Common death adder

Identification

The common death adder has a broad, triangular head, a narrow neck, a short, thick body and a thin tail that ends in a soft, curved tip^1,2. Its colour ranges from grey to rich reddish-brown, usually with irregular dark crossbands and dark bars on the lips². The belly is whitish with black or brown flecks, the tail tip is cream or black, and the small eyes have a vertical pupil². Snakes from south-eastern Australia are especially wide-bodied, with relatively larger heads than other death adders⁴. Adult males average about 44 cm and females about 58 cm, and the largest reach about 1 m^1,2.

Distribution

The common death adder occurs from central Queensland through New South Wales to the southern parts of South Australia and Western Australia². The Reptile Database lists it from Queensland, New South Wales, Victoria, South Australia and Western Australia, and also from Papua New Guinea³. It notes that the genus urgently needs revision and that several undescribed species probably exist, especially in New Guinea³. Two New Guinea forms once treated as subspecies of this snake, Acanthophis laevis and A. rugosus, are now recognised as separate species³.

Habitat

This snake lives in a wide variety of well-drained habitats, including rainforest and wet sclerophyll forest, woodland, shrubland, grassland and coastal heath^1,2. It prefers sites with deep, settled leaf litter². It spends much of its time lying concealed under loose sand, leaf litter or low plants².

Behaviour

The common death adder is a sedentary, ground-dwelling snake². It may be active by day, but it is most often found at night, when it moves between shelter sites². Unlike most Australian venomous snakes, it does not search for food but waits in ambush with its body coiled and its tail tip near its head^1,2. It lures prey by wriggling the tip of its tail like a worm or caterpillar while it lies hidden and coiled, then strikes quickly^1,2. If threatened, it flattens its whole body into a rigid, curved coil and makes short, rapid strikes².

Diet

The common death adder eats frogs, lizards, birds and small mammals^1,2. Its diet changes with age: young snakes eat mainly lizards and frogs, while adults take more mammals and birds². A study of more than 750 museum specimens found that death adders as a group eat mostly lizards, and that mammals are common prey of the common death adder in south-eastern Australia⁴. After striking, it injects its venom and waits for the prey to die before eating it¹.

Reproduction

The common death adder gives birth to live young^1,4. Mating usually takes place in spring, but females breed only every second year, and the young are typically born in February or March². Litters contain between 2 and 42 young². Males mature at about 24 months and females at about 42 months². Female death adders grow about 20% longer than males, and male combat has never been reported in the genus⁴.

Venom and medical significance

The common death adder has relatively large fangs and toxic venom, and before antivenom was introduced about 60% of bites to people were fatal¹. The World Health Organization lists it in Category 2 in Australia, which covers highly venomous snakes that are less often involved in bites or less well studied⁷. In an Australian study of 29 death adder bites involving several species, 12 of the 14 envenomed patients developed paralysis, such as drooping eyelids, double vision and difficulty swallowing, and two needed a machine to help them breathe⁵. Death adder bites do not cause the clotting problems seen with many other Australian snakes^5,6. Death adder antivenom binds the venom in the blood, but in that study it did not reverse paralysis that had already started, and the weakness took a median of 21 hours to resolve⁵. Anyone bitten should go to hospital immediately.

Conservation

The common death adder is listed as Least Concern on the IUCN Red List, based on an assessment published in 2018⁸. In Queensland it is listed as Vulnerable under the state’s Nature Conservation Act 1992². Known threats include being killed on roads and being poisoned after trying to eat introduced cane toads². Suspected threats include land clearing, unsuitable fire regimes, trampling by livestock, predation by feral cats, foxes and pigs, and deliberate killing².

Similar species

With its viper-like shape, a death adder is easy to tell apart from most other Australian snakes⁵. Several other death adder species live in Australia, but the common death adder is the only one in the Sydney region¹. Desert death adders, such as Acanthophis pyrrhus and A. wellsi, are much more slender than the heavy-bodied southern common death adder⁴. These differences are not a safe basis for handling any snake. Keep your distance from every snake you cannot identify.

In captivity

The common death adder is dangerously venomous and is not suitable as a pet. In an Australian study of death adder bites, 15 of the 29 patients were snake handlers, and two handlers who had been bitten before had allergic reactions to the venom⁵. In New South Wales, keeping venomous native reptiles requires an advanced reptile keeper licence and references confirming experience in handling them⁹.