#bitis arietans

A cape cobra (Naja nivea) eats a puff adder (Bitis arietans) in Nossob, South Africa

(Bitis arietans) puff adder 

A puff adder (Bitis arietans) flickers its tongue in Swakopmund, Namibia

(Bitis arietans) puff adder

This species is responsible for more snakebite fatalities than any other African snake. This is due to a combination of factors, including its wide distribution, common occurrence, large size, potent venom that is produced in large amounts, long fangs, their habit of basking by footpaths and sitting quietly when approached.

The venom has cytotoxic effects and is one of the most toxic of any vipers based on LD50. 

The LD50 values in mice vary: 

0.4–2.0 mg/kg IV, 

0.9–3.7 mg/kg IP, 

4.4–7.7 mg/kg SC.

 Mallow et al. (2003) give an LD50 range of 1.0–7.75 mg/kg SC.

Venom yield is typically between 150–350 mg, with a maximum of 750 mg. Brown (1973) mentions a venom yield of 180–750 mg. About 100 mg is thought to be enough to kill a healthy adult human male, with death occurring after 25 hours.

In humans, bites from this species can produce severe local and systemic symptoms. Based on the degree and type of local effect, bites can be divided into two symptomatic categories: those with little or no surface extravasation, and those with hemorrhages evident as ecchymosis, bleeding and swelling. In both cases there is severe pain and tenderness, but in the latter there is widespread superficial or deep necrosis and compartment syndrome. Serious bites cause limbs to become immovably flexed as a result of significant hemorrhage or coagulation in the affected muscles. Residual induration, however, is rare and usually these areas completely resolve.

Other bite symptoms that may occur in humans include edema, which may become extensive, shock, watery blood oozing from the puncture wounds, nausea and vomiting, subcutaneous bruising, blood blisters that may form rapidly, and a painful swelling of the regional lymph nodes. Swelling usually decreases after a few days, except for the area immediately around the bite site. Hypotension, together with weakness, dizziness and periods of semi- or unconsciousness is also reported.

If not treated carefully, necrosis will spread, causing skin, subcutaneous tissue and muscle to separate from healthy tissue and eventually slough with serous exudate. The slough may be superficial or deep, sometimes down to the bone. Gangrene and secondary infections commonly occurs and can result in loss of digits and limbs.

(Bitis arietans) Puff adder

Habitat: Most widely distributed venomous snake in Africa; encountered almost anywhere, at both low & high elevations, except for rain forests & extreme desert conditions. Found mainly in savannah or open grassland including areas w/ scattered scrubby bushes, from sea level to 3,500 m elevation. 

Activity and Behavior: Both diurnal & nocturnal, often basks in early morning or late afternoon; terrestrial but may climb sturdy bushes to bask. Usually sluggish; relies on camouflage to escape detection. Bad-tempered & excitable; when disturbed, makes long deep hissing noise. May move rapidly, coil into "S-shape" & strike suddenly & swiftly, but does not hold on. Eats small rodents, birds, amphibians & sometimes other snakes.