Mexican Garter Snake - Illustration by George Maleski

Mexican Garter Snake
Thamnophis eques megalops


The Mexican garter snake is a stout-bodied snake ranging from eighteen to forty inches in length. It is brown or greenish-brown with a yellowish back stripe and another stripe running parallel to each side. Large brown patches on the head are separated from the mouth by a greenish crescent.

Habitat: The Mexican garter snake is found in desert-grassland cienegas, in or along streams in valley floors, and occasionally in desert and lower oak woodland habitats.

Range: The snake ranges from central and southeastern Arizona to Oaxaca, Mexico. The range in Arizona is from the southeast corner of the San Rafael and Sonoita grasslands to Arivaca. It can also be found along the Agua Fria, Oak Creek, and Verde Rivers, and along some parts of the Salt and Black Rivers.1

Reproduction: The Mexican garter snake is live-bearing, with up to twenty-five young born. Births usually take place from June to July.

Diet: The snake eats fish, frogs, and small mammals. The snake is a predator of leopard frogs.

Status: The Mexican garter snake is considered a Species of Concern by the U.S. Fish and Wildlife Service, and is also a Wildlife Species of Concern in Arizona.

The Mexican Garter Snake in Pima County: The Mexican garter snake has been found in the Baboquivari and Cienega Creek areas in Pima County. The snake is preyed upon by bullfrogs, an exotic species which is causing the decline of many native species. Other threats to the snake include habitat degradation and destruction. Historically, the snake occurred in the Santa Cruz and Rillito rivers.2


1. Arizona Game and Fish Department. 1998. Thamnophis eques megalops. Heritage Data Management System.

2. Recon. 2001. Priority Vulnerable Species. Pima County Administrator's Office, Tucson, AZ.

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