Common Garter Snake

Common Garter Snake

Thamnophis sirtalis

Silhouette: Alex Slavenko · PhyloPic

Least ConcernNear ThreatenedVulnerableEndangeredCritically Endangered
Daily sighting probability ~60% · Likely
at Isle Royale National Park
88 Verified sightings at Isle Royale National Park From 2019 to 2026
1,639 Verified sightings across all 11 parks From 2019 to 2026
August Best month highest sighting rate
☀️ Diurnal When it's spotted during daytime hours (6am–6pm)

About the Common Garter Snake

The common garter snake (Thamnophis sirtalis) is a species of snake in the subfamily Natricinae of the family Colubridae. The species is indigenous to North America and found widely across the continent. There are several recognized subspecies. Most common garter snakes have a pattern of yellow stripes on a black, brown or green background, and their average total length (including tail) is about 55 cm (22 in), with a maximum total length of about 137 cm (54 in). The average body mass is 150 g (5.3 oz). The common garter snake is the state reptile of Massachusetts.

The subspecific name fitchi is in honor of the American herpetologist Henry Sheldon Fitch. The subspecific name pickeringii is in honor of the American naturalist Charles E. Pickering. Current scientific classification recognizes 12 subspecies (ordered by date):

A trinomial authority in parentheses indicates that the subspecies was originally described in a genus other than Thamnophis. Common garter snakes are thin snakes. Few grow over about 4 ft (1.2 m) long, and most stay smaller. Most have longitudinal stripes in many different colors. Common... Wikipedia →

Global Distribution

Warmer areas are where this animal is recorded most often.

Parks Where Found

# Park Country Daily sighting probability
1 Wood Buffalo National Park 🇨🇦 Canada
~80%
2 Cape Breton Highlands National Park 🇨🇦 Canada
~70%
3 Isle Royale National Park 🇺🇸 United States
~60%
4 Point Pelee National Park 🇨🇦 Canada
~60%
5 Acadia National Park 🇺🇸 United States
~50%
6 Shenandoah National Park 🇺🇸 United States
~40%
7 Big Cypress National Preserve 🇺🇸 United States
~20%
8 Congaree National Park 🇺🇸 United States
~20%
9 Everglades National Park 🇺🇸 United States
~10%
10 Yosemite National Park 🇺🇸 United States
~10%
11 Gros Morne National Park 🇨🇦 Canada
Insufficient data

Quick answers

What are the chances of seeing a Common Garter Snake in Isle Royale National Park?

About 60% of wildlife watchers report a Common Garter Snake sighting in Isle Royale National Park, based on 88 verified sightings from GBIF citizen-science data.

When is the best time to see Common Garter Snake in Isle Royale National Park?

August has the highest sighting rate for Common Garter Snake in Isle Royale National Park in our monthly data.

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