Photo credit:

Eric Centenero Alcala

Common name

Mexican Lance-Headed Rattlesnake

Scientific name

Crotalus polystictus

Conservation Status

Least Concern

Federal and State Protections

Sujeta a Protección Especial (Pr) - Mexico

Countries of Occurrence


States or Providence 

Zacatecas, Aguasalientes, Jalisco, Colima, Guanajuato, Michoacan, Queretaro, Hidalgo, Estado de Mexico (Mexico State), Tlaxcala, Puebla, Morelos, Mexico City (Mexico D.F.), Veracruz


Adult size

60cm (23.6in) - 100cm (39.4in)

Species Description

This small-to-medium-sized rattlesnake species can be found on the plateau of Central Mexico. at elevations of 4,500ft (1370m) to 8,500 ft. They occur in a variety of habitats from grasslands to pine-oak forests, rocky lava outcrops, grassy plains and even marshlands. This rather colorful rattlesnake species can be more tan, brown, gray, or white as a background to their distinctive "lancehead" spots. The Mexican lancehead rattlesnake's diet consists almost entirely of mammals. Males have a larger head than females and will eat larger prey as a result.

The scientific name of this species "polystictus" refers to its pattern: "poly" = many, "sticto" = spotted.

The venom composition and feeding behavior between adult and juvenile Mexican lancehead rattlesnakes is different and changes with maturity - a change known as an ontogenetic shift. Adults of this species will frequently bite-and-release their rodent prey, and their venom is less toxic on average and causes more hemorrhaging. Juvenile Mexican lancehead rattlesnakes will often bite-and-hold their prey, and their venom is slightly more toxic, consisting of more neurotoxic characteristics.

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