Bitis atropos
Encyclopedia
- Common names: berg adder, Cape mountain adder, mountain adder.
Bitis atropos 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 only in mountainous regions in southern Africa
Southern Africa
Southern Africa is the southernmost region of the African continent, variably defined by geography or geopolitics. Within the region are numerous territories, including the Republic of South Africa ; nowadays, the simpler term South Africa is generally reserved for the country in English.-UN...
. A small species. No subspecies are currently recognized.
Description
Geographic range
The species is found in isolated populations of the mountainous regions of southern AfricaSouthern Africa
Southern Africa is the southernmost region of the African continent, variably defined by geography or geopolitics. Within the region are numerous territories, including the Republic of South Africa ; nowadays, the simpler term South Africa is generally reserved for the country in English.-UN...
. 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...
, the species is known to occur in the Transvaal
Transvaal Province
Transvaal Province was a province of the Union of South Africa from 1910 to 1961, and of its successor, the Republic of South Africa, from 1961 until the end of apartheid in 1994 when a new constitution subdivided it.-History:...
, along the Drakensberg escarpment
Drakensberg
The Drakensberg is the highest mountain range in Southern Africa, rising to in height. In Zulu, it is referred to as uKhahlamba , and in Sesotho as Maluti...
of the eastern and northern Transvaal. Elsewhere in South Africa, it occurs in western Natal
Natal Province
Natal, meaning "Christmas" in Portuguese, was a province of South Africa from 1910 until 1994. Its capital was Pietermaritzburg. The Natal Province included the bantustan of KwaZulu...
, Lesotho
Lesotho
Lesotho , officially the Kingdom of Lesotho, is a landlocked country and enclave, surrounded by the Republic of South Africa. It is just over in size with a population of approximately 2,067,000. Its capital and largest city is Maseru. Lesotho is a member of the Commonwealth of Nations. The name...
and eastern Free State
Free State
The Free State is a province of South Africa. Its capital is Bloemfontein, which is also South Africa's judicial capital. Its historical origins lie in the Orange Free State Boer republic and later Orange Free State Province. The current borders of the province date from 1994 when the Bantustans...
, and in the southern coastal mountains of western and eastern Cape Province
Cape Province
The Province of the Cape of Good Hope was a province in the Union of South Africa and subsequently the Republic of South Africa...
. Spawls & Branch (1995) also mention that in Cape Province, its range extends into the Cape Peninsula
Cape Peninsula
The Cape Peninsula is a generally rocky peninsula that juts out for 75 km into the Atlantic Ocean at the south-western extremity of the African continent. At the southern end of the peninsula are Cape Point and the Cape of Good Hope...
. It also occurs in Swaziland
Swaziland
Swaziland, officially the Kingdom of Swaziland , and sometimes called Ngwane or Swatini, is a landlocked country in Southern Africa, bordered to the north, south and west by South Africa, and to the east by Mozambique...
, in higher altitudes of 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...
like the Inyanga Highlands and Chimanimani Mountains
Chimanimani, Zimbabwe
Chimanimani is a mountainous area in the province of Manicaland, eastern Zimbabwe. The region is distinguished by large peaks,carved from a rifted quartzite block, the highest reaching to 2440 m and stretching for some 50 km , forming the border with Mozambique...
and in nearby 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...
.
The type locality given is "America", but this is obviously a mistake. More likely is the Cape of Good Hope
Cape of Good Hope
The Cape of Good Hope is a rocky headland on the Atlantic coast of the Cape Peninsula, South Africa.There is a misconception that the Cape of Good Hope is the southern tip of Africa, because it was once believed to be the dividing point between the Atlantic and Indian Oceans. In fact, the...
, according to FitzSimons (1962).
Habitat
Occupies a number of different habitats, but prefers relatively cool environments with high levels of precipitation. In the northern part of its range, where the winters are cold and dry and the summers warm and wet, it is therefore restricted to higher elevations, up to 3000 m. In Zimbabwe, it is not found below 1500 m. Usually associated with mountain slopes and rocky hillsides, but also montane grassland with patches of bushes and shrubs.In the southern part of its range (Cape Province, South Africa), where the winters are cold and wet and the summers warm and dry, it can be found in coastal and mountain heathland as well as small rock outcrops at sea level and grassy areas with clumps of bushes and shrubs west of the Cape Peninsula
Cape Peninsula
The Cape Peninsula is a generally rocky peninsula that juts out for 75 km into the Atlantic Ocean at the south-western extremity of the African continent. At the southern end of the peninsula are Cape Point and the Cape of Good Hope...
.
Food and venom
The Berg adder is unusual among Bitis species, in that its venom is predominantly neurotoxicNeurotoxin
A neurotoxin is a toxin that acts specifically on nerve cells , usually by interacting with membrane proteins such as ion channels. Some sources are more general, and define the effect of neurotoxins as occurring at nerve tissue...
, so much so that effects of the bite seldom include necrosis or infection. The snake is described as "irascible", hissing violently and twisting convulsively if molested.
Presumably the neurotoxic venom is an adaptation to the prey, which largely comprise rock lizards and small amphibians. It does however also eat other animals such as small rodents and young of ground-nesting birds. The venom is not powerful enough for the dose injected at a single strike to kill an adult human, and there do not seem to be any records of human fatalities. However, whether at threat or not, patients do not seem to respond usefully to antivenin, so treatment should be limited to symptomatic control. Such as the effects of the venom are, they take effect quickly. Symptoms of the bite have been compared to alcohol intoxication and are not permanent. Unlike the bites of elapid snakes
Elapidae
Elapidae is a family of venomous snakes found in tropical and subtropical regions around the world, terrestrially in Asia, Australia, Africa, North America and South America and aquatically in the Pacific and Indian Oceans...
, Bitis atropos bites, though neurotoxic, do not cause obvious effects on heart and respiratory functions. However, they can be troublesome and their effects sometimes persist for some days or even weeks, which suggests that the venom causes nerve damage that does not mend quickly if it is severe. Obvious symptoms may include loss of smell or taste, drooping eyelids and loss of vision.