The puff adder, Bitis arietans, is a highly venomous viper species whose wide distribution across Africa and the Arabian Peninsula contributes to its notoriety. This snake is considered one of the most significant causes of snakebite fatalities throughout the African continent due to its potent venom and common presence in human-populated areas. The species’ scientific name, arietans, is derived from the Latin word meaning “striking violently,” a reference to its defensive behavior.
Physical Description and Identification
The puff adder is characterized by its robust and heavy body structure, giving it a stout, thick appearance. Most adults typically measure about one meter (3.3 feet) in total length, though larger specimens can reach up to 1.5 meters (4.9 feet) and weigh over six kilograms. The snake possesses a large, flattened, and distinctively triangular head, which is typical of many vipers and houses its long, hinged fangs.
Its coloration serves as effective camouflage, generally consisting of dull earth tones like straw yellow, light brown, or reddish-brown. This base color is overlaid with a striking pattern of dark brown or black backwardly directed bands, often forming chevron or U-shapes along its back. The rough texture of its body is due to heavily keeled scales, which help break up the snake’s outline and assist in blending into its environment.
Geographic Range and Preferred Habitat
The puff adder boasts one of the most extensive distributions of any African snake, covering nearly all of Sub-Saharan Africa and extending into parts of the Arabian Peninsula. Its habitat is remarkably diverse, including savannas, grasslands, open forests, rocky outcrops, and scrubland. The species is notably absent only from two environments: true deserts and dense, tropical rainforests.
Its preference for open areas and often dry, warm climates means it frequently inhabits regions where human settlements and agriculture are also common. This adaptability allows the puff adder to thrive across numerous ecosystems, from the far west of Africa to the Cape in the south.
Behavior and Hunting Strategy
The puff adder is an ambush predator that often remains motionless for extended periods, sometimes weeks, while waiting for prey to pass nearby. This sedentary behavior is coupled with a slow, caterpillar-like movement when it does move, contributing to the perception of it being sluggish. This stillness is a highly effective survival strategy, aided by its excellent visual camouflage and a unique form of chemical camouflage that hides its scent from predators.
When disturbed or threatened, the snake’s demeanor changes dramatically, adopting a tightly coiled defensive posture with its forebody held in an “S” shape. It will then inhale and exhale forcefully, producing a continuous, loud, sighing hiss or “puff” that gives the species its common name. Unlike many snakes that flee from approaching footsteps, the puff adder often relies on its camouflage until the last moment, only striking if it feels directly threatened. The strike itself is explosive, fast, and can be directed sideways as easily as forward, returning quickly to the defensive coil.
Medical Significance of the Bite
The puff adder’s venom is primarily cytotoxic, meaning it contains toxins that destroy local tissues and cells. A bite from this snake typically results in immediate, severe pain and extensive swelling at the wound site, which can spread rapidly to the entire limb. The tissue-destroying components cause blistering, bruising, and widespread superficial or deep necrosis, leading to permanent injury and potential loss of function without proper treatment.
The maximum venom yield from a single snake can be as high as 750 milligrams, though typical yields are between 150 and 350 milligrams. This large volume, combined with long fangs, contributes to the severity of envenomation. Systemic effects can also occur, including hypotension, blood clotting disorders, and shock, which are often the cause of death if left untreated. Prompt medical intervention involving the administration of specific antivenom is necessary to neutralize the effects of the venom and minimize the long-term disabilities.