Plains Garter Snake

Plains Garter Snake

Thamnophis radix

Silhouette: Alex Slavenko · PhyloPic

LCLeast ConcernNTVUENCR
Daily sighting probability ~20% · Possible
at Denver

In 3 days ~40% in a week ~70%

158 Verified sightings at Denver
155 In all 3 parks From 2019 to 2026
June Best month
☀️ Diurnal When it's spotted

About the Plains Garter Snake

The plains garter snake (Thamnophis radix) is a species of garter snake native to most of the central United States as far north as Canada and as far south as Texas. It has a distinctive orange or yellow stripe from its head to tail, and the rest of its body is mainly a gray-green color. The snake is commonly found living near water sources such as streams and ponds, but can also be found in urban areas and vacant lots. Although the IUCN lists the species as "Least Concern", some states have given it their own special status. This species is mildly venomous, although the venom is not toxic to humans.

The plains garter snake has either an orange or yellow stripe down its back and distinctive black bars on its lip. The stripe normally starts at the head and continues all the way to the tail tip. Lateral stripes are located on the third and fourth scale rows and are normally a greenish-yellow color. Its belly is gray-green with small dark spots along the edges. Most have distinctive light yellow spots on the top of the head. The snake is described as medium-sized and is on average around 3 ft (0.91 m).

Described as "one of the most cold... Wikipedia →

Global Distribution

Parks Where Found

# Park Country Daily sighting probability
1 Elk Island National Park 🇨🇦 Canada
~50%
2 Riding Mountain National Park 🇨🇦 Canada
~30%
3 Badlands National Park 🇺🇸 United States
~20%

Cities Where Found

# City Country Daily sighting probability
1 Denver 🇺🇸 United States
~20%
2 Chicago 🇺🇸 United States
~10%
3 Edmonton 🇨🇦 Canada
<5%
4 Minneapolis [Saint Paul] 🇺🇸 United States
<5%

Zoos & Centres Where Found

# Zoo / Centre Country
1 Columbus Zoo and Aquarium 🇺🇸 United States In captivity
2 Brookfield Zoo 🇺🇸 United States In captivity

Before you go

What are the chances of seeing a Plains Garter Snake in Denver?

Possible

About 20% of wildlife watchers report a Plains Garter Snake sighting in Denver on a given day, based on 158 verified sightings from GBIF citizen-science data. It is the 6th most-seen of the 12 reptiles we can rate there. Over three days the chance rises to about 40%, and over a week to about 70%, if each day is a fresh chance.

When is the best time to see a Plains Garter Snake in Denver?

May to October

In those months about 20% of wildlife watchers report a Plains Garter Snake in Denver on a given day, against under 5% in January and February, the lowest months.

What time of day is best to see a Plains Garter Snake?

Between 11 am and 2 pm

Across all the parks we cover, that three-hour window holds the most Plains Garter Snake sightings with a recorded time, and about 8 in 10 of them come between 6 am and 6 pm: it is a daytime animal.

Is Denver the best place to see a Plains Garter Snake?

Yes

Of the 4 cities where we can rate Plains Garter Snake sightings, Denver has the highest daily chance: about 20%. Next come Chicago (United States, about 10%) and Edmonton (Canada, under 5%).

Where does the Plains Garter Snake sighting chance come from?

GBIF citizen-science records

It is estimated from how often the Plains Garter Snake is recorded against all the reptiles logged in Denver (158 verified sightings), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.

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