Which type of snake is shown in the Mexican flag’s coat of arms?

A rattlesnake is the type of snake shown in the Mexican flag’s coat of arms.

The emblem depicts a golden eagle perched on a prickly pear cactus while gripping a rattlesnake in its beak and talon. This scene refers to the Mexica foundation story: their people were instructed to build their city where they saw an eagle on a cactus.

The flag does not identify the snake as one particular species. Mexico has several native rattlesnake species, including the western diamondback and the Mexican west coast rattlesnake, so “rattlesnake” is the precise conventional answer rather than a species name.

The emblem’s imagery has changed in artistic detail over time, but the eagle, cactus, and snake have remained its defining elements. Mexico City was founded at the site traditionally associated with the vision, on an island in Lake Texcoco.