The eastern green mamba (''Dendroaspis angusticeps'') is a highly
venomous snake
Venomous snakes are species of the suborder Serpentes that are capable of producing venom, which they use for killing prey, for defense, and to assist with digestion of their prey. The venom is typically delivered by injection using hollow or ...
species of the
mamba
Mambas are fast moving highly venomous snakes of the genus ''Dendroaspis'' (which literally means "tree asp") in the family Elapidae. Four extant species are recognised currently; three of those four species are essentially arboreal and green i ...
genus ''Dendroaspis'' native to the coastal regions of southern
East Africa
East Africa, Eastern Africa, or East of Africa, is the eastern subregion of the African continent. In the United Nations Statistics Division scheme of geographic regions, 10-11-(16*) territories make up Eastern Africa:
Due to the histori ...
.
Described by
Scottish
Scottish usually refers to something of, from, or related to Scotland, including:
*Scottish Gaelic, a Celtic Goidelic language of the Indo-European language family native to Scotland
*Scottish English
*Scottish national identity, the Scottish ide ...
surgeon and
zoologist
Zoology ()The pronunciation of zoology as is usually regarded as nonstandard, though it is not uncommon. is the branch of biology that studies the animal kingdom, including the structure, embryology, evolution, classification, habits, and ...
Andrew Smith in 1849, it has a slender build with a bright green back and green-yellow
ventral scales
In snakes, the ventral scales or gastrosteges are the enlarged and transversely elongated scales that extend down the underside of the body from the neck to the anal scale. When counting them, the first is the anteriormost ventral scale that conta ...
. Adult females average around in length, and males are slightly
smaller
Smaller were an English alternative rock, Britpop band from Liverpool, active during the 1990s. They had hits with "Wasted" and "Is" in 1996 and 1997.
History
The band was formed in the early 1990s by former Cook da Books guitarist/singer Pet ...
.
A shy and elusive species, the eastern green mamba is rarely seen. This elusiveness is usually attributed to its arboreal
habitat
In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...
and green colouration, which acts as
camouflage
Camouflage is the use of any combination of materials, coloration, or illumination for concealment, either by making animals or objects hard to see, or by disguising them as something else. Examples include the leopard's spotted coat, the b ...
in its natural environment. It has also been observed to use
ambush predation
Ambush predators or sit-and-wait predators are carnivorous animals that capture or trap prey via stealth, luring or by (typically instinctive) strategies utilizing an element of surprise. Unlike pursuit predators, who chase to capture prey u ...
, like many
vipers, contrary to the active foraging style typical of other
elapid
Elapidae (, commonly known as elapids ; grc, ἔλλοψ ''éllops'' "sea-fish") is a family of snakes characterized by their permanently erect fangs at the front of the mouth. Most elapids are venomous, with the exception of the genus Emydoc ...
snakes. It preys on
birds
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...
,
eggs
Humans and human ancestors have scavenged and eaten animal eggs for millions of years. Humans in Southeast Asia had domesticated chickens and harvested their eggs for food by 1,500 BCE. The most widely consumed eggs are those of fowl, especial ...
,
bats
Bats are mammals of the order Chiroptera.''cheir'', "hand" and πτερόν''pteron'', "wing". With their forelimbs adapted as wings, they are the only mammals capable of true and sustained flight. Bats are more agile in flight than most bi ...
, and rodents such as
mice
A mouse ( : mice) is a small rodent. Characteristically, mice are known to have a pointed snout, small rounded ears, a body-length scaly tail, and a high breeding rate. The best known mouse species is the common house mouse (''Mus musculus' ...
,
rats
Rats are various medium-sized, long-tailed rodents. Species of rats are found throughout the order Rodentia, but stereotypical rats are found in the genus ''Rattus''. Other rat genera include '' Neotoma'' ( pack rats), '' Bandicota'' (bandico ...
, and
gerbils.
Its
venom
Venom or zootoxin is a type of toxin produced by an animal that is actively delivered through a wound by means of a bite, sting, or similar action. The toxin is delivered through a specially evolved ''venom apparatus'', such as fangs or a ...
consists of both
neurotoxins
Neurotoxins are toxins that are destructive to nerve tissue (causing neurotoxicity). Neurotoxins are an extensive class of exogenous chemical neurological insultsSpencer 2000 that can adversely affect function in both developing and mature nerv ...
and
cardiotoxins
Cardiotoxicity is the occurrence of heart dysfunction as electric or muscle damage, resulting in heart toxicity. The heart becomes weaker and is not as efficient in pumping blood. Cardiotoxicity may be caused by chemotherapy (a usual example is th ...
. Symptoms of
envenomation
Envenomation is the process by which venom is injected by the bite or sting of a venomous animal.
Many kinds of animals, including mammals (e.g., the northern short-tailed shrew, ''Blarina brevicauda''), reptiles (e.g., the king cobra), spide ...
include swelling of the injection site, dizziness, and nausea, accompanied by difficulty breathing and swallowing, irregular heartbeat, and
convulsions
A convulsion is a medical condition where the body muscles contract and relax rapidly and repeatedly, resulting in uncontrolled shaking. Because epileptic seizures typically include convulsions, the term ''convulsion'' is sometimes used as a ...
progressing to
respiratory paralysis. Bites that result in severe envenomation can quickly be fatal.
Taxonomy
The eastern green mamba was first described as ''Naja angusticeps'' by
Andrew Smith, a
Scottish
Scottish usually refers to something of, from, or related to Scotland, including:
*Scottish Gaelic, a Celtic Goidelic language of the Indo-European language family native to Scotland
*Scottish English
*Scottish national identity, the Scottish ide ...
surgeon and zoologist, in 1849, who reported it from
Natal and east to
Maputo Bay
Maputo Bay ( pt, Baía de Maputo), formerly also known as Delagoa Bay from ''Baía da Lagoa'' in Portuguese, is an inlet of the Indian Ocean on the coast of Mozambique, between 25° 40' and 26° 20' S, with a length from north to south of over 90& ...
.
The
specific name Specific name may refer to:
* in Database management systems, a system-assigned name that is unique within a particular database
In taxonomy, either of these two meanings, each with its own set of rules:
* Specific name (botany), the two-part (bino ...
''angusticeps'' is derived from the Latin word ''angustus'', "narrow",
and ''ceps'', an abbreviated form of ''caput'' ("head") when used in a compound word. The German-British zoologist
Albert Günther
Albert Karl Ludwig Gotthilf Günther Fellow of the Royal Society, FRS, also Albert Charles Lewis Gotthilf Günther (3 October 1830 – 1 February 1914), was a German-born British zoologist, ichthyologist, and herpetologist. Günther is ranked th ...
described ''Dendroaspis intermedius'' from the
Zambezi River
The Zambezi River (also spelled Zambeze and Zambesi) is the fourth-longest river in Africa, the longest east-flowing river in Africa and the largest flowing into the Indian Ocean from Africa. Its drainage basin covers , slightly less than hal ...
in northern Mozambique in 1865. This was subsequently
synonymised with ''D. angusticeps''.
[
In 1896, the Belgian-British zoologist ]George Albert Boulenger
George Albert Boulenger (19 October 1858 – 23 November 1937) was a Belgian-British zoologist who described and gave scientific names to over 2,000 new animal species, chiefly fish, reptiles, and amphibians. Boulenger was also an active botan ...
combined the species ''Dendroaspis angusticeps'' with the black mamba
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. First formally described by Albert Günther in 1864, it is the second-longest ...
(''Dendroaspis polylepis''), a lumping
Lumpers and splitters are opposing factions in any Discipline (academia), discipline that has to place individual examples into rigorously defined Categorization, categories. The lumper–splitter problem occurs when there is the desire to create ...
diagnosis that remained in force until 1946, when the South African herpetologist
Herpetology (from Greek ἑρπετόν ''herpetón'', meaning " reptile" or "creeping animal") is the branch of zoology concerned with the study of amphibians (including frogs, toads, salamanders, newts, and caecilians (gymnophiona)) and r ...
Vivian FitzSimons published a paper after examining approximately 50 eastern green mamba and 85 black mamba specimens. He concluded that the differences in build, scalation, colouration and behaviour warranted splitting them into separate species. The British biologist Arthur Loveridge
Arthur Loveridge (28 May 1891 – 16 February 1980) was a British biologist and herpetologist who wrote about animals in East Africa, particularly Tanzania, and New Guinea. He gave scientific names to several gecko species in the region.
A ...
augmented FitzSimons' work with material from outside South Africa, noting some overlap in scalation but supporting the separation. A 2016 genetic analysis showed the eastern green and black mambas are each others' closest relatives, their common ancestor diverging from a lineage that gave rise to Jameson's mamba (''Dendroaspis jamesoni'') and the western green mamba (''Dendroaspis viridis''), as shown in the cladogram below.
As well as being called the eastern green mamba, the species is also frequently known as the common green mamba, East African green mamba, white-mouthed mamba, or simply the green mamba.
Description
The eastern green mamba is a large snake, with a slightly compressed and very slender body with a medium to long tapering tail. Adult males average around in total length, while females average . This species rarely exceeds lengths of . In general, the total length is 4–4.3 times the length of the tail. The adult eastern green mamba has bright green upperparts—occasionally with isolated yellow scales—and a pale yellow-green belly. Sometimes they are duller-coloured before moulting
In biology, moulting (British English), or molting (American English), also known as sloughing, shedding, or in many invertebrates, ecdysis, is the manner in which an animal routinely casts off a part of its body (often, but not always, an outer ...
. Juveniles are blue-green, becoming bright green when they are around long.[ The coffin-shaped head is long and slender, with a prominent ]canthus
The canthus (pl. canthi, palpebral commissures) is either corner of the eye where the upper and lower eyelids meet. More specifically, the inner and outer canthi are, respectively, the medial and lateral ends/angles of the palpebral fissure.
T ...
which is slightly demarcated from the neck.[ When threatened or otherwise aroused, the eastern green mamba is capable of flattening its neck area into a slight hood. The medium-sized eyes have round pupils,][ the borders of which have a narrow golden or ochre edge; the irises are olive green, becoming bright green posteriorly. The inside of the mouth may be white or bluish-white.]
Other green snakes are often called "green mambas" in Southern Africa
Southern Africa is the southernmost subregion of the African continent, south of the Congo and Tanzania. The physical location is the large part of Africa to the south of the extensive Congo River basin. Southern Africa is home to a number ...
, including green forms of the boomslang
The boomslang (, , or ; ''Dispholidus typus'') is a large, highly venomous snake in the family Colubridae.
Taxonomy and etymology
Its common name means "tree snake" in Afrikaans and Dutch – ''boom'' meaning "tree", and ''slang'' meaning "sn ...
(''Dispholidus typus''), which can be distinguished by their larger eyes and shorter heads. They are also venomous. Green bushsnakes of the genus '' Philothamnus''[ are also commonly confused with smaller Eastern green mambas.
]
Scalation
The number and pattern of scales on a snake's body are a key element of identification to species level. The eastern green mamba has between 17 and 21 rows of dorsal scales
In snakes, the dorsal scales are the longitudinal series of plates that encircle the body, but do not include the ventral scales. Campbell JA, Lamar WW (2004). ''The Venomous Reptiles of the Western Hemisphere''. Ithaca and London: Comstock Publis ...
at midbody, 201 to 232 ventral scales, 99 to 126 divided subcaudal scales
In snakes, the subcaudal scales are the enlarged plates on the underside of the tail.Wright AH, Wright AA. 1957. Handbook of Snakes. Comstock Publishing Associates (7th printing, 1985). 1105 pp. . These scales may be either single or divided (pair ...
, and a divided anal scale
Anal may refer to:
Related to the anus
*Related to the anus of animals:
** Anal fin, in fish anatomy
** Anal vein, in insect anatomy
** Anal scale, in reptile anatomy
*Related to the human anus:
** Anal sex, a type of sexual activity involving ...
. Its mouth is lined with 7–9 supralabial
In reptiles, the supralabial scales, also called upper-labials, are those scales that border the mouth opening along the upper jaw. They do not include the median scaleWright AH, Wright AA. 1957. Handbook of Snakes. Comstock Publishing Associates ( ...
scales above, the fourth one located under the eye, and 9–11 sublabial scale In reptiles, the sublabial scales, also called lower-labials or infralabials, are those scales that border the mouth opening along the lower jaw. They do not include the median scaleWright AH, Wright AA. 1957. ''Handbook of Snakes''. Comstock Publis ...
s below. Its eyes have three preocular and 3–5 postocular scales
In scaled reptiles, the ocular scales are those forming the margin of the eye.Wright AH, Wright AA. 1957. ''Handbook of Snakes''. Comstock Publishing Associates (7th printing, 1985). 1105 pp. . The name originates from the term ''oculus'' which ...
.
Distribution and habitat
The eastern green mamba is native to regions near the coastlines of Southern Africa
Southern Africa is the southernmost subregion of the African continent, south of the Congo and Tanzania. The physical location is the large part of Africa to the south of the extensive Congo River basin. Southern Africa is home to a number ...
and East Africa
East Africa, Eastern Africa, or East of Africa, is the eastern subregion of the African continent. In the United Nations Statistics Division scheme of geographic regions, 10-11-(16*) territories make up Eastern Africa:
Due to the histori ...
. Its range extends from Kenya
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, image_map =
, map_caption =
, image_map2 =
, capital = Nairobi
, coordinates =
, largest_city = Nairobi
, ...
south through Tanzania
Tanzania (; ), officially the United Republic of Tanzania ( sw, Jamhuri ya Muungano wa Tanzania), is a country in East Africa within the African Great Lakes region. It borders Uganda to the north; Kenya to the northeast; Comoro Islands ...
, Malawi
Malawi (; or aláwi Tumbuka: ''Malaŵi''), officially the Republic of Malawi, is a landlocked country in Southeastern Africa that was formerly known as Nyasaland. It is bordered by Zambia to the west, Tanzania to the north and northe ...
, and eastern Zimbabwe
Zimbabwe (), officially the Republic of Zimbabwe, is a landlocked country located in Southeast Africa, between the Zambezi and Limpopo Rivers, bordered by South Africa to the south, Botswana to the south-west, Zambia to the north, and Mozam ...
; it can also be found in Zanzibar
Zanzibar (; ; ) is an insular semi-autonomous province which united with Tanganyika in 1964 to form the United Republic of Tanzania. It is an archipelago in the Indian Ocean, off the coast of the mainland, and consists of many small islan ...
and northern Mozambique. An isolated and genetically distinct population is found in South Africa from the extreme northeastern part of Eastern Cape along the KwaZulu-Natal coastline and into southern Mozambique.
An elusive species, it is primarily arboreal
Arboreal locomotion is the locomotion of animals in trees. In habitats in which trees are present, animals have evolved to move in them. Some animals may scale trees only occasionally, but others are exclusively arboreal. The habitats pose num ...
(living in trees) and usually well camouflage
Camouflage is the use of any combination of materials, coloration, or illumination for concealment, either by making animals or objects hard to see, or by disguising them as something else. Examples include the leopard's spotted coat, the b ...
d in foliage. Some herpetologists
Herpetology (from Greek ἑρπετόν ''herpetón'', meaning " reptile" or "creeping animal") is the branch of zoology concerned with the study of amphibians (including frogs, toads, salamanders, newts, and caecilians (gymnophiona)) and r ...
believe its habitat is limited to tropical rainforest
Tropical rainforests are rainforests that occur in areas of tropical rainforest climate in which there is no dry season – all months have an average precipitation of at least 60 mm – and may also be referred to as ''lowland equatori ...
s in coastal lowlands. Other experts believe it can also be found in coastal bush, and dune and montane forest
Montane ecosystems are found on the slopes of mountains. The alpine climate in these regions strongly affects the ecosystem because temperatures fall as elevation increases, causing the ecosystem to stratify. This stratification is a crucia ...
. Unlike its close relative the black mamba, the eastern green mamba is rarely found in open terrain and prefers relatively dense, well-shaded vegetation. As well as wild forest habitats, it is also commonly found in thickets and farm trees such as citrus, mango, coconut, and cashew. In coastal East Africa, it is known to enter houses and may even shelter in thatched-roof dwellings. Specimens have been found at elevations up to above sea level.
Conservation status
The species' conservation status has not been assessed by the International Union for Conservation of Nature
The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natur ...
(IUCN). It is fairly common throughout its range, and populations are believed to be stable. Large concentrations of two to three individuals per hectare have been documented in coastal Kenya and southern Tanzania, and in one instance a group of five were seen in a single tree. Although populations are stable overall, habitat destruction
Habitat destruction (also termed habitat loss and habitat reduction) is the process by which a natural habitat becomes incapable of supporting its native species. The organisms that previously inhabited the site are displaced or dead, thereby ...
and deforestation
Deforestation or forest clearance is the removal of a forest or stand of trees from land that is then land conversion, converted to non-forest use. Deforestation can involve conversion of forest land to farms, ranches, or urban area, urban ...
may pose a threat.[ In South Africa, it is rated as "vulnerable" as its habitat had become highly fragmented by coastal housing development.][
]
Behaviour and ecology
A diurnal species, the eastern green mamba is active by day and sleeps at night coiled up in foliage or rarely a hollow within the trunk or branch.[ An agile snake and an adept climber, it is not commonly found on the ground though may come down to bask in the morning sun (]thermoregulation
Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different. A thermoconforming organism, by contrast, simply adopts the surrounding temperature ...
).[ A 27-day study of the movement patterns of two adults found their activity area to be relatively small, comparable to other predators who ambush prey rather than hunt (in contrast to most elapid species, including other mambas, who tend to hunt and forage). The study's preliminary evidence shed light on the species' feeding methods, suggesting it may be primarily an ambush predator due to its sit-and-wait behaviour. This evidence does not preclude active foraging, however; a specimen was also observed systematically hunting a sleeping bat.]
There is no evidence that the eastern green mamba migrates. Thought to be relatively sedentary, it can remain in the same location for days, apparently moving most commonly to find food or mates. On average, individuals move only about per day.[ They generally avoid contact with people and other predators, attacking them only if they feel threatened.]
Reproduction and lifespan
The eastern green mamba is solitary
Solitary is the state of being alone or in solitude. The term may refer to:
* shortened form of solitary confinement
* Solitary animal, an animal that does not live with others in its species
* Solitary but social, a type of social organizatio ...
except during breeding season. Gravid
In biology and human medicine, gravidity and parity are the number of times a woman is or has been pregnant (gravidity) and carried the pregnancies to a viable gestational age (parity). These terms are usually coupled, sometimes with additional t ...
females tend to be sedentary, but males actively seek and court prospective mates during the rainy season between April and June. Males have been seen engaging in agonistic behaviour; they may fight each other over mating opportunities, or possibly to establish a dominance hierarchy
In biology, a dominance hierarchy (formerly and colloquially called a pecking order) is a type of social hierarchy that arises when members of animal social groups interact, creating a ranking system. A dominant higher-ranking individual is so ...
. Typically, one male initiates a fight by moving on top of the other's body and tongue-flicking, after which the two entwine and push, attempt to pin the other's head to the ground. Male combat can last for several hours, but is less aggressive than that commonly seen in the black mamba; combatants do not bite each other.[
Males locate females by following a scent trail. The male courts the female by aligning his body along the female's while rapidly tongue-flicking. If the female is receptive to ]mating
In biology, mating is the pairing of either opposite- sex or hermaphroditic organisms for the purposes of sexual reproduction. ''Fertilization'' is the fusion of two gametes. '' Copulation'' is the union of the sex organs of two sexually rep ...
, she lifts her tail; cloacal juxtaposition follows. Courtship and mating take place in trees, after which the female can lay 4–17 eggs (10–15 on average), occurring in October and November.[ The eggs are small and elongated, usually 47–58 x 25–28 mm,][ and usually laid in leaf litter in hollow trees.][ The ]incubation period
Incubation period (also known as the latent period or latency period) is the time elapsed between exposure to a pathogenic organism, a chemical, or radiation, and when symptoms and signs are first apparent. In a typical infectious disease, the in ...
is around three months.[ When the young emerge, they are approximately ][ in the wild, and in captivity.] They usually reach adult colouration at .[ Hatchlings tend to grow to in their first year. As they age, their growth rates decrease but never completely stop.][
The oldest recorded eastern green mamba was a captive specimen that lived 18.8 years. Another captive specimen lived 14 years.]
Diet
The eastern green mamba preys primarily on bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...
s and their eggs, and small mammals including bats. It is also believed to eat arboreal lizard
Lizards are a widespread group of squamate reptiles, with over 7,000 species, ranging across all continents except Antarctica, as well as most oceanic island chains. The group is paraphyletic since it excludes the snakes and Amphisbaenia al ...
s.[ It uses a sit-and-wait strategy, though one specimen was recorded actively hunting sleeping bats.][ The species is also known to raid the nests of young birds.] Sit-and-wait tactics may be successful with highly mobile prey, such as adult birds or rodents. Documented prey include the sombre greenbul
The sombre greenbul (''Andropadus importunus'') is a member of the bulbul family of passerine birds. It is a resident breeder in coastal bush, evergreen forest and dry shrub land in eastern and southern Africa. It is the only member of the genu ...
, which occur in dense areas of natural and cultivated vegetation along Kenya's coastline. Ionides and Pitman (1965) reported a large bushveld gerbil
The bushveld gerbil (''Gerbilliscus leucogaster'') is a species of rodent found in Angola, Botswana, Democratic Republic of the Congo, Kenya, Malawi, Mozambique, Namibia, South Africa, Eswatini, Tanzania, Uganda, Zambia, and Zimbabwe. Its natural ...
in the stomach of a green mamba in Tanzania. Although the bushveld gerbil does not occur in Kenya, green mambas prey on the seven species of gerbil
The Mongolian gerbil or Mongolian jird (''Meriones unguiculatus'') is a small rodent belonging to the subfamily Gerbillinae. Their body size is typically , with a tail, and body weight , with adult males larger than females. The animal is us ...
that inhabit parts of its range.[
]
Predators
The eastern green mamba has few natural predators. Humans, mongoose
A mongoose is a small terrestrial carnivorous mammal belonging to the family Herpestidae. This family is currently split into two subfamilies, the Herpestinae and the Mungotinae. The Herpestinae comprises 23 living species that are native to ...
s, snake eagles
''Circaetus'', the snake eagles, is a genus of medium-sized eagles in the bird of prey family Accipitridae. They are mainly resident African species, but the migratory short-toed snake eagle breeds from the Mediterranean basin into Russia, the M ...
and genets commonly prey on it, and hornbill
Hornbills (Bucerotidae) are a family of bird found in tropical and subtropical Africa, Asia and Melanesia. They are characterized by a long, down-curved bill which is frequently brightly coloured and sometimes has a casque on the upper mandib ...
s and other snakes prey on juveniles.[
]
Venom
The eastern green mamba has the least toxic venom of the three green mamba species, but it is still highly venom
Venom or zootoxin is a type of toxin produced by an animal that is actively delivered through a wound by means of a bite, sting, or similar action. The toxin is delivered through a specially evolved ''venom apparatus'', such as fangs or a ...
ous. Although the most commonly encountered green mamba, it generally avoids people. The peak period for bites is the species' breeding season from September to February, during which they are most irritable. A survey in southern Africa from 1957–1979 recorded 2,553 venomous snakebites, 17 of which were confirmed as eastern green mambas. Of these 17, 10 had symptoms of systemic envenomation, though no victims died. The snake tends to bite repeatedly,[ and one bite can contain 60–95mg of ]venom
Venom or zootoxin is a type of toxin produced by an animal that is actively delivered through a wound by means of a bite, sting, or similar action. The toxin is delivered through a specially evolved ''venom apparatus'', such as fangs or a ...
by dry weight. The