NARROW-HEADED GARTER SNAKE } Thamnophis rufipunctatus
DESCRIPTION: The narrow-headed garter snake is unique among garter snakes in lacking stripes on its back and having a long, narrow head. This garter snake is olive to brown in color with dark, irregular spots, which are redder in young snakes. Its tongue is black, and its eyes occur high on the laterally compressed head. The tail is prehensile, which the snake can use to anchor itself while pursuing prey in swift current.
HABITAT: The narrow-headed garter snake is one of the most aquatic of all garter snakes and is typically found in well-lit, cool, clear, rocky streams with overhanging vegetation. It also uses upland areas adjacent to the water for retreat and hibernation sites and vegetation and rocks, both in and out of the water, as basking sites and cover for avoiding predators.
RANGE: This snake is found in Arizona and New Mexico.
MIGRATION: This snake does not migrate.
BREEDING: Mating occurs in warm microclimates along stream margins, with females emitting scent trails for males to follow. The narrow-headed garter snake is viviparous with births of six to18 young occurring in summer. Snout-to-vent length for young snakes at birth range from six to eight inches. Young snakes are on their own from birth.
LIFE CYCLE: Female narrow-headed garter snakes mature at two years and males at 2.5 years. No data are available on the life expectancy of these snakes.
FEEDING: The narrow-headed garter snake feeds primarily on fish but is also reported to eat tadpoles, frogs and salamanders. The species' elongated, narrow head is believed to be an adaption to reduce drag when the snake is striking prey in swift water and enhances its ability to hold position when facing into a current. The snake is a visually oriented predator and forages along streamside banks, particularly between boulders in the stream itself.
THREATS: Habitat destruction, nonnative predators and killing by humans threaten the species.
POPULATION TREND: This species is declining.