Pantherophis emoryi
Silhouette: Alex Slavenko · PhyloPic
In 3 days ~20% in a week ~40%
Pantherophis emoryi, commonly known as the Great Plains rat snake, is a species of nonvenomous rat snake in the family Colubridae. The species is native to the central part of the United States, from Missouri to Nebraska, to Colorado, south to Texas, and into northern Mexico.
The epithet, emoryi, is in honor of Brigadier General William Hemsley Emory, who was chief surveyor of the U.S. Boundary Survey team of 1852 and collected specimens for the Smithsonian Institution. As such, it is sometimes referred to as Emory's rat snake.
Additional common names for Pantherophis emoryi include the following: brown rat snake, chicken snake, eastern spotted snake, Emory's Coluber, Emory's pilot snake, Emory's racer, Emory's snake, gray rat snake, mouse snake, prairie rat snake, spotted mouse snake, Texas rat snake, and western pilot snake.
The Great Plains rat snake is typically light gray or tan in color, with dark gray, brown, or green-gray blotching down its back, and stripes on either side of the head which meet to form a point between the eyes. It is capable of growing to 3–5 feet (0.91–1.52 m) in total length (including tail). Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Padre Island National Seashore | 🇺🇸 United States | |
| 2 | Cumbres de Monterrey National Park | 🇲🇽 Mexico | |
| 3 | Big Bend National Park | 🇺🇸 United States |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Monterrey | 🇲🇽 México | |
| 2 | San Antonio | 🇺🇸 United States | |
| 3 | Austin | 🇺🇸 United States |
| # | Zoo / Centre | Country | |
|---|---|---|---|
| 1 | Dickerson Park Zoo | 🇺🇸 United States | |
| 2 | Wonders of Wildlife Museum & Aquarium | 🇺🇸 United States |
With luck
About 10% of wildlife watchers report a Great Plains Ratsnake sighting in Big Bend National Park on a given day, based on 10 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 37th 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.
June
In that month about 20% of wildlife watchers report a Great Plains Ratsnake in Big Bend National Park on a given day, against under 5% in July–October and December–March, the lowest months.
Between 8 and 11 pm
Across all the parks we cover, that three-hour window holds the most Great Plains Ratsnake sightings with a recorded time, and about half of them come between 6 pm and 6 am: it is seen both by day and at night.
Among the best
Of the 3 parks where we can rate Great Plains Ratsnake sightings, Big Bend National Park ranks 3rd at about 10%, level with the leaders once rounded. The best odds are in Padre Island National Seashore (United States, about 10%) and Cumbres de Monterrey National Park (Mexico, about 10%).
GBIF citizen-science records
It is estimated from how often the Great Plains Ratsnake is recorded against all the reptiles logged in Big Bend National Park (10 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.
