Bluestripe Garter Snake


Thamnophis sirtalis similis
Thamnophis sirtalis similis

Scientific name: Thamnophis sirtalis similis (ROSSMAN 1965)
* 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
  • Thamnophis sirtalis similis ROSSMAN 1965

Description: Average adult size is 20–26 inches (50.8-66 cm), record is 39.25 inches (99.6 cm). Adults are olive–brown to blue–black with a light blue mid–dorsal stripe. There is an additional light blue stripe on each side of the body occupying the 2nd and 3rd dorsal scale rows above the belly. Frequently there are light tannish fleckings on each side between the mid–dorsal and lateral stripes. The belly is uniform whitish–blue. 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 Bluestripe Garter Snake occurs along the Gulf coast from eastern Wakulla County in the panhandle south to Hernando County in the central peninsula. It is not found outside of Florida.

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

Thamnophis sirtalis similis
Thamnophis sirtalis similis
Thamnophis sirtalis similis

Comments: HARMLESS (Non-Venomous). The Bluestripe 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. See Eastern Garter Snake (Thamnophis sirtalis sirtalis).

Comparison with other species: The Eastern Garter Snake (Thamnophis sirtalis sirtalis) has yellowish-tan stripes and lateral reddish-tan fleckings, along with a uniform whitish-green belly. The Eastern Ribbon Snake (Thamnophis sauritus) is thinner-bodied, has 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.