and a meal can be fully digested in about 8–10 hours in warm conditions.

The venom suits this lifestyle. Fast-acting nerve toxins stop prey before it can run far, and releasing the animal keeps the snake safe from bites and scratches.

Behavior and speed

Black mambas are diurnal, meaning active by day. In South Africa they have been recorded basking in the morning and again in the afternoon, often at a favorite sunny spot close to their shelter. They live alone and are shy and alert; in the wild they seldom let people approach closer than about 40 m (130 ft) before slipping away.

When it cannot escape, a black mamba puts on a threat display. It raises the front part of its body, spreads a narrow hood, opens its black mouth wide and may hiss. Any sudden movement can then trigger a series of rapid strikes. Because it can raise a large part of its body off the ground, bites on people can land on the upper body.

The black mamba is one of the fastest snakes, but its speed is often exaggerated. The most widely cited measured figure is about 11 km/h (7 mph) over a short distance, and higher estimates of 16–20 km/h (10–12 mph) refer to brief bursts on smooth ground. Read How fast is a black mamba? for how snake speed is measured and why “faster than a horse” claims are wrong.

Reproduction and life cycle

The breeding season in southern Africa falls roughly between September and February. Rival males fight by twisting their bodies together and trying to push each other’s head down; the wrestling can look like courtship, but it is a contest between males. Males find females by following scent trails.

The black mamba is oviparous, which means it lays eggs. About two to three months after mating, the female lays a clutch of 6–17 elongated eggs in a burrow, termite mound or other sheltered spot and then leaves them. The eggs hatch after roughly 80–90 days. Hatchlings are 40–60 cm (16–24 in) long and fully independent, with working venom glands from the start.

Young mambas grow fast and may approach 2 m (6.6 ft) within their first year. Little is known about lifespan in the wild. The longest recorded lifespan in captivity is about 11 years, and wild snakes may live longer.

Venom

Black mamba venom is mainly neurotoxic, meaning it attacks the nervous system. Its main toxins are dendrotoxins, which overstimulate nerves, and three-finger toxins, which block the signals between nerves and muscles and can cause paralysis. Unlike many vipers, it causes little local swelling or tissue damage.

In laboratory tests on mice, its venom has a subcutaneous LD50 of about 0.28–0.32 mg/kg (the dose that kills half of the test animals). That is very potent, but several Australian snakes, kraits and sea snakes score higher; see our ranking of the most venomous snakes. What makes the black mamba so dangerous is the combination of potent venom, a large venom yield of around 100–120 mg per bite on average, repeated strikes and fast onset of symptoms.

Before antivenom, a serious bite was usually fatal. A mamba-specific antivenom was introduced in South Africa in 1962, and today most people who receive appropriate hospital treatment in time survive. Bites are still a real problem in remote rural areas far from clinics, which is why the question Is the black mamba the deadliest snake? has a more complicated answer than its reputation suggests.

Black mamba venom is also of scientific interest. Toxins called mambalgins block certain pain-sensing channels in nerves, and researchers are studying them as a possible starting point for new painkillers.

Predators and threats

Adult black mambas have few natural predators. Brown snake eagles are known to kill adults at least 2.7 m (8.9 ft) long, and tawny eagles and martial eagles also take them. Mongooses and honey badgers sometimes attack mambas and have some resistance to the nerve toxins, as described in Are honey badgers immune to venom? Black mambas have also been found in the stomachs of Nile crocodiles.

Young snakes face many more enemies, including southern ground hornbills, owls, hooded vultures and snake-eating snakes such as the Cape file snake. Like the eggs of other snakes, unguarded mamba eggs are also at risk from egg-eating predators.

Conservation status

The IUCN Red List classes the black mamba as Least Concern, based on its huge range across sub-Saharan Africa and no documented overall decline. Local threats include habitat loss to farmland and settlements and the killing of snakes by people who fear them. Because mambas eat many rodents, they help control animals that damage crops and stored food.

Myths and facts

Myth: black mambas chase people. The snake’s first choice is to escape. Many “chasing” stories come from a mamba racing toward its shelter while a person stands in its path.

Myth: a black mamba can outrun a galloping horse or a car. Measured speeds are around 11 km/h (7 mph), and even generous estimates stay at or below about 20 km/h (12 mph). A horse can gallop at several times that speed.

Myth: black mambas are black. The body is olive to gray-brown; only the inside of the mouth is close to black.

Myth: a mamba bite is always fatal. It is a medical emergency, but many people survive with prompt treatment and antivenom. If anyone is bitten by any snake, seek emergency medical help immediately.

Relationship with people

The black mamba is probably the most feared snake in Africa and features in many local stories; the word “mamba” comes from the Zulu name imamba. Encounters happen mostly in farmland, around homesteads and in savanna reserves, where the snake may hunt rodents near buildings.

The safest approach is simple: give any large snake plenty of room, never try to catch, corner or kill it, and let it move away. Keep a clear path open so the snake can retreat. If a bite does happen, call emergency services or get to a hospital immediately: 911 in the US, 112 in the EU or 999 in the UK, or the local emergency number in Africa.