Puff adder

Identification

The puff adder is a heavy, thick-bodied viper with a flattened, broad head, upward-pointing nostrils, keeled scales and a very short tail^2,3. Its eyes have vertical pupils³. It may be almost black, brown, reddish or even orange above, with distinctive pale, black-edged U- or V-shaped marks along the back that become rings around the tail; the belly is pale with blackish marks².

Adults average about 0.8 m⁷. In southern Africa most are under 1 m from snout to vent, but some East African populations grow to more than 1.8 m³, and WHO gives a maximum total length of more than 190 cm². Its fangs are 16–18 mm long⁸.

Distribution

The puff adder is the most widespread and abundant viper in Africa³. It occurs across most of sub-Saharan Africa, from Senegal and Mauritania to Somalia and south to the Cape, and also in Morocco and Western Sahara, south-western Saudi Arabia and Oman¹. The Reptile Database notes that it is not found in Liberia, Algeria or Equatorial Guinea¹.

Two subspecies are recognised: the widespread B. a. arietans and B. a. somalica of Somalia and northern Kenya¹, which has keeled scales under its tail². WHO notes that the puff adder is probably a complex of more than one species².

Habitat

The puff adder lives in a wide variety of habitats, especially savanna and open grassland². It is absent only from true desert, rainforest and high mountain grassland^2,3. In the West African savanna it is one of the commonest causes of serious snakebite, and farm workers are among the people most often bitten².

Behaviour

The puff adder is an extreme ambush hunter³. It relies on camouflage and is reluctant to move; when hiding, it often does not hiss or strike as a person approaches, because this would give away its position⁵. Wild puff adders usually move less than 10 m a day and may wait in the same ambush spot for weeks³.

It is also hidden from smell: in tests, trained dogs and meerkats easily found other snakes by scent but could not pick out puff adders⁴. When threatened, it inflates its body and gives a loud hiss by blowing air out through its nostrils². Most people are bitten at night when they step on one by accident, although bites also happen by day when the snake is basking⁶.

Diet

The puff adder eats mammals, frogs and toads, birds and reptiles, with rodents and frogs the most important prey³. One study cited by the Reptile Database found that rodents made up 76% of its prey¹. It lures prey by wiggling its tongue or tail tip^3,5.

It needs little food: in a captive study, puff adders kept a steady weight on about 63% of their body weight in rodents a year, yet could eat up to 10 rodents at one sitting when food was plentiful³. A puff adder that has fattened up could probably go about two years without eating³.

Reproduction

The puff adder gives birth to live young^1,7. Mating has been reported from October to December, with the young born around April⁷. A litter usually holds 20–40 young, each about 23.5–25.5 cm long at birth⁷. Puff adders have been recorded hybridising with the Gaboon viper in the wild¹.

Venom and medical significance

The puff adder is thought to cause most serious snakebites in Africa as a whole, and it is the main cause of serious envenoming in eastern and southern Africa². It accounted for up to 75% of snakebites in one Zimbabwean study⁸. Its venom is strongly cytotoxic and also haemotoxic, causing severe pain, swelling that can spread up the whole limb to the trunk, blistering and tissue death that may lead to amputation^2,6. Fluid lost into the swollen limb can cause dangerous shock, and some patients have bleeding or blood-clotting problems^2,8.

Antivenoms that cover the puff adder include the South African (SAVP) polyvalent antivenom and EchiTAb-Plus-ICP². Anyone bitten should go to hospital immediately.

Conservation

The puff adder is listed as Least Concern on the IUCN Red List (assessed in 2021)⁹. It remains widespread and common³. As a major predator of rodents, it may help to control rodent outbreaks that damage crops³.

Similar species

Where forest and savanna meet, the puff adder can be confused with the Gaboon viper (Bitis gabonica) and the rhinoceros viper (B. rhinoceros)². These forest vipers have small horn-like scales on the nose, dark triangles below the eyes and a geometric pattern of pale rectangles and triangles, while the puff adder has simple pale, black-edged U- or V-shaped marks². The puff adder is also absent from rainforest, where the Gaboon vipers live². These differences are not a safe basis for handling any snake. Keep your distance from every snake you cannot identify.

In captivity

The puff adder is dangerously venomous and is not suitable as a pet. Captive puff adders have lived for almost 16 years⁷. In a 2025 review, more than half of the puff adder bites described in detail in the medical literature were from captive snakes⁸.