Thamnophis marcianus
Silhouette: Alex Slavenko · PhyloPic
In 3 days ~20% in a week ~40%
The checkered garter snake (Thamnophis marcianus) is a species of garter snake in the subfamily Natricinae of the family Colubridae. The species is native to the southwestern United States, Mexico, and Central America. There are two recognized subspecies.
The specific epithet marcianus is in honor of American Brigadier General Randolph B. Marcy, who led surveying expeditions to the frontier areas in the mid-19th century. The checkered garter snake is typically greenish in color, with a distinct, black checkerboard pattern down its back. It is capable of growing to a total length (tail included) of 42 inches (107 cm), but is usually 18 to 24 inches (46 to 61 cm).
The preferred natural habitats of Thamnophis marcianus are desert, grassland, shrubland, and forest, usually close to water, at altitudes from sea level to 2,200 m (7,200 ft). The diet of Thamnophis marcianus includes small frogs, toads, small fish, and earthworms. If kept as a pet, it can be trained on live or freeze-thawed mice, but even so, it is a fussy eater and can suddenly start to refuse mice at any point.
Unlike most garter snakes, the checkered... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Padre Island National Seashore | 🇺🇸 United States | |
| 2 | Big Bend National Park | 🇺🇸 United States | |
| 3 | Saguaro National Park | 🇺🇸 United States |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | San Antonio | 🇺🇸 United States | |
| 2 | Austin | 🇺🇸 United States | |
| 3 | Monterrey | 🇲🇽 México |
| # | Zoo / Centre | Country | |
|---|---|---|---|
| 1 | Phoenix Zoo | 🇺🇸 United States | |
| 2 | Silesian Zoological Garden | 🇵🇱 Poland | |
| 3 | Warsaw Zoo | 🇵🇱 Poland | |
| 4 | Wrocław Zoological Garden | 🇵🇱 Poland | |
| 5 | Parque museo La Venta | 🇲🇽 Mexico | |
| 6 | Africarium | 🇵🇱 Poland | |
| 7 | Children's Aquarium at Fair Park | 🇺🇸 United States | |
| 8 | herpetarium warszawskiego ZOO | 🇵🇱 Poland | |
| 9 | hipopotamiarnia i akwarium morskie warszawskiego ZOO | 🇵🇱 Poland | |
| 10 | terrarium ogrodu zoologicznego we Wrocławiu | 🇵🇱 Poland |
With luck
About 10% of wildlife watchers report a Checkered Garter Snake sighting in Big Bend National Park on a given day, based on 9 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 41st most-seen of the 48 reptiles we can rate there. Over three days the chance rises to about 20%, and over a week to about 40%, if each day is a fresh chance.
September
In that month about 20% of wildlife watchers report a Checkered Garter Snake in Big Bend National Park on a given day, against under 5% in June, August, October and December–February, the lowest months. That is one of Big Bend National Park's wettest months, with about 50 mm of rain against 10 mm in April.
Between 8 and 11 pm
Across all the parks we cover, that three-hour window holds the most Checkered Garter Snake sightings with a recorded time, and about half of them come between 6 am and 6 pm: it is seen both by day and at night.
2nd of 3
Of the 3 parks where we can rate Checkered Garter Snake sightings, Big Bend National Park ranks 2nd at about 10%. The best odds are in Padre Island National Seashore (United States, about 30%).
GBIF citizen-science records
It is estimated from how often the Checkered Garter Snake is recorded against all the reptiles logged in Big Bend National Park (9 verified sightings from 2019 to 2026), 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.
