What venomous snake species is commonly called the puff adder?

The venomous snake species commonly called the puff adder is Bitis arietans.

Bitis arietans is also called the African puff adder or common puff adder. It is a large viper found across much of sub-Saharan Africa and in parts of the Arabian Peninsula. The species favors savannas, grasslands, and rocky country, although it avoids true deserts and dense rainforests.

Its name refers to a famous defensive behavior. When disturbed, the snake may inflate and deflate its body while hissing loudly, creating a conspicuous puffing display. It usually relies on camouflage and ambush rather than actively chasing prey. Its diet includes rodents, birds, amphibians, lizards, other snakes, and occasionally small mammals.

Bitis arietans is a viper, not an elapid such as a cobra or mamba. The genus Bitis contains several African vipers, and some are also called adders or puff adders in common usage. The species was formally described by German naturalist Blasius Merrem in 1820; arietans refers to striking violently.