# Common Garter Snake (*Thamnophis sirtalis*)

> The common garter snake (Thamnophis sirtalis) is North America's most familiar harmless snake, striped and often found in gardens, wetlands, and woodland edges from Canada across most of the United States. Adults average about 0.7 m, eat amphibians, fish, and worms, and are listed Least Concern — including famous Manitoba mating balls.

- **Category:** Reptile
- **Conservation status (IUCN):** Least Concern
- **Range:** Most of the United States and southern Canada, excluding deserts of the Southwest.
- **Canonical page:** https://globalanimalguide.org/animals/common-garter-snake/
- **Last reviewed:** 2026-07-16

## Scientific classification

- **Kingdom:** Animalia
- **Phylum:** Chordata
- **Class:** Reptilia
- **Order:** Squamata
- **Family:** Colubridae
- **Genus:** Thamnophis

## Facts at a glance

| Attribute | Value |
| --- | --- |
| Scientific name | Thamnophis sirtalis |
| Diet | Carnivore (amphibians, fish, worms) |
| Habitat | Gardens, wetlands, meadows, and woodland edges |
| Lifespan | Around 8 years in the wild (varies by population and captivity). |
| Weight | About 0.15 kg typical adult mass (sex and region vary). |
| Top speed | Up to roughly 5 km/h when moving at speed. |
| Conservation status | Least Concern (IUCN) |

## Stripes and musk defence

Usually three light stripes on a darker body; pattern varies widely by subspecies. When seized they may musk foul-smelling cloacal fluid and rarely bite mildly — they are non-venomous to humans in any medically serious sense (some have mild saliva toxins irrelevant to people).

## Amphibians, fish, and earthworms

Diet includes frogs, salamanders, fish, leeches, and earthworms. Coastal populations famously eat toxic newts, sequestering toxins. Across its range it is tied to gardens, wetlands, meadows, and woodland edges, and field accounts emphasise this species’ distinctive ecology rather than generic habitat labels.

## Nearly continent-wide near water

Most of the United States and southern Canada except extreme Southwest deserts — gardens, wetlands, meadows, and woodland edges. Across its range it is tied to gardens, wetlands, meadows, and woodland edges, and field accounts emphasise this species’ distinctive ecology rather than generic habitat labels.

## Climate and wetland ally

Least Concern and adaptable. Narcisse Wildlife Management Area in Manitoba hosts enormous spring mating aggregations that draw tourists and need habitat protection.

## Frequently asked questions

### Are garter snakes poisonous?

They are not dangerous to healthy humans; bites may nick skin but lack medically significant venom for people.

### What is a garter snake mating ball?

In spring, dozens of males may swarm a single female emerging from hibernation — spectacular in places like Manitoba.

### Do garter snakes make good pest control?

They eat slugs, worms, and amphibians; they help in gardens without threatening people.

### Can garter snakes swim?

Yes — they swim well and often hunt in ponds and ditches.

### Where do common garter snakes live?

Across most of the United States and southern Canada in moist habitats.

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Source: Global Animal Guide (https://globalanimalguide.org/animals/common-garter-snake/). Licensed CC BY-NC 4.0 — free for non-commercial reuse with attribution.