How to Identify the Mexican Hognose Snake (Identification Guide)

Key identifying features

The Mexican hognose snake (Heterodon kennerlyi) is identified by its distinctly upturned, shovel-like snout, stout body, and bold dark blotches on a tan to gray background. The pronounced upturned nose scale, more sharply hooked than in most other hognose species, is the clearest diagnostic trait.

Coloration & pattern

The background color ranges from tan, gray, to yellowish-brown, marked with a row of large dark brown to black blotches down the back, often alternating with smaller blotches along the sides. The pattern can be quite variable in intensity, and some individuals show a more muted, washed-out appearance, but the blotched design remains discernible in nearly all specimens.

Head, eyes & scales

The most notable feature is the strongly upturned, keeled rostral scale at the tip of the snout, more pronounced and sharply hooked than in the closely related eastern and plains hognose snakes. The head is broad and somewhat triangular in outline due to this upturned nose and flared jaw muscles, though the snake is non-venomous to humans. Eyes are moderate with round pupils. Body scales are keeled, giving a rough texture.

Size & body shape

Adults typically reach 40 to 70 cm (16 to 28 inches), with a stout, heavy-bodied build and a short tail. The body appears thick relative to its length compared to many other colubrids.

Range & habitat where you'll see it

This species occurs in the desert Southwest, including southern New Mexico, southeastern Arizona, and western Texas, extending into northern Mexico, favoring arid grasslands, desert scrub, and sandy or gravelly soils where it burrows and hunts toads. When threatened, it performs a dramatic defensive display, flattening its neck like a hood, hissing loudly, and feigning death, behaviors shared with other hognose species.

How to tell it apart from look-alikes

The plains hognose snake (Heterodon nasicus) is very similar and was until recently considered the same species; the Mexican hognose has a somewhat more sharply upturned snout and occupies a more southerly, arid range overlapping in parts of Texas and New Mexico. The eastern hognose snake has a less sharply upturned snout and inhabits more easterly, sandy woodland habitats. Gopher snakes can show similar blotching but have a normal, non-upturned snout and lack the dramatic hooding threat display. The sharply upturned snout combined with desert range is the best way to identify this species.