Gaboon viper

Description

The Gaboon viper (Bitis gabonica) is a viper species found in the rainforests and savannas of sub-Saharan Africa.Like all vipers, it is venomous. It is the largest member of the genus Bitis,and it has the longest fangs of any venomous snake – up to 2 inches (5 cm) in length – and the highest venom yield of any snake. No subspecies are recognized. Adults are typically 125–155 cm (4 to 5 ft) in total length (body and tail) with a maximum total length of 205 cm (81 in) for a specimen collected in Sierra Leone. The sexes may be distinguished by the length of the tail in relation to the total length of the body: around 12% for males and 6% for females. Adults, especially females, are very heavy and stout. One female had these dimensions: In their description of B. gabonica, Spawls et al. (2004) give a total length of 80–130 cm (32.0 to 51.5 in), with a maximum total length of 175 cm (69.3 in), saying the species may possibly grow larger still. They acknowledge reports of specimens over 1.8 m (6 ft), or even over 2 m (6.5 ft) in total length, but claim no evidence supports this.A large specimen of 1.8 m (5.9 ft) total length, caught in 1973, was found to have weighed 11.3 kg (25 lb) with an empty stomach.It is the heaviest venomous snake in Africa. The head is large and triangular, while the neck is greatly narrowed, only about one-third the width of the head. A pair of "horns" is present between the raised nostrils—tiny in B. gabonica.The eyes are large and moveable, set well forward, and surrounded by 15–21 circumorbital scales.The species has 12–16 interocular scales across the top of the head. Four or five scale rows separate the suboculars and the supralabials, with 13–18 supralabials and 16–22 sublabials. The fangs may reach a length of 55 mm (2.2 in), the longest of any venomous snake. Midbody, the 28–46 dorsal scale rows are strongly keeled except for the outer rows on each side. The lateral scales are slightly oblique. The ventral scales number 124–140, rarely more than 132 in males, rarely less than 132 in females. With 17–33 paired subcaudal scales, males have no fewer than 25, and females no more than 23. The anal scale is single.