Causus rhombeatus 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

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...

 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 subsaharan Africa. No subspecies are currently recognized.

Description

With an average length of 60 cm, this is the largest member of the genus Causus. The longest individual ever recorded was a 93 cm male collected in 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...

.

The head has a snout that is relatively blunt (i.e. more rounded that other members of this genus), on the sides of which the nostrils are positioned. The circumorbital ring consists of 2-3 preoculars, 1-2 postoculars, and 1-2 suboculars that separate the eye from the supralabials. The temporal scales

Temporal scales

In reptiles, the temporal scales are those scales on the side of the head between the parietal scales and the supralabial scales, and behind the postocular scales.There are two types of temporal scales:...

 usually number 2+3, sometimes 2+4, but very rarely 2+2 or 3+3. There are 6 supralabial scales, very rarely 7. The sublabial scales

Sublabial scales

In reptiles, the sublabial scales, also called lower-labials or infralabials, are those scales that border the mouth opening along the lower jaw. They do not include the median scale . The term labial originates from Labium , which refers to any lip-like structure...

 usually number 7 or 10, rarely 8 and very rarely 11, 12 or 13. The first 3-4 sublabials are in contact with the chin shields

Chin shields

Chin shields on a snake are scales found on the underside of the snake's head towards the anterior and touching the lower labial scales.Chin shields to the front of the snake are called anterior chin shields while those to the rear of the snake are called posterior chin shields....

. The posterior chin shields are small and often indistinguishable from the gulars.

At midbody there are 15-21 rows of dorsal scales

Dorsal scales

In snakes, the dorsal scales are the longitudinal series of plates that encircle the body, but do not include the ventral scales.When counting dorsal scales, numbers are often given for three points along the body, for example 19:21:17...

 that are moderately keeled and have a satiny texture. 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 120-166, the subcaudals 15-36.

The color pattern consists of a ground color that is usually some shade of brown (possibly pinkish or grayish-brown), but occasionally olive green. This is overlaid with a pattern of 20-30 rhombic

Rhombus

In Euclidean geometry, a rhombus or rhomb is a convex quadrilateral whose four sides all have the same length. The rhombus is often called a diamond, after the diamonds suit in playing cards, or a lozenge, though the latter sometimes refers specifically to a rhombus with a 45° angle.Every...

 blotches that have pale edges, as well as a sprinkling of black scales and oblique black bars on the sides. Each oblique black bar is topped by one or two black spots, each with a pale centre, and strongly resembling an eye. Northern populations may be patternless, making them difficult to identify, while in others the pale edges may be missing, the rhombic blotches may be a darker color, or there may even be a dark brown vertebral stripe. The head has a characteristic V-shaped mark that may be solid black, or brown with a black outline.

Common names

Rhombic night adder, demon night adder, Cape night adder, African night adder, Cape viper.

Geographic range

Savanna

Savanna

A savanna, or savannah, is a grassland ecosystem characterized by the trees being sufficiently small or widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach the ground to support an unbroken herbaceous layer consisting primarily of C4 grasses.Some...

s of subsaharan Africa from 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...

 east to 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...

, Ethiopia

Ethiopia

Ethiopia , officially known as the Federal Democratic Republic of Ethiopia, is a country located in the Horn of Africa. It is the second-most populous nation in Africa, with over 82 million inhabitants, and the tenth-largest by area, occupying 1,100,000 km2...

, Somalia

Somalia

Somalia , officially the Somali Republic and formerly known as the Somali Democratic Republic under Socialist rule, is a country located in the Horn of Africa. Since the outbreak of the Somali Civil War in 1991 there has been no central government control over most of the country's territory...

 and 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...

, south through 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...

, 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...

, Rwanda

Rwanda

Rwanda or , officially the Republic of Rwanda , is a country in central and eastern Africa with a population of approximately 11.4 million . Rwanda is located a few degrees south of the Equator, and is bordered by Uganda, Tanzania, Burundi and the Democratic Republic of the Congo...

, Burundi

Burundi

Burundi , officially the Republic of Burundi , is a landlocked country in the Great Lakes region of Eastern Africa bordered by Rwanda to the north, Tanzania to the east and south, and the Democratic Republic of the Congo to the west. Its capital is Bujumbura...

, 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...

, Angola

Angola

Angola, officially the Republic of Angola , is a country in south-central Africa bordered by Namibia on the south, the Democratic Republic of the Congo on the north, and Zambia on the east; its west coast is on the Atlantic Ocean with Luanda as its capital city...

, 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...

, 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...

, northern Botswana

Botswana

Botswana, officially the Republic of Botswana , is a landlocked country located in Southern Africa. The citizens are referred to as "Batswana" . Formerly the British protectorate of Bechuanaland, Botswana adopted its new name after becoming independent within the Commonwealth on 30 September 1966...

, 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...

, 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...

, and eastern 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...

 to Riverdale in the Western Cape Province. No type locality is listed.

Behavior

This is an active species that can often move relatively quickly—up to an estimated speed of 92 cm per second. They are usually found on the ground, but have no trouble climbing or swimming. They are largely nocturnal, but are often seen basking in the early morning or late afternoon. However, Harper (1963) reported collecting a dozen specimens that were all active during the heat of the day.

Most specimens are docile, seldom attempting to bite unless severely provoked. FitzSimons is quoted in Pitman (1938) as saying that that, in captivity, they "become so tame that you may allow them to creep, climb and slither round your neck and inside your garments." Others, however, are more temperamental.

When seriously disturbed, they will put on a "ferocious" threat display that includes coiling up, inflating the body (making the dark markings stand out), hissing and puffing loudly, flattening the anterior portion of the body, and striking frantically. They may also flatten the neck and move forward with the tongue extended, much like a small cobra. Striking is done with such vigor that small specimens may lift themselves off the ground entirely.

Reproduction

Females produce an average clutch of two dozen eggs that require a lengthy incubation period of approximately four months. The hatchlings are 10-12.5 cm in length and feed on tiny frogs and toads.

Venom

The few documented bites involved pain and minor swelling with minimal necrosis. These symptoms usually disappear within 2-3 days. There have been no modern well-documented cases to back up earlier claims of fatalities due to bites from this species. Venom yield has varied from 20-30 mg to 300 mg, but the venom toxicity is low with values of 10.8, 14.6, >16.0 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...

 and 15 mg/kg SC being reported.

External links

• Causus rhombeatus image at FotoTime. Accessed 6 June 2007.
• Causus rhombeatus image at Cape Reptile Institute. Accessed 6 June 2007.
• Causus rhombeatus image at CalPhotos. Accessed 6 June 2007.. Accessed 13 December 2007.