Any of three or four species (genus Heterodon , family Colubridae) of harmless North American snakes named for their upturned snout, which is used for digging.
When threatened, they flatten the head and neck, then strike with a loud hiss, but rarely bite. If their bluff fails, they roll over, writhing, and then act dead, with mouth open and tongue lolling. They eat chiefly toads and frogs. Heavy-bodied and blotchy, they are usually about 24 in. (60 cm) long. Though not adders , they are sometimes called puff adders or blow snakes.