Mexican Garter Snake

The Mexican garter snake (Thamnophis eques) is a species of snake in the family Colubridae. It is found in Mexico and in the United States (Arizona and New Mexico). This harmless snake is semi-aquatic and most of the 10 recognized subspecies are restricted to lake basins in Mexico.

This snake ranges in habitat from deserts and sky island forests of Arizona and New Mexico to the thornscrub and rainforests of Mexico. One subspecies, the Lake Chapala garter snake (T. e. obscurus), is endemic to Lake Chapala.

This snake is a generalist carnivore, feeding on a wide variety of prey, such as lizards, frogs, toads, tadpoles, fish, and even from time to time earthworms, snails, insects, and small mammals.

In north-central Arizona, Northern Mexican garter snake potential aquatic prey captured during minnow trap surveys include nonnative species such as western mosquitofish, red shiners, green sunfish, bluegills, smallmouth bass, largemouth bass, yellow bullheads, black bullheads, common carp, and American bullfrogs (tadpoles, juveniles and subadults). As well as native species such as Woodhouse’s toads (tadpoles, juveniles and adults) and Sonora mud turtles (hatchlings).

Subspecies

Ten subspecies are known:

Mexican garter snake, T. e. eques (Reuss, 1834)

Laguna Totolcingo garter snake, T. e. carmenensis (Conant, 2003)

T. e. cuitzeoensis Conant, 2003

T. e. diluvialis Conant, 2003

T. e. insperatus Conant, 2003

Northern Mexican garter snake, T. e. megalops (Kennicott, 1860)

Lake Chapala garter snake, T. e. obscurus (Conant, 2003)

T. e. patzcuaroensis Conant, 2003

T. e. scotti Conant, 2003

T. e. virgatenuis Conant, 1963