Snake FinderField Guide · Worldwide

Tell them apart

Mexican Bull Snake vs. Totonacan Rattlesnake

It matters: the Totonacan Rattlesnake is venomous, while the Mexican Bull Snake is harmless.

Mexican Bull Snake

Mexican Bull Snake

Pituophis deppei

Harmless
Family
Colubridae
Group
Gophersnake / Bullsnake
Size
Large, 4–7 ft.
Identify
Large, blotched, with a slightly pointed snout and keeled scales — no rattle.
Totonacan Rattlesnake

Totonacan Rattlesnake

Crotalus totonacus

Venomous
Family
Viperidae
Group
Rattlesnake
Size
Typically 2–5 ft; some species exceed 6 ft.
Identify
Heavy body, broad triangular head, vertical (cat-like) pupils, and a segmented keratin rattle at the tail tip.

How to tell them apart

Gophersnakes and bullsnakes mimic rattlesnakes by hissing and vibrating the tail, but they are harmless and have no rattle.

Never rely on a single feature to judge a live snake. If you cannot positively identify it, keep your distance. Informational only.