Thamnophis atratus
Silhouette: Alex Slavenko · PhyloPic
In 3 days ~10%
The aquatic garter snake (Thamnophis atratus) is a species of colubrid snake. Three subspecies are currently recognized. It is found exclusively along the coast of Oregon and California. The aquatic garter snake grows up to 18–40 inches (46–102 cm) long. Its dorsal coloration varies greatly. The different coloration patterns are: pale gray with alternating rows of darker blotches on the sides, dark brown with borders that are less distinct, or nearly all black. A long yellow stripe running down the back may be present or absent, only confined to the neck, or just very indistinct. The throat and underside of the snake are whitish to yellow.
One color morph of the aquatic garter snake has a blue-gray background color with a faint olive-colored dorsal stripe and white dots along its sides. Another color morph has a yellow dorsal stripe with black spots along its sides. The second color morph has the more classic garter snake look; however, due to its behavior and scalation, it is grouped in this species.
It can most commonly be found on the edges of bushlands, woodlands, grasslands, and forests near ponds, marshes, streams and lakes... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Redwood National Park | 🇺🇸 United States |
More parks will be added in future updates.
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | San Francisco | 🇺🇸 United States |
| # | Zoo / Centre | Country | |
|---|---|---|---|
| 1 | Lindsay Wildlife Experience | 🇺🇸 United States |
Rare
Under 5% of wildlife watchers report an Aquatic Garter Snake sighting in San Francisco on a given day, based on 12 verified sightings from GBIF citizen-science data. It is the 15th most-seen of the 21 reptiles we can rate there. Over three days the chance rises to about 10%, if each day is a fresh chance.
Any time of year
In every month with enough records, under 5% of wildlife watchers report an Aquatic Garter Snake in San Francisco on a given day, so our monthly data shows no clear season.
Between noon and 3 pm
Across all the parks we cover, that three-hour window holds the most Aquatic Garter Snake sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
Only San Francisco, in our data
San Francisco is the only city on Wallace's Line with enough records to rate Aquatic Garter Snake sightings: under 5% of wildlife watchers there report one on a given day.
GBIF citizen-science records
It is estimated from how often the Aquatic Garter Snake is recorded against all the reptiles logged in San Francisco (12 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.
