Common Garter Snake (Thamnophis sirtalis) in the wild — Catch'Um species field guide

Common Garter Snake (Thamnophis sirtalis) wildlife photograph

Overview

Common garter snakes are slender, striped snakes found across much of North America. They hunt frogs, worms, and fish near water and gardens, and are among the first reptiles to emerge on warm spring days.

For US collectors, the garter snake is a common yard reptile — lengthwise stripes, harmless to people, and an easy wetland-edge find.

Scientific nameThamnophis sirtalis
Length45–120 cm
Weight100–300 g
LifespanAround 4–10 years in the wild
DietEarthworms
ConservationLeast Concern
RegionUS Gardens & Wet Edges

Habitat

Garden edge
Marsh margin
Meadow
Forest stream

Meadows, gardens, marshes, and forest edges near water across most of the United States and Canada, sheltering under rocks, boards, and dense vegetation.

Countries found

Common Garter Snake in United States

Field notes

Field scale for the Common Garter Snake: length around 45-120 cm; weight 100-300 g. Typical lifespan: Around 4-10 years in the wild.

When you are scanning habitat, prioritise garden edge, marsh margin, meadow, and forest stream. Those settings are where a clean look and a usable photo are most likely.

Quick ID anchor: Slender snake with usually three pale longitudinal stripes and a checkered or spotted pattern between. Confirm with behaviour and habitat before you log the discovery.

Diet

Earthworms, frogs, tadpoles, fish, salamanders, and small rodents.

Active hunters that chase prey through grass and shallow water.

Behaviour

Diurnal to crepuscular; bask then hunt along damp edges.

May release foul musk and strike defensively if grabbed.

How to identify

Slender snake with usually three pale longitudinal stripes and a checkered or spotted pattern between.

Head slightly wider than the neck; colour varies widely by subspecies.

Interesting facts

01
Usually show three light stripes on a darker body.
02
Non-venomous to humans though they may musk when handled.
03
Live-bearing — give birth to litters of live young.
04
Eat frogs, worms, fish, and other small prey.
05
Among the most cold-tolerant North American snakes.
06
Often share communal winter dens in the north.

Conservation status

LC: Least Concern

Common garter snakes are Least Concern and remain widespread. Local declines follow wetland drainage, road mortality, and persecution despite their harmless nature.

Sources: IUCN Red List