Animal Diversity Web

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. (Spawls and Branch, 1995)

• Biogeographic Regions
• ethiopian
  • 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. (Marais, 1992; Spawls and Branch, 1995)

• Habitat Regions
• tropical
• terrestrial

• Terrestrial Biomes
• savanna or grassland
• forest

• Other Habitat Features
• riparian

• Range elevation

  1800 (high) m

  5905.51 (high) ft

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. (Branch, 1988; FitzSi­mons, 1970; Marais, 1985; Spawls and Branch, 1995)

• Other Physical Features
• heterothermic
• venomous

• Sexual Dimorphism
• sexes alike

• Range length

  2.0 to 3.0 m

  6.56 to 9.84 ft

• Average length

  2.2-2.7 m

  ft

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. (FitzSi­mons, 1970)

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. (FitzSi­mons, 1970; Spawls and Branch, 1995)

• 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. (FitzSi­mons, 1970; Spawls and Branch, 1995)

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

• 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

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. (FitzSi­mons, 1970)

• 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. (FitzSi­mons, 1970)

• Range lifespan
  Status: captivity

  11 (high) years

• Average lifespan
  Sex: female
  Status: captivity

  10.1 years

  Max Planck Institute for Demographic Research

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. (Branch, 1988; FitzSi­mons, 1970; Marais, 1985; Marais, 1992; Spawls and Branch, 1995)

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

Home Range

Home range sizes can vary based on habi­tat char­ac­ter­is­tics and prey den­sity. (Branch, 1988; FitzSi­mons, 1970; Marais, 1985; Marais, 1992; Spawls and Branch, 1995)

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. (Marais, 1985)

• Communication Channels
• visual
• acoustic

• Perception Channels
• visual
• tactile
• vibrations
• 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. (Branch, 1988; FitzSi­mons, 1970; Marais, 1985; Marais, 1992)

• Primary Diet
• 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. (FitzSi­mons, 1970)

• Known Predators

  • humans (Homo sapiens)
  • diurnal birds of prey (Accipitridae)
  • crocodiles (Crocodilia)
  • large frogs (Anura)
  • mongooses (Herpestes)
  • monitors (Varanus)
  • foxes and jackals (Canidae)

Ecosys­tem Roles

Very lit­tle in­for­ma­tion is avail­able on the ecosys­tem roles of black mam­bas. They are im­por­tant in con­trol­ling ro­dent pop­u­la­tions. (FitzSi­mons, 1970)

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. (FitzSi­mons, 1970)

• 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. (FitzSi­mons, 1970; Marais, 1992; Spawls and Branch, 1995)

• Negative Impacts
• injures humans
  • bites or stings
  • 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. (FitzSi­mons, 1970)

• IUCN Red List

  Least Concern
  More information

• IUCN Red List

  Least Concern
  More information

• US Federal List

  No special status

• CITES

  No special status

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. (Branch, 1988; FitzSi­mons, 1970; Marais, 1985; Marais, 1992; Spawls and Branch, 1995)

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.