Eastern Garter Snake


Thamnophis sirtalis sirtalis
Thamnophis sirtalis sirtalis

Scientific name: Thamnophis sirtalis sirtalis (LINNAEUS 1758)
* Currently accepted name

* scientific names used through time

  • Coluber sirtalis LINNAEUS 1758
  • Tropidonotus concinnus HALLOWELL 1852
  • Eutainia sirtalis BAIRD & GIRARD 1853
  • Eutainia dorsalis BAIRD & GIRARD 1853
  • Eutainia infernalis — BAIRD & GIRARD 1853
  • Eutainia pickeringii — BAIRD & GIRARD 1853
  • Eutainia concinna — BAIRD & GIRARD 1853
  • Tropidonotus bi-punctatus – DUMÉRIL, BIBRON – DUMÉRIL 1854
  • Eutanaeia [sic] sirtalis – SHARP 1890
  • Eutaenia sirtalis – COPE 1893
  • Tropidonotus ordinatus var. sirtalis – DE GRIJS 1899
  • Thamnophis sirtalis sirtalis CONANT 1958
  • Thamnophis sirtalis – ROSSMAN 1965

Description: Average adult size is 20–28 inches (50.8-71.1 cm), record is 48.75 inches (123.8 cm). Adults are greenish with a light tan or gray mid-dorsal stripe. There is an additional light tannish stripe on each side of the body occupying the 2nd and 3rd dorsal scale rows above the belly. There are alternating rows of dark spots on each side between the mid-dorsal and lateral stripes. Light reddish-tan fleckings may also be present. The belly is uniform whitish-green. The scales of the upper lip are outlined with black markings. The scales are keeled, and there are 19 dorsal scale rows at midbody. The pupil is round. Juveniles are similar to adults.

Thamnophis sirtalis illustration

A. Top of the head
B. Underside of the head (chin and throat)
C. Front (face view) of the head
D. Keeled scales
E. Side of the head

Range: In Florida, the Eastern Garter Snake occurs throughout the state, excluding the Florida Keys and the Gulf coast from eastern Wakulla County in the panhandle south to Hernando County in the central peninsula. Outside of Florida, it is found throughout the eastern United States from southern Texas north into Canada and east to the Atlantic Ocean.

Habitat: Commonly found in pinelands, hardwood hammocks, cypress strands, prairies, marshes, and melaleuca stands.

Thamnophis sirtalis sirtalis
Thamnophis sirtalis sirtalis
Thamnophis sirtalis sirtalis
Thamnophis sirtalis sirtalis

Comments: HARMLESS (Non-Venomous). The Eastern Garter Snake is terrestrial and active during the day. It is frequently found along the banks of canals and ditches, and around houses in residential areas. After heavy rains, it is sometimes found at night crossing roads in search of food. It feeds on earthworms, small fishes, frogs, and salamanders. It is live-bearing. From 6-60 offspring are born from May-July. Newborns are 5-9 inches (12.7-22.8 cm) in length. It has lived up to 14 years in captivity.

Comparison with other species: The Bluestripe Garter Snake (Thamnophis sirtalis similis) has light blue stripes and tannish lateral fleckings, along with a uniform whitish-blue belly. The Eastern Ribbon Snake (Thamnophis sauritus) is thinner-bodied, has their light colored lateral stripes occupying the 3rd and 4th dorsal scale rows above the belly, and lacks black markings on the scales of the upper lip.

Thamnophis sirtalis sirtalis
Thamnophis sirtalis sirtalis