These small vipers are found in arid regions in the Indian subcontinent, northern and western Africa, and the Middle East. They are responsible for more snakebites and deaths than any other serpent worldwide. When disturbed, they writhe to slide their sides past each other to produce a sizzling sound by the rubbing action of their rough scales. They will also readily strike at a disturbance, often so vigorously that they acually move their body forward toward the threat. Although small, their venom is extremely potent. On loose, sandy, or hot surfaces the saw-scaled vipers move by sidewinding.