Gaboon vipers have a restricted range and are essentially forest dwellers. They are very spectacular being the heaviest, if not the longest venomous snake in Africa and one of the largest venomous snakes in the world.
In Zimbabwe, they are found only along the eastern border, mainly in the river valleys i.e. Honde valley, Burma valley, Pungwe valley, Lisitu valley but also Mt. Selinda, and extending into Mozambique. In South Africa they are restricted to the forests of northern Zululand between Matubatuba and St. Lucia. Elsewhere in Africa they are found in tropical forests throughout Zaire, northern Angola, Zambia, south eastern Tanzania, western Kenya, Uganda and from southern Sudan to Guinea.
Their camouflage is remarkable and they become almost invisible in leaf litter and dappled sunlight on the forest floor. Average size is about 1,2m but they can get up to 1,8m. In West Africa they have been found over two meters, weighing over 8,5kg! The head can be over 125mm across and the fangs up to 50mm in length.
They have a very high venom yield, which is not exceptionally toxic, but would invariably be fatal to man purely because of the amount they can inject through their super efficient-fangs. The strike is so fast that it is invisible to the naked eye! The good news is that they are docile snakes and seldom bite, even when stood on. Hundreds of these snakes have been found in the Aberfoyle tea estates in the Honde Valley since they were established in the early 1950’s.
But there is no record of anyone being bitten – remarkable, because the tea pickers locate them by standing on or next to them, when they will make a loud explosive hissing noise. Tea bushes are thick and it is not possible for the pickers to see where they are putting their feet.
Gaboon vipers do well in captivity and are very undemanding. They are bred successfully in the USA and Europe where, being ideally suited because of their high venom yield, they are milked to make serum and other medical products. They are not common and are especially protected in South Africa to prevent them being exploited for their skins.
Some years ago an application was made to the Department Of National Parks and Wildlife Management in Harare for a permit to sell snakeskin hand-bags and shoes. The applicant claimed that the leather had come from Gaboon vipers that had been culled in Botswana! Had they said anywhere other than Botswana they may have got their permit (there are no forests or Gaboons in Botswana). The skins were actually identified as python skins by the small scales and pattern which could just be seen under the dye. A hefty fine was imposed, justifiably!
Male combat has been observed in captivity – something seldom seen in other species. The dominant male gets to mate with the female and live young are born up to 12 months later. The average number of young is 20 – 40 in southern African snakes, but can be up to 60 in the West African species. The neonates are highly venomous when born and are far more likely to bite than the adults.