Western Hognose Snake

Heterodon nasicus nasicus

Species at Risk: May Be At Risk


Western hog-nosed snakes are described as being a small, heavy-bodied snake. The “hog-nose” in their common name refers to the upturned, spade-like snout, which they use to burrow and dig out their primary food source, toads. They are naturally resistant to the toxins produced by toads as defense against predators. They do also eat frogs, salamanders, lizards, snakes (particularly garter snakes), birds, small mammals, bird and reptile eggs.

Western hog-nosed snakes are diurnal, meaning that they are active during the day.

Adult Hog-nosed snakes can reach 75 cm in length, with the females typically being larger than the males. They are oviparous (laying eggs, not giving birth to live young), and can lay 4-23 eggs. In Alberta, eggs are deposited from mid-June to early July. The incubation period is about 60 days.

Hog-nosed snakes are famous for their threat displays. They will hiss and flatten themselves to make themselves look larger, and will even exhibit closed-mouth strikes. If the bluff fails to deter the threat, they will fake death, flipping on their backs, gaping the mouth, hanging the tongue out, and salivate. Of course, snakes performing this behavior are deeply stressed, so please do not try to provoke this behavior if you meet one.

Interestingly, these snakes until fairly recently were considered non-venomous. Though they still did not present a risk to humans (there has never been a reported death due to a Hog-nose bite), recent evidence shows that they are actually rear-fanged, with large, ungrooved teeth, and mildly venomous. They produce the venom (or toxin, depending on who you believe), in Duvernoy’s Gland, which is a modified salivary gland, not a venom gland as found in other better known venomous snakes. Their fangs are also not hollow, so they cannot inject the venom, and must depend on a chewing action to get the venom into the wounds cause by their teeth.

Western hog-nosed snakes (Heterodon nasicus nasicus) can be found in the short and mixed grass prairie of the south-eastern corner of Alberta. Southern Alberta appears to be the most northern limit of their range. In Alberta, they have most frequently been reported in sandy locations within the grasslands, but this may be the result of sampling bias (we expected to find them there, therefore we search there more frequently). Throughout their range (outside Alberta), they are known to inhabit sandy and gravelly prairies, open brushland, woodlands, farmland, and floodplains.

We have insufficient information on the Western Hog-nosed snakes in Alberta to know what their true status is. Certainly, they are considered to be rare in Alberta, but current evidence suggests that their populations are stable. Possible limiting factors and threats for Hog-nosed populations in Alberta may include lack of suitable habitat, agricultural activities, and road mortalities.

Peterson Field Guides: Western Reptiles and Amphibians (3rd ed) by Robert C Stebbins.
External link opens in new tab or window Alberta Conservation Association
External link opens in new tab or window U Alberta Biology
External link opens in new tab or window Wikipedia Western Hognose Snake
External link opens in new tab or window Wildlife Status Report

Photo by LA Dawson / Austin Rescue Services