Dendroaspis polylepis

Geographic Range

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 ethiopian
  • native native

Habitat

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.

• Habitat Regions
• tropical tropical
• terrestrial terrestrial

• Terrestrial Biomes
• savanna or grassland savanna or grassland
• forest forest

• Other Habitat Features
• riparian riparian

Physical Description

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.

• Other Physical Features
• heterothermic heterothermic
• venomous venomous

• Sexual Dimorphism
• sexes alike

Development

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.

Reproduction

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) 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.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• sexual sexual
• fertilization fertilization
• oviparous 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

Lifespan/Longevity

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.

Behavior

Dendroaspis polylepis are shy and secretive. They prefer to avoid confrontation but will become aggressive when threatened. This usually results when an intruder blocks the snake’s direct path to its home 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. Strikes will be numerous and rapid, and can be fatal to humans. If the intruder 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 favored sunny spot. They are diurnal, usually active from a few hours after sunrise until about an hour before dusk. Black mambas are capable of relatively high speeds, up to 20 km/h (about 12.5mph), traveling with up to a third of its body raised off the ground. Black mambas are adept at climbing trees and do so very quickly. They maintain a home range, but are not considered highly territorial, preferring to flee from danger when threatened.

• Key Behaviors
• arboreal arboreal
• terricolous
• diurnal diurnal
• sedentary sedentary
• solitary solitary
• territorial territorial

Home Range

Home range sizes can vary based on habitat characteristics and prey density.

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 visual
• acoustic acoustic

• Perception Channels
• visual visual
• tactile tactile
• vibrations vibrations
• chemical chemical

Food Habits

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.

• Primary Diet
• carnivore carnivore
  • eats terrestrial vertebrates

• Animal Foods
• birds
• mammals

Predation

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.

Ecosystem Roles

Very little information is available on the ecosystem roles of black mambas. They are important in controlling rodent populations.

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

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 venomous

Conservation Status

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.

Other Comments

Black mambas ( Dendroaspis polylepis ) are one of the most feared snake species in the world, and certainly the most feared in Africa. Its combination of speed, unpredictable aggression, and potent venom make it an extremely dangerous species. People who encounter this snake experience a combination of awe and terror, hopefully followed by a quickly fleeing snake.

Additional Links

Encyclopedia of Life

Contributors

Tanya Dewey (editor), Animal Diversity Web.

Pamela Rasmussen (editor, instructor), Michigan State University, Randy Schott (author), Michigan State University.

References

Branch, B. 1988. Field Guide to the Snakes and Other Reptiles of Southern Africa . Cape Town: Struik Publishers.

FitzSimons, V. 1970. A Field Guide to the Snakes of Southern Africa . London: Collins.

Marais, J. 1992. A Complete Guide to the Snakes of Southern Africa . Halfway House: Southern Book Publishers.

Marais, J. 1985. Snake Versus Man . Johannesburg: Macmillan South Africa.

Spawls, S., B. Branch. 1995. The Dangerous Snakes of Africa . London: Blandford.