Gaboon Viper

The Gaboon viper, sometimes known as the Gabon viper, is a highly poisonous, docile ground-dwelling snake found in tropical forests of western and central Africa. It is defined as the heaviest venomous snake in Africa, weighing up to 8 kg (or 18 pounds). It grows to a length of 2 metres (up to 7 feet). Also, the Gaboon viper possesses the longest gaboon viper fangs of any snake, measuring around 4 cm (or 1.6 inches) long.

The stout body can be boldly patterned with triangles and rectangles of purple, buff, and brown, which gives the snake its velvet-like appearance. This pattern provides excellent camouflage and also allows this sluggish viper (Viperidae family) to become nearly invisible among the roots and leaves of the forest floor.

Description

Typically, the gaboon adder adults are 125–155 cm (4 - 5 ft) in total length (tail and body) with a maximum total length of 205 cm (81 inches) for a specimen with the gaboon viper diet, which is collected in Sierra Leone. The sexes can be different by the length of the tail in relation to the body's total length: around 12% for males, whereas 6% for females. Adults, especially females, are stout and very heavy. One female had the dimensions as given below:

In their particular description of B. gabonica, Spawls et al. (2004) give a length of 80–130 cm (or 32.0 to 51.5 in), with the maximum total length of 175 cm (or 69.3 inches), saying the species can possibly grow larger still. They acknowledge the specimen reports over 1.8 m (6 feet), or even over 2 m (6.5 feet) in total length, but they claim no evidence supports this. A large specimen of total length 1.8 m (5.9 feet), caught in 1973, was found to weigh 11.3 kg (25 lb) with an empty stomach. In Africa, it is defined as the heaviest venomous snake.

The head is triangular and large, while the neck is greatly narrowed, almost head's one-third.[3] A pair of "horns" exists between the raised nostrils-tiny in B. gabonica. The eyes are moveable and large, set well forward, and are surrounded by 15–21 circumorbital scales. The species has 12–16 interocular scales on the top of the head. Either 4 or 5 scale rows separate the subocular and the supralabials, with the 13–18 supralabials and 16–22 sublabials. The gaboon viper fangs can reach a length up to 55 mm (or 2.2 inches), which is the longest of any venomous snake.

Midbody, which is the 28–46 dorsal scale rows, are keeled strongly except for the outer rows on every side. Slightly, the lateral scales are oblique. The ventral scales number 124–140, rarely above 132 in males, rarely less than 132 in females. With the 17–33 paired subcaudal scales, males contain no fewer than 25, and females contain no more than 23. And the anal scale is single.

In the open, the color pattern is striking, but typically, in nature, among dead leaves under trees, the camouflage lies startlingly good; in a well-kept cage with the suitable base of dried leaves, overlooking many fully exposed specimens is easy. A sequence of pale, sub-rectangular blotches run down the middle of the back, interspersed with yellow-edged, black, hourglass marks.

The flanks contain a series of brown or fawn rhomboidal shapes, with light vertical central bars. The belly looks pale with irregular black or brown blotches. The head is cream or white with a narrow, dark centre line, black dots on the back corners, and a dark blue-black triangle behind and below each eye. The iris color is yellow-white, orange, or silvery.

Behaviour

Primarily nocturnal, Gaboon vipers (with the gaboon viper diet) hold a reputation for being placid and slow-moving. Usually, they hunt by ambush, often spending long periods motionless, waiting for suitable prey to pass by, though they have been well-known to hunt actively, mostly during the night's first 6 hours. In Ghana, Kumasi, they were regularly killed by ranch hands around a few stables in an open field with the forest a few 500 m away, which is a sign that they were hunting rats in grasslands. Usually, they are very tolerant snakes, even when handled, and rarely hiss or bite, unlike most of the vipers. However, bites by bad-tempered individuals occur.

[Image will be Uploaded Soon]

Mostly, locomotion is rectilinear, in a sluggish "walking" motion of ventral scales. When alarmed, they can writhe from side to side, but only for short distances. Ditmars (of 1933) even defined them as being capable of sidewinding.

They may hiss loudly as a warning if they are threatened, doing so in a regular and deep pattern, gently flattening the head with each inhalation. Despite this, they are most unlikely to strike unless severely provoked; however, they are the fastest-striking snakes across the world, so proper care should be taken to handle them.

A number of descriptions have been given of their unaggressive nature, in general. Sweeney (1961) wrote that they are so docile, where they "can be handled as freely as any of the non-venomous species," although this is not recommended absolutely. Ionides said in Lane (1963) that he would capture specimens by softly tapping them on the top of the head initially with a tongs' pair to assess their reflexes. Anger and hissing were displayed rarely, so the tongs were usually set aside and snakes firmly grasped by the neck with one of the hands and the body supported with the other hand as he picked and carried them to a box for containment. He also said that snakes hardly ever struggled.

Parry (1975) has described how this species contains a wider range of eye movement than the other snakes. Eye movement may be maintained even if the head is rotated either up or down to an angle of up to 45° along a horizontal plane. If the head is rotated at 360°, an eye will tilt up and the other down, based on the rotation direction.

In addition, if one eye looks forward, the other eye looks back, as if both are connected to a fixed position on the axis between them. Often, in general, the eyes flick back and forth in a jerky and rapid manner. When asleep, none of the eye movement takes place and the pupils are contracted strongly. Suddenly, the pupils dilate and when the animal wakes up, the eye movement resumes.

Taxonomy

Echidna Gabonica was the name given to the Gaboon viper in 1854. Genetic differences between the two traditionally recognized subspecies of B. g. Rhinoceros and B. g. gabonica were revealed by Lenk et al. (1999). As per their research, these two subspecies are as genetically varied from each other as they came from the B. nasicornis. As a result, they classify the western variety as a different species known as B. rhinoceros.

The common names of the snakes include butterfly adder, Gaboon viper, whisper, swampjack, forest puff adder, and Gaboon adder.

Originally, a name was given by the Portuguese, which is Gabon (Gabão) that refers to the estuary, where the town of Libreville was built, in Gabon, and to a narrow strip of the territory on either bank of this sea's arm. As of 1909, Gaboon has referred to the south of the Equator and the northern portion of French Congo and lies between the Atlantic Ocean and 12°E longitude.

Distribution and Habitat

This species may be found in Ghana, Guinea, Nigeria, Togo, Cameroon, Equatorial Guinea, Gabon, DR Congo, the Republic of the Congo, northern Angola, South Sudan, Uganda, Kenya, the Central African Republic, Zambia, eastern Tanzania, eastern Zimbabwe, Malawi, Mozambique, and the northeast KwaZulu-Natal Province in South Africa. Also, Mallow et al. (2003) list Sierra Leone, Liberia in West Africa, and Senegal. The type locality can be given as "Gabon" (Africa).

The Gaboon viper is most commonly found in rainforests and surrounding woods, typically at low elevations but occasionally as high as 1500 metres above sea level. Spawls et al. (2004) has mentioned a maximum altitude of 2100 m. According to Cock and Broadley (1975), in general, it is found in environments, which are parallel to those occupied by its close relative, B. arietans, which is normally found in the more open country.

In Tanzania, this specific species can be found in cashew plantations, secondary thickets, and agricultural land under thickets and in bushes. In Uganda, they can be found in nearby grasslands and forests. Also, they do well in the reclaimed forest areas - such as coffee plantations in East Africa, cacao plantations in West Africa. Also, they have been found in evergreen forests in the Zambia region. In Zimbabwe, they only take place in areas of high rainfall along the forested escarpment in the country's east part. Generally, they can also be found in swamps and in still and moving waters as well. Commonly, they are found in agricultural areas near forests and on roads during the night.

Venom

Bites from this particular species are extremely rare because of their unaggressive nature and due to their range being limited to the rainforest areas. Because of their unwillingness and sluggishness to move even when approached, often, most bites take place because of the person accidentally stepping on a Gaboon viper, but even then, a bite will not be guaranteed. 

When a bite does take place, it should always be counted as a serious medical emergency. Also, an average bite from the average-sized specimen is potentially fatal. Antivenom must be administered very soon to save the affected limb, if not the life of the victim.