This is unlike the Gaboon viper, the largest of the vipers, which uses a considerably larger amount of venom. Small doses of the snake's primarily hemotoxic venom can be deadly. When approached, they often reveal their presence by hissing that sounds almost like a shriek it is said to be the loudest hiss of any African snake.
Butterfly vipers are generally placid creatures. Holding them by the tail is not safe as it is somewhat prehensile, they can use it to fling themselves upwards and strike. They are slow-moving but capable of striking quickly, forwards, or sideways, without coiling first or giving a warning. Butterfly vipers prefer to hunt by ambush, and probably spend much of their life motionless, waiting for prey to wander by. They are sometimes found in shallow pools and have been described as powerful swimmers. This climbing behavior is aided by a partially prehensile tail.
Although mainly terrestrial, they are also known to climb into trees and thickets, where they have been found up to 3 m (9.8 ft) above the ground. Their vivid coloration actually gives them excellent camouflage in the dappled light conditions of the forest floor, making them almost invisible. They hide during the day in leaf litter, in holes, around fallen trees or tangled roots of forest trees. Butterfly vipers are solitary and primarily nocturnal creatures.