Common Garter Snake
Thamnophis sirtalis

Family Colubridae

Adults to 49" in length. Color black, gray, or brown; prominent yellow stripe on back, pale stripe on sides; red blotches between dorsal and lateral stripes. Moderately slender body; keeled scales. Single anal plate.
Elevation Range:
Below 6000' in northeastern Colorado.
Subspecies in Colorado:
Thamnophis sirtalis parietalis
  Common Garter Snake
Photo from Hammerson, 1986.
Used with permission.
CountyRef. CountyRef. CountyRef. CountyRef.
AdamsH Dolores  La Plata  Pitkin 
Alamosa  Douglas *  Lake  Prowers 
Arapahoe *  Eagle  LarimerH Pueblo 
Archuleta  El Paso  Las Animas  Rio Blanco 
Baca  Elbert  Lincoln  Rio Grande 
Bent  Fremont  LoganH Routt 
BoulderH Garfield  Mesa  Saguache 
Chaffee  Gilpin  Mineral  San Juan 
Cheyenne  Grand  Moffat  San Miguel 
Clear Creek  Gunnison  Montezuma  SedgwickH
Conejos  Hinsdale  Montrose  Summit 
Costilla  Huerfano  MorganH Teller 
Crowley  Jackson  Otero  WashingtonH
Custer  JeffersonH Ouray  WeldH
Delta  Kiowa  Park  YumaGAH13
Denver *  Kit Carson  Phillips * 
Map of Colorado
Color Key
Adams Alamosa Arahapoe Archuleta Baca Bent Boulder Chaffee Cheyenne Clear Creek Conejos Costilla Crowley Custer Delta Denver Dolores Douglas Eagle El Paso Elbert Fremont Garfield Gilpin Grand Gunnison Hinsdale Huerfano Jackson Jefferson Kiowa Kit Carson La Plata Lake Larimer Las Animas Lincoln Logan Mesa Mineral Moffat Montezuma Montrose Morgan Otero Ouray Park Phillips Pitkin Prowers Pueblo Rio Blanco Rio Grande Routt Saguache San Juan San Miguel Sedgewick Summit Teller Washington Weld Yuma