Bitis gabonica
Encyclopedia
Common names: Gaboon viper, butterfly adder, forest puff adder, swampjack, (more).

Bitis gabonica is a venomous
Venomous snake
"Poisonous snake" redirects here. For true poisonous snakes, see Rhabdophis.Venomous snakes are snakes which have venom glands and specialized teeth for the injection of venom...

 viper
Viperinae
The Viperinae, or viperines, are a subfamily of venomous vipers found in Europe, Asia and Africa. They are distinguished by their lack of the heat-sensing pit organs that characterize their sister group, the Crotalinae. Currently, 12 genera and 66 species are recognized...

 species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 found in the rainforests and savannas of Sub-Saharan Africa
Sub-Saharan Africa
Sub-Saharan Africa as a geographical term refers to the area of the African continent which lies south of the Sahara. A political definition of Sub-Saharan Africa, instead, covers all African countries which are fully or partially located south of the Sahara...

. This is not only the largest member of the genus
Bitis
Bitis
Bitis is a genus of venomous vipers found in Africa and the southern Arabian Peninsula. It includes the largest and the smallest vipers in the world. Members are known for their characteristic threat displays that involves inflating and deflating their bodies while hissing and puffing loudly. The...

, but also the world's heaviest viperid
Viperidae
The Viperidae are a family of venomous snakes found all over the world, except in Antarctica, Australia, Ireland, Madagascar, Hawaii, various other isolated islands, and above the Arctic Circle. All have relatively long, hinged fangs that permit deep penetration and injection of venom. Four...

 and it has the longest fangs (up to 2 inches),and the highest venom yield of any venomous snake. Two subspecies are currently recognized, including the nominate race described here.

Description

Adults average 122–152 cm (4 to 5 feet) in length with a maximum of 205 cm (81 in) for a specimen collected in Sierra Leone
Sierra Leone
Sierra Leone , officially the Republic of Sierra Leone, is a country in West Africa. It is bordered by Guinea to the north and east, Liberia to the southeast, and the Atlantic Ocean to the west and southwest. Sierra Leone covers a total area of and has an estimated population between 5.4 and 6.4...

. The sexes may be distinguished by the length of the tail in relation to the total length of the body: approximately 12% for males and 6% for females. Adults, especially females, are very heavy and stout. One female had the following dimensions:

Total length 174 cm (69 in)
Head width 12 cm (4.7 in)
Girth
Girth
In graph theory, the girth of a graph is the length of a shortest cycle contained in the graph. If the graph does not contain any cycles , its girth is defined to be infinity....

37 cm (14.65 in)
Weight (empty stomach) 8.5 kg (19 lbs)



In their description of B. gabonica, Spawls et al.. (2004) give an average length of 80–130 cm (32 to 51.5 in), with a maximum size of 175 cm (69.3 in), saying the species may possibly grow larger still. They acknowledge reports of specimens over 6 feet (1.8 m), or even over 2 m (6.5 ft) in length, but claim there is no evidence to support this.

The head is large and triangular, while the neck is greatly narrowed: almost one-third the width of the head. A pair of horns is present between the raised nostrils — tiny in B. g. gabonica, but much larger in B. g. rhinoceros
Bitis gabonica rhinoceros
Bitis gabonica rhinoceros is a venomous viper subspecies found in West Africa. It is distinguished from the nominate subspecies primarily by the presence of a set of large nasal horns.-Description:...

. The eyes are large and moveable, set well forward, and surrounded by 15–21 circumorbital scales. There are 12–16 interocular scales across the top of the head. 4–5 scale rows separate the suboculars and the supralabials. There are 13–18 supralabials and 16–22 sublabials. The fangs may reach a length of 55 millimetres (2.2 in) : the longest of any venomous snake.

Midbody, there are 28–46 dorsal scale rows, all of which are strongly keeled except for the outer rows on each side. The lateral scales are slightly oblique. The ventral scales
Ventral scales
In snakes, the ventral scales 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 contacts the paraventral row of dorsal scales on either side...

 number 124–140: rarely more than 132 in males, rarely less than 132 in females. There are 17–33 paired subcaudal scales
Subcaudal scales
In snakes, the subcaudal scales are the enlarged plates on the underside of the tail. These scales may be either single or divided and are preceded by the anal scale....

: males have no fewer than 25, females no more than 23. The anal scale
Anal scale
In snakes, the anal scale is the scale just in front of and covering the cloacal opening. This scale can be either single or paired . When paired, the division is oblique. It is preceded by the ventral scales and followed by the subcaudal scales....

 is single.

The color pattern consists of a series of pale, sub-rectangular blotches running down the center of the back, interspaced with dark, yellow-edged hourglass markings. The flanks have a series of fawn of brown rhomboidal shapes, with light vertical central bars. The belly is pale with irregular brown or black blotches. The head is white or cream with a fine, dark central line, black spots on the rear corners, and a dark blue-black triangle behind and below each eye. The iris color is cream, yellow-white, orange or silvery.

Common names

Gaboon viper, butterfly adder, forest puff adder, swampjack, Gaboon adder, Gabon viper.

Originally a name given by the Portuguese
Portugal
Portugal , officially the Portuguese Republic is a country situated in southwestern Europe on the Iberian Peninsula. Portugal is the westernmost country of Europe, and is bordered by the Atlantic Ocean to the West and South and by Spain to the North and East. The Atlantic archipelagos of the...

, Gabon (Gabão) refers to the estuary on which the town of Libreville
Libreville
Libreville is the capital and largest city of Gabon, in west central Africa. The city is a port on the Komo River, near the Gulf of Guinea, and a trade center for a timber region. As of 2005, it has a population of 578,156.- History :...

 was built, in Gabon
Gabon
Gabon , officially the Gabonese Republic is a state in west central Africa sharing borders with Equatorial Guinea to the northwest, Cameroon to the north, and with the Republic of the Congo curving around the east and south. The Gulf of Guinea, an arm of the Atlantic Ocean is to the west...

, and to a narrow strip of territory on either bank of this arm of the sea. As of 1909,
Gaboon referred to the northern portion of French Congo
French Congo
The French Congo was a French colony which at one time comprised the present-day area of the Republic of the Congo, Gabon, and the Central African Republic...

, south of the Equator and lying between the Atlantic Ocean
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...

 and 12° east longitude.

Geographic range

This species can be found in Guinea
Guinea
Guinea , officially the Republic of Guinea , is a country in West Africa. Formerly known as French Guinea , it is today sometimes called Guinea-Conakry to distinguish it from its neighbour Guinea-Bissau. Guinea is divided into eight administrative regions and subdivided into thirty-three prefectures...

, Ghana
Ghana
Ghana , officially the Republic of Ghana, is a country located in West Africa. It is bordered by Côte d'Ivoire to the west, Burkina Faso to the north, Togo to the east, and the Gulf of Guinea to the south...

, Togo
Togo
Togo, officially the Togolese Republic , is a country in West Africa bordered by Ghana to the west, Benin to the east and Burkina Faso to the north. It extends south to the Gulf of Guinea, on which the capital Lomé is located. Togo covers an area of approximately with a population of approximately...

, Nigeria
Nigeria
Nigeria , officially the Federal Republic of Nigeria, is a federal constitutional republic comprising 36 states and its Federal Capital Territory, Abuja. The country is located in West Africa and shares land borders with the Republic of Benin in the west, Chad and Cameroon in the east, and Niger in...

, Cameroon
Cameroon
Cameroon, officially the Republic of Cameroon , is a country in west Central Africa. It is bordered by Nigeria to the west; Chad to the northeast; the Central African Republic to the east; and Equatorial Guinea, Gabon, and the Republic of the Congo to the south. Cameroon's coastline lies on the...

, DR Congo
Democratic Republic of the Congo
The Democratic Republic of the Congo is a state located in Central Africa. It is the second largest country in Africa by area and the eleventh largest in the world...

, Central African Republic
Central African Republic
The Central African Republic , is a landlocked country in Central Africa. It borders Chad in the north, Sudan in the north east, South Sudan in the east, the Democratic Republic of the Congo and the Republic of the Congo in the south, and Cameroon in the west. The CAR covers a land area of about ,...

, southern Sudan
Sudan
Sudan , officially the Republic of the Sudan , is a country in North Africa, sometimes considered part of the Middle East politically. It is bordered by Egypt to the north, the Red Sea to the northeast, Eritrea and Ethiopia to the east, South Sudan to the south, the Central African Republic to the...

, Uganda
Uganda
Uganda , officially the Republic of Uganda, is a landlocked country in East Africa. Uganda is also known as the "Pearl of Africa". It is bordered on the east by Kenya, on the north by South Sudan, on the west by the Democratic Republic of the Congo, on the southwest by Rwanda, and on the south by...

, Kenya
Kenya
Kenya , officially known as the Republic of Kenya, is a country in East Africa that lies on the equator, with the Indian Ocean to its south-east...

, eastern Tanzania
Tanzania
The United Republic of Tanzania is a country in East Africa bordered by Kenya and Uganda to the north, Rwanda, Burundi, and the Democratic Republic of the Congo to the west, and Zambia, Malawi, and Mozambique to the south. The country's eastern borders lie on the Indian Ocean.Tanzania is a state...

, Zambia
Zambia
Zambia , officially the Republic of Zambia, is a landlocked country in Southern Africa. The neighbouring countries are the Democratic Republic of the Congo to the north, Tanzania to the north-east, Malawi to the east, Mozambique, Zimbabwe, Botswana and Namibia to the south, and Angola to the west....

, Malawi
Malawi
The Republic of Malawi is a landlocked country in southeast Africa that was formerly known as Nyasaland. It is bordered by Zambia to the northwest, Tanzania to the northeast, and Mozambique on the east, south and west. The country is separated from Tanzania and Mozambique by Lake Malawi. Its size...

, eastern Zimbabwe
Zimbabwe
Zimbabwe is a landlocked country located in the southern part of the African continent, between the Zambezi and Limpopo rivers. It is bordered by South Africa to the south, Botswana to the southwest, Zambia and a tip of Namibia to the northwest and Mozambique to the east. Zimbabwe has three...

, Mozambique
Mozambique
Mozambique, officially the Republic of Mozambique , is a country in southeastern Africa bordered by the Indian Ocean to the east, Tanzania to the north, Malawi and Zambia to the northwest, Zimbabwe to the west and Swaziland and South Africa to the southwest...

, northeast KwaZulu-Natal Province
KwaZulu-Natal
KwaZulu-Natal is a province of South Africa. Prior to 1994, the territory now known as KwaZulu-Natal was made up of the province of Natal and the homeland of KwaZulu....

 in South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...

. Mallow
et al. (2003) also list Sierra Leone
Sierra Leone
Sierra Leone , officially the Republic of Sierra Leone, is a country in West Africa. It is bordered by Guinea to the north and east, Liberia to the southeast, and the Atlantic Ocean to the west and southwest. Sierra Leone covers a total area of and has an estimated population between 5.4 and 6.4...

 and Liberia
Liberia
Liberia , officially the Republic of Liberia, is a country in West Africa. It is bordered by Sierra Leone on the west, Guinea on the north and Côte d'Ivoire on the east. Liberia's coastline is composed of mostly mangrove forests while the more sparsely populated inland consists of forests that open...

 in West Africa
West Africa
West Africa or Western Africa is the westernmost region of the African continent. Geopolitically, the UN definition of Western Africa includes the following 16 countries and an area of approximately 5 million square km:-Flags of West Africa:...

. The type locality is given as "Gabon
Gabon
Gabon , officially the Gabonese Republic is a state in west central Africa sharing borders with Equatorial Guinea to the northwest, Cameroon to the north, and with the Republic of the Congo curving around the east and south. The Gulf of Guinea, an arm of the Atlantic Ocean is to the west...

" (Africa).

Habitat

The Gaboon viper is usually found in rainforests and nearby woodlands, mainly at low altitudes, but sometimes as high as 1500 m. Spawls
et al. (2004) mention a maximum altitude of 2100 m. According to Broadley and Cook (1975), it is generally found in environments that are parallel to those occupied by its close relative, B. arietans
Bitis arietans
Bitis arietans is a venomous viper species found in savannah and grasslands from Morocco and western Arabia throughout Africa except for the Sahara and rain forest regions. It is responsible for causing the most fatalities in Africa owing to various factors, such as its wide distribution and...

, which is normally found in more open country.

In Tanzania
Tanzania
The United Republic of Tanzania is a country in East Africa bordered by Kenya and Uganda to the north, Rwanda, Burundi, and the Democratic Republic of the Congo to the west, and Zambia, Malawi, and Mozambique to the south. The country's eastern borders lie on the Indian Ocean.Tanzania is a state...

, this species is found in secondary thickets, cashew plantations, and in agricultural land under bushes and in thickets. In Uganda
Uganda
Uganda , officially the Republic of Uganda, is a landlocked country in East Africa. Uganda is also known as the "Pearl of Africa". It is bordered on the east by Kenya, on the north by South Sudan, on the west by the Democratic Republic of the Congo, on the southwest by Rwanda, and on the south by...

, they are found in forests and nearby grasslands. They also do well in reclaimed forest areas: cacao plantations in West Africa
West Africa
West Africa or Western Africa is the westernmost region of the African continent. Geopolitically, the UN definition of Western Africa includes the following 16 countries and an area of approximately 5 million square km:-Flags of West Africa:...

 and coffee plantations in East Africa
East Africa
East Africa or Eastern Africa is the easterly region of the African continent, variably defined by geography or geopolitics. In the UN scheme of geographic regions, 19 territories constitute Eastern Africa:...

. They have been found in evergreen forests in Zambia
Zambia
Zambia , officially the Republic of Zambia, is a landlocked country in Southern Africa. The neighbouring countries are the Democratic Republic of the Congo to the north, Tanzania to the north-east, Malawi to the east, Mozambique, Zimbabwe, Botswana and Namibia to the south, and Angola to the west....

. In Zimbabwe
Zimbabwe
Zimbabwe is a landlocked country located in the southern part of the African continent, between the Zambezi and Limpopo rivers. It is bordered by South Africa to the south, Botswana to the southwest, Zambia and a tip of Namibia to the northwest and Mozambique to the east. Zimbabwe has three...

, they only occur in areas of high rainfall along the forested escarpment in the east of the country. In general they may also be found in swamps, as well as in still and moving waters. They are commonly found in agricultural areas near forests and on roads at night.

Behavior

Primarily nocturnal, Gaboon vipers have a reputation for being slow-moving and placid. They usually hunt by ambush, often spending long periods motionless, waiting for suitable prey to happen by. On the other hand, they have been known to hunt actively, mostly during the first six hours of the night. In Kumasi, Ghana
Ghana
Ghana , officially the Republic of Ghana, is a country located in West Africa. It is bordered by Côte d'Ivoire to the west, Burkina Faso to the north, Togo to the east, and the Gulf of Guinea to the south...

, they were regularly killed around some stables in an open area with the forest some 500 meters away — a sign that they were hunting rats in the grassland. They are usually very tolerant snakes, even when handled, and rarely bite or hiss, unlike most vipers. However, bites by bad-tempered individuals do occur.
Locomotion is mostly rectilinear, in a sluggish "walking" motion of the ventral scales. They may writhe from side to side when alarmed, but only for short distances. Ditmars
Raymond Ditmars
Raymond Lee Ditmars was an American herpetologist.Ditmars was very interested in animals, , obtaining his first snakes at twelve years of age...

 (1933) even described them as being capable of sidewinding
Sidewinding
Sidewinding is a type of locomotion unique to caenophidian snakes, used to move across loose or slippery substrates. It is most often used by the Saharan horned viper, Cerastes cerastes, and the sidewinder rattlesnake, Crotalus cerastes, to move across loose desert sands, but it is also used by...

.

If threatened, they may hiss loudly as a warning, doing so in a deep and steady rhythm, slightly flattening the head at the expiration of each breath. Despite this, they are unlikely to strike unless severely provoked.

There have been numerous descriptions of their generally unaggressive nature. Sweeney (1961) wrote that they are so docile that they "can be handled as freely as any non-venomous species", although this is absolutely not recommended. In Lane (1963), Ionides explains that he would capture specimens by first touching them lightly on the top of the head with a pair of tongs to test its reaction. Anger was rarely displayed, so the tongs were usually set aside and the snake firmly grasped by the neck with one hand and the body supported with the other as he picked it up and carried it to a box for containment. He said the snakes hardly ever struggled.

Parry (1975) describes how this species has a wider range of eye movement than other snakes. Along a horizontal plane, eye movement can be maintained even if the head is rotated up or down to an angle of up to 45°. If the head is rotated 360°, one eye will tilt up and the other down, depending on the direction of rotation. Also, if one eye looks forwards the other looks back, as if both are connected to a fixed position on an axis between them. In general, the eyes often flick back and forth in a rapid and jerky manner. When asleep, there is no eye movement and the pupils are strongly contracted. The pupils dilate suddenly and eye movement resumes when the animal wakes up.

Feeding

Because of their large heavyset size, the adults have no trouble eating prey as large as fully-grown rabbits. When prey happens by, they strike with very fast precision from any angle. Once they strike their prey, they hang on to it with their large fangs rather than letting it go and waiting for it to die. This behavior is very different from the behavior of other species of vipers. These snakes feed on a variety of birds and mammals, such as doves, many different species of rodents, including field mice and rats, as well as hares and rabbits. There are also reports of more unlikely prey items, such as tree monkeys, the brush-tailed porcupine (Atherurus) and even the small royal antelope
Royal Antelope
The Royal Antelope is a West African antelope, only 25–30 cm high at the shoulder and weighing only 3.2–3.6 kg — it is the smallest of all antelopes. Their calves are small enough to fit into the average person's open hand...

 (Neotragus).

Reproduction

During peak sexual activity, males engage in combat. This starts with one male rubbing its chin along the back of the other. The second male will then raise its head as high as possible. As they both do the same, the necks intertwine. When the heads are level, they turn towards each other and push. Their bodies intertwine as they switch positions. They become oblivious to everything else, continuing even after they fall off a surface or into water. Sometimes they intertwine and squeeze so tightly that their scales stand out from the pressure. They have also been observed to strike at each other with mouths closed. Occasionally, the combatants will tire and break off the fight by "mutual consent", resting for a while before resuming once more. The event is settled when one of the two succeeds in pushing the other's head to the ground and raising its own by 20–30 cm. In captivity, combat may occur 4–5 times a week until courtship and copulation ends.

Gestation takes about a year, which suggests a breeding cycle of 2–3 years. A 5-year breeding cycle may also be possible. Usually, they give birth in late summer. B. g. gabonica produces 8–43 live young. B. g. rhinoceros
Bitis gabonica rhinoceros
Bitis gabonica rhinoceros is a venomous viper subspecies found in West Africa. It is distinguished from the nominate subspecies primarily by the presence of a set of large nasal horns.-Description:...

may produce as many as 60. However, the actual number of offspring rarely exceeds 24. Neonates are 25–32 cm in length and weigh 25–45 g.

Venom

Bites are relatively rare, due to their docile nature and the fact that their range is mainly limited to rainforest areas. Due to their sluggishness and unwillingness to move even when approached, people are often bitten after they accidentally step on them, but even then in some cases they may not bite. However, when a bite does occur it should always be considered a serious medical emergency
Medical emergency
A medical emergency is an injury or illness that is acute and poses an immediate risk to a person's life or long term health. These emergencies may require assistance from another person, who should ideally be suitably qualified to do so, although some of these emergencies can be dealt with by the...

. Even an average bite from an average sized specimen is potentially fatal. Antivenom should be administered as soon as possible to save the victim's life if not the affected limb.

The snake's hemotoxic venom itself is not considered particularly toxic based on tests conducted in mice. In mice, the is 0.8–5.0 mg/kg IV
Intravenous therapy
Intravenous therapy or IV therapy is the infusion of liquid substances directly into a vein. The word intravenous simply means "within a vein". Therapies administered intravenously are often called specialty pharmaceuticals...

, 2.0 mg/kg IP and 5.0–6.0 mg/kg SC. However, the venom glands are enormous and each bite produces the largest quantities of venom of any venomous snake
Venomous snake
"Poisonous snake" redirects here. For true poisonous snakes, see Rhabdophis.Venomous snakes are snakes which have venom glands and specialized teeth for the injection of venom...

. Yield is probably related to body weight, as opposed to milking interval. Brown (1973) gives a venom yield range of 200–1000 mg (of dried venom), A range of 200–600 mg for specimens 125–155 cm in length has also been reported. Spawls and Branch (1995) state that from 5 to 7 ml (450–600 mg) of venom may be injected in a single bite.

A study by Marsh and Whaler (1984) reported a maximum yield of 9.7 ml of wet venom, which translated to 2400 mg of dried venom. They attached "alligator" clip electrodes
Crocodile clip
thumb|Standard clipthumb|Pair of standard clipsA crocodile clip is a simple mechanical device for creating a temporary electrical connector, and is named for its resemblance to an alligator's or crocodile's jaws...

 to the angle of the open jaw of anesthetized
Anesthesia
Anesthesia, or anaesthesia , traditionally meant the condition of having sensation blocked or temporarily taken away...

 specimens (length 133–136 cm, girth 23–25 cm, weight 1.3–3.4 kg), yielding 1.3–7.6 ml (mean 4.4 ml) of venom. Two to three electrical bursts within a space of five seconds apart were enough to empty the venom glands. The snakes used for the study were milked 7 to 11 times over a 12-month period, during which they remained in good health and the potency of their venom remained the same.

Based on how sensitive monkey
Monkey
A monkey is a primate, either an Old World monkey or a New World monkey. There are about 260 known living species of monkey. Many are arboreal, although there are species that live primarily on the ground, such as baboons. Monkeys are generally considered to be intelligent. Unlike apes, monkeys...

s were to the venom, Whaler (1971) estimated that 14 mg of venom would be enough to kill a human being: equivalent to 0.06 ml of venom, or 1/50–1/1000 of what can be obtained in a single milking. Marsh and Whaler (1984) wrote that 35 mg (1/30 of the average venom yield) would be enough to kill a man of 70 kilograms (154.3 lb). Branch (1992) suggested that 90–100 mg would be fatal in humans. Further investigation is needed.

In humans, a bite causes rapid and conspicuous swelling
Swelling (medical)
In medical parlance, swelling is the transient enlargement or protuberance in the body and may include tumors. According to cause, it may be congenital, traumatic, inflammatory, neoplastic or miscellaneous....

, intense pain
Pain
Pain is an unpleasant sensation often caused by intense or damaging stimuli such as stubbing a toe, burning a finger, putting iodine on a cut, and bumping the "funny bone."...

, severe shock and local blister
Blister
A blister is a small pocket of fluid within the upper layers of the skin, typically caused by forceful rubbing , burning, freezing, chemical exposure or infection. Most blisters are filled with a clear fluid called serum or plasma...

ing. Other symptoms may include uncoordinated movements, defecation
Defecation
Defecation is the final act of digestion by which organisms eliminate solid, semisolid or liquid waste material from the digestive tract via the anus. Waves of muscular contraction known as peristalsis in the walls of the colon move fecal matter through the digestive tract towards the rectum...

, urination
Urination
Urination, also known as micturition, voiding, peeing, weeing, pissing, and more rarely, emiction, is the ejection of urine from the urinary bladder through the urethra to the outside of the body. In healthy humans the process of urination is under voluntary control...

, swelling of the tongue and eyelids, convulsions
Seizure
An epileptic seizure, occasionally referred to as a fit, is defined as a transient symptom of "abnormal excessive or synchronous neuronal activity in the brain". The outward effect can be as dramatic as a wild thrashing movement or as mild as a brief loss of awareness...

 and unconsciousness
Unconsciousness
Unconsciousness is the condition of being not conscious—in a mental state that involves complete or near-complete lack of responsiveness to people and other environmental stimuli. Being in a comatose state or coma is a type of unconsciousness. Fainting due to a drop in blood pressure and a...

. Blistering, bruising
Bruise
A bruise, also called a contusion, is a type of relatively minor hematoma of tissue in which capillaries and sometimes venules are damaged by trauma, allowing blood to seep into the surrounding interstitial tissues. Bruises can involve capillaries at the level of skin, subcutaneous tissue, muscle,...

 and necrosis
Necrosis
Necrosis is the premature death of cells in living tissue. Necrosis is caused by factors external to the cell or tissue, such as infection, toxins, or trauma. This is in contrast to apoptosis, which is a naturally occurring cause of cellular death...

 may be extensive. There may be sudden hypotension
Hypotension
In physiology and medicine, hypotension is abnormally low blood pressure, especially in the arteries of the systemic circulation. It is best understood as a physiologic state, rather than a disease. It is often associated with shock, though not necessarily indicative of it. Hypotension is the...

, heart damage and dyspnoea
Dyspnea
Dyspnea , shortness of breath , or air hunger, is the subjective symptom of breathlessness.It is a normal symptom of heavy exertion but becomes pathological if it occurs in unexpected situations...

. The blood may become incoagulable with internal bleeding that may lead to haematuria and haematemesis. Local tissue damage may require surgical excision
Surgery
Surgery is an ancient medical specialty that uses operative manual and instrumental techniques on a patient to investigate and/or treat a pathological condition such as disease or injury, or to help improve bodily function or appearance.An act of performing surgery may be called a surgical...

 and possibly amputation
Amputation
Amputation is the removal of a body extremity by trauma, prolonged constriction, or surgery. As a surgical measure, it is used to control pain or a disease process in the affected limb, such as malignancy or gangrene. In some cases, it is carried out on individuals as a preventative surgery for...

. Healing may be slow and fatalities during the recovery period are not uncommon.

Subspecies

Subspecies Taxon author Common name Geographic range
B. g. gabonica (Duméril
André Marie Constant Duméril
André Marie Constant Duméril was a French zoologist. He was professor of anatomy at the Muséum National d'Histoire Naturelle from 1801 to 1812, when he became professor of herpetology and ichthyology...

, Bibron
Gabriel Bibron
Gabriel Bibron was a French zoologist. He was born in Paris. Son of an employee of the Museum national d'histoire naturelle, he had a good foundation in natural history and was hired to collect vertebrates in Italy and Sicily. He classified a number of reptile species with André Marie Constant...

 & Duméril
Auguste Duméril
Auguste Henri André Duméril was a French zoologist. He was professor of Herpetology and Ichthyology at the Muséum National d'Histoire Naturelle in Paris from 1857. His father André Marie Constant Duméril was also a zoologist...

, 1854)
East African Gaboon viper Central, eastern and southern Africa.
B. g. rhinoceros
Bitis gabonica rhinoceros
Bitis gabonica rhinoceros is a venomous viper subspecies found in West Africa. It is distinguished from the nominate subspecies primarily by the presence of a set of large nasal horns.-Description:...

(Schlegel
Hermann Schlegel
Hermann Schlegel was a German ornithologist and herpetologist.-Early life and education:Schlegel was born at Altenburg, the son of a brassfounder. His father collected butterflies, which stimulated Schlegel's interest in natural history...

, 1855)
West African Gaboon viper West Africa.

Taxonomy

Lenk et al. (1999) discovered considerable differences between the two conventionally recognized subspecies of B. gabonica described above. According to their research, these two subspecies are as different from each other as they are from B. nasicornis
Bitis nasicornis
Bitis nasicornis is a venomous viper species found in the forests of West and Central Africa. A big viper known for its striking color pattern and prominent horns on its nose. No subspecies are recognized.-Description:...

. Consequently, Lenk et al. (1999) regard the western form as a separate species, B. rhinoceros.

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK