Western Hognose Snake

Overview

The Western Hognose Snake (Heterodon nasicus), often affectionately referred to by herpetologists as the ‘plains hognose,’ is a charming, stout-bodied colubrid snake native to the sweeping grasslands and prairie sandhills of central North America. World-famous for its sharply upturned, shovel-like rostral scale that gives its snout a comical pig-like appearance, the western hognose is an extraordinary burrowing specialist. Renowned on social media and across wildlife biology for its melodramatic defensive theatrics—including flattening its neck like a cobra and staging elaborate, death-feigning performances (thanatosis)—it is one of the most culturally beloved snakes in North America.

Ecologically, Heterodon nasicus operates as a specialized toad-hunting predator in prairie ecosystems. Inhabiting loose, sandy soils, hognose snakes utilize their modified rostral shovels to unearth buried toads and spadefoots. Armed with enlarged, rear-grooved maxillary teeth and specialized physiological resistance to lethal bufotoxin skin secretions, the hognose thrives on toxic amphibians that would kill other predators. In turn, hognose snakes provide essential prey for red-tailed hawks, coyotes, and kingsnakes.

Biology and Physical Characteristics

The morphology of the Western Hognose Snake is a fascinating evolutionary compromise between fossorial burrowing and aggressive mimicry. Its body is short, heavy-set, and keeled, colored in shades of light tan, olive-gray, or pale brown with 35 to 50 dark brown or black blotches running down the spine, creating a superficial resemblance to venomous prairie rattlesnakes. The snout features an exaggerated, sharply upturned and sharply keeled rostral scale that functions as a miniature subterranean bulldozer, slicing through sandy soils to unearth concealed toads. The snake is mildly rear-fanged (opisthoglyphous): at the back of its upper jaws sit two enlarged, ungrooved teeth used to puncture inflated toads, delivering an amphibian-specific saliva-like venom produced by Duvernoy’s glands that is harmless to humans but quickly immobilizes toads. Their liver is disproportionately large, packed with specialized enzymes that neutralize deadly toad toxins.

Behavior and Ecology

When confronted by a potential predator, the western hognose puts on an Academy Award-winning defensive performance in two distinct acts. In Act One, the snake attempts intimidation: it flattens its head and neck into a broad cobra-like hood, inflates its body with air, and emits loud, explosive hisses while making false strikes with its mouth closed. If this bluff fails to deter the attacker, the snake immediately launches Act Two: thanatosis (playing dead). The snake convulses violently, rolls onto its back, lets its tongue loll out into the dirt, emits foul-smelling musk and drops of blood from its cloaca, and lies completely limp. If flipped right-side up by a human hand, the snake will instinctively roll right back onto its back, firmly insisting that it is deceased! Mating occurs in early spring, with females depositing 4 to 25 white leathery eggs in moist sand burrows in early summer.

Conservation and Human Impact

Heterodon nasicus is evaluated as Least Concern by the IUCN Red List, supported by a large, contiguous distribution across the Great Plains. However, peripheral populations at the northern and eastern edges of its range—such as in Alberta, Manitoba, and parts of Illinois and Iowa—are protected as species of special concern due to extensive loss of native prairie grasslands to intensive corn and soybean agriculture. The species is exceptionally popular in the international reptile hobby, with hundreds of captive-bred color morphs (such as anaconda, axanthic, and albino) bred worldwide, eliminating pressure on wild populations.

Interesting Factoid

If you flip a ‘dead’ western hognose snake right-side up while it is playing dead, it will instantly roll right back onto its back with its tongue hanging out, stubbornly insisting that a proper dead snake only lies belly-up.