any harmless North American snake of the genus Heterodon, the several species having an upturned snout and noted for flattening the head or playing dead when disturbed.
hog·nose snake (hôg'nōz', hŏg'-) n. Any of several thick-bodied, nonvenomous North American snakes of the genus Heterodon having an upturned snout. Also called puff adder.