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Canadian Herpetological Society

Société d'herpétologie du Canada

Heterodon nasicus
Western Hog-nosed Snake / Couleuvre à Nez Retroussé

Western Hog-nosed Snake

The Hog-nosed Snakes, and other roboust, rear-fanged snakes, which were included within the Family Colubridae, have recently been placed in the Family Xenodontiidae.

The Western Hog-nosed has a tan, gray or yellowish gray body with large dark blotches down the back and several rows of smaller spots down the sides. It has a sharply upturned and pointed snout. The Western Hog-nosed Snakes is thick bodied with a broad neck. The scales are keeled. Maximum length is just under a metre.

Confusing Species
Other prairie species with bold blotches are the Bullsnake and the Prairie Rattlesnake. Neither of these species has an upturned snout. The Prairie Rattlesnake has a rattle at the tip of the tail and a distinctly triangular head. Bullsnakes have a decidely checkered pattern to their blotches. The Eastern Hog-nosed Snake is very similar although in Canada it is only found in Ontario. The underside of the belly is more mottled than blotched and the snout is not as sharply upturned.

Within Canada, the Western Hog-nosed Snake is found in southern Manitoba, Saskatchewan and Alberta. It is distributed in the central plains south into Mexico.

This species is found in sandy or gravelly areas within the prairies or adjacent scrubland or floodplains.

Mating and courtship behaviour have not been observed in the wild. Females lay 4-23 eggs each summer. Hatchlings are about 17 cm total length.

Natural History
The Western Hog-nosed eats toads, frogs, salamanders, lizards and other snakes as well as small rodents and some invertebrates. It has specialized teeth at the back of the mouth which are used to puncture toads that have inflated themselves. The upturned snout is used for digging in loose soil. When threatened an individual may either spread its neck like a hood, hiss and strike or else play dead. It may bite if handled and although it has a mild venom it is not toxic to humans. It can live for up to eight years.

Conservation Concerns
The Western Hog-nosed Snake may be declining on the prairies but no detailed information is available.