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western hog-nosed snake

western hog-nosed snake (Heterodon nasicus) [state threatened]
Photo by MDC Staff, courtesy Missouri Department of Conservation

Features and Behaviors


The western hog-nosed snake averages 15 to 25 inches in length. Its snout is upturned with a ridge on top. The belly is black. The scales are keeled (ridged). The body is gray-tan with brown blotches.


The western hog-nosed snake may be found in Illinois along the central Illinois River, the upper Mississippi River and in Kankakee County. It lives in sand prairies, savannas and nearby woodlots. The western hog-nosed snake is a slow-moving, terrestrial snake. It uses mammal burrows to remain underground in cold or wet weather. This snake will flatten its head and neck, hiss and inflate its body with air when disturbed, hence its nickname of “puff adder.” It may also vomit, flip over on its back, shudder a few times and play dead. The upturned snout is used to help dig prey items out of sandy soil. Mating occurs in the spring. The female lays from eight to 10 eggs in sand in July. Eggs hatch in August or September. The western hog-nosed snake eats amphibians, especially toads, lizards, mammals and ground-nesting birds. The saliva of this snake is toxic to prey. It is injected through the biting action of the large teeth in the back of the mouth.

Illinois Range


​Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Family: Dipsadidae

Illinois Status: state threatened, native

The threatened status is applied to this species because it is only found in sand prairies and adjacent areas. It is vulnerable to habitat destruction including changing the sand prairie land’s use to pine plantations or Christmas tree farms.