PUFF ADDER VERY DANGEROUS

Adders are abundant and occur in, or close to, most major cities in southern Africa. They account for many of the snakebites serious enough to require medical attention – the majority, in many regions, the work of the Puff Adder.

Most adders are short and stubby, with large erectile fangs in the front of the mouth. When not in use, the fangs are folded back within their sheaths against the roof of the mouth. They have keeled scales, those on the head and on the body similar in size. Night adders (Causus spp.) are generally less stubby and their heads are not as triangular as those of other adders. They have smooth scales, their head scales larger than their body scales. Night adders have shorter fangs than other adders and the longest venom glands (relative to body size) of all snakes.

Adder venoms are predominantly cytotoxic or cell-destroying, i.e. they are responsible for the destruction of blood vessels and tissue. Symptoms are localized and bites are often extremely painful, followed by severe swelling as a result of internal bleeding and, in some cases, blistering and death of tissue. This, coupled with secondary infection, may even make amputation necessary. Bites from small adder species, although painful and unpleasant, are usually not as serious.

Length: Adults average 90 cm in South Africa, but may reach 1,4 m. In Kenya specimens of over 1,8 m have been recorded, making this Africa’s largest adder. Scale count: The dorsal scales are keeled with 29–41 rows at midbody, 123–147 ventral scales and 14– 38 paired subcaudals. The anal shield is entire. There are 12–17 upper labials, no preoculars and 12–16 scales around the eye. There are 13–19 lower labials.

Colour: Above, variable from bright yellow to light yellow, yellow-brown, orange-brown, light brown or grey, with distinct, more or less regular chevron-like dark markings over the back, and dark bands or bars on the tail. A dark blotch on the crown of the head is separated from another blotch above the snout by a light line between the eyes. On the side of the head are 2 dark oblique bands, 1 below and 1 behind the eye. Below, yellowish white to grey with black blotches. Generally, specimens from the drier west (e.g. North West Province) are paler, and those from the wetter east are darker. Specimens are dull just before, and vividly marked after, sloughing of the skin.

Preferred habitat: Puff Adders are common throughout most of southern Africa, except for mountain- tops, true desert and dense forests. This snake does not occur naturally in and around the greater Johannesburg region.

Habits: A slow-moving, bad-tempered and excitable snake that may hiss or puff when disturbed. The Puff Adder is a stout snake with a thin neck and triangular head. The eyes are small with a vertical pupil, the snout rounded and the nostrils large, pointing upwards. Usually found on the ground but it may venture onto small shrubs or bushes to sun itself. It hides in thick grass or under bushes, down holes and under any form of ground cover. Mainly active at night but known to bask in the day, especially in the rainy season. It often basks on tarred roads where it may be killed by passing vehicles. It relies on its excellent camouflage to escape detection and prefers to freeze, rather than move off. People frequently step onto or close to Puff Adders and then get bitten. Although it is a sluggish snake it strikes rapidly, often drawing the head back with the body in an S-shape before lunging forward to strike. This snake usually moves forward in a straight line in what has been described as a ‘caterpillar-like’ motion but, when disturbed, it may move rapidly in the normal serpentine motion. Like most other snakes, it swims well.

Similar species: May be confused with the Gaboon Adder (Bitis gabonica) or some of the smaller adders. Note that none of the harmless snakes within our range resembles the Puff Adder.

Enemies: Man, warthogs, birds of prey and other snakes.

Food and feeding: Usually waits in ambush in a spot where it can remain motionless for hours. It feeds on rats and mice, other small terrestrial mammals including hares, ground birds, lizards, toads and, occasionally, other snakes. Large prey are usually bitten and then released and left to die. The Puff Adder then follows its prey’s scent with a flickering tongue. The prey is swallowed headfirst. A member of this species is known to have eaten a juvenile tortoise.

Reproduction: Viviparous, giving birth in late summer to 20–40 young, though exceptional broods of 80 have been recorded. The young, measuring 15–20 cm, are born in a fine membranous sac from which they break free soon after birth. A female from Kenya, housed in a Czech zoo, gave birth to 156 young, the largest number of young produced by any snake species in the world. Males are known to engage in wrestling during the mating season. Females produce a pheromone that attracts males. Several males may follow the scent of a single female.

Danger to man: Because it relies on camouflage to escape detection, this bad-tempered snake with its long fangs (up to 18 mm) and potent venom features prominently in snake-bite accidents and is often considered Africa’s most dangerous snake. It accounts for most serious snakebites in southern Africa.

Venom: A potent cytotoxic (cell-destroying) venom that attacks tissue and blood cells. Other than immediate shock, symptoms include extreme pain, excessive swelling and sometimes blistering at the site of the bite. Most victims are bitten on the lower leg. The venom is slow acting, usually taking 24 hours to cause death if not treated or if treatment is unsuccessful. It is uncommon for victims to die in a shorter period, although fatalities within 30 minutes have been recorded. With fatal bites, the victims usually succumb to complications associated with extensive swelling or kidney failure. Less than 10% of Puff Adder bites result in death. Tissue damage may result in the loss of digits or limbs. Antivenom will be required in serious cases.

Subspecies: Only the typical Puff Adder race (Bitis arietans arietans) occurs within our range.

Information courtesy of A Complete Guide to the Snakes of Southern Africa, written by Johan Marais and published by Random House Struik. For more information visit www.reptileventures.com