Coluber constrictor
Silhouette: Alex Slavenko · PhyloPic
In 3 days ~20% in a week ~30%
The eastern racer, or North American racer (Coluber constrictor), is a species of nonvenomous snake in the subfamily Colubrinae of the family Colubridae. The species is native to North America and Central America. Eleven subspecies, including the nominotypical subspecies, are recognized, which as a group are commonly referred to as the eastern racers. The species is monotypic in the genus Coluber.
Coluber constrictor is found throughout much of the United States, on both sides of the Rocky Mountains, but it also ranges north into Canada and south into Mexico, Guatemala, and Belize. Adult eastern racers can typically vary from 50 to 152 cm (20 to 60 in) in total length (tail included) depending on the subspecies, but a record-sized specimen measured 185.4 cm (73.0 in) in total length. A typical adult specimen will weigh around 556 g (1.226 lb), with little size difference between the sexes.
The patterns vary widely among subspecies. Most are solid-colored as their common names imply: black racers, brown racers, tan racers, blue racers, or green racers. "Runner" is sometimes used instead of "racer" in their common names. All... Wikipedia →
Recording0:08
United States · 2023
© Iñigo Javaloyes · iNaturalist · CC BY-NC 4.0
Recording0:11
United States · 2025
© Kelsey Proffitt Art · iNaturalist · CC BY-NC 4.0
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Everglades National Park | 🇺🇸 United States | |
| 2 | Big Cypress National Preserve | 🇺🇸 United States | |
| 3 | Congaree National Park | 🇺🇸 United States | |
| 4 | Badlands National Park | 🇺🇸 United States | |
| 5 | Merritt Island National Wildlife Refuge | 🇺🇸 United States | |
| 6 | Great Smoky Mountains National Park | 🇺🇸 United States | |
| 7 | Redwood National Park | 🇺🇸 United States | |
| 8 | Shenandoah National Park | 🇺🇸 United States | |
| 9 | Channel Islands National Park | 🇺🇸 United States | |
| 10 | Yosemite National Park | 🇺🇸 United States | |
| 11 | Cumbres de Monterrey National Park | 🇲🇽 Mexico |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Orlando | 🇺🇸 United States | |
| 2 | Miami | 🇺🇸 United States | |
| 3 | Denver | 🇺🇸 United States | |
| 4 | Austin | 🇺🇸 United States | |
| 5 | Washington | 🇺🇸 United States | |
| 6 | Dallas | 🇺🇸 United States | |
| 7 | Houston | 🇺🇸 United States | |
| 8 | Salt Lake City | 🇺🇸 United States | |
| 9 | Baltimore | 🇺🇸 United States | |
| 10 | Philadelphia | 🇺🇸 United States |
| # | Zoo / Centre | Country | |
|---|---|---|---|
| 1 | Cincinnati Zoo and Botanical Garden | 🇺🇸 United States | |
| 2 | Virginia Zoological Park | 🇺🇸 United States | |
| 3 | Reptile Gardens | 🇺🇸 United States |
With luck
About 10% of wildlife watchers report a North American Racer sighting in Cumbres de Monterrey National Park on a given day, based on 10 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 30th most-seen of the 43 reptiles we can rate there. Over three days the chance rises to about 20%, and over a week to about 30%, if each day is a fresh chance.
May to October
In those months about 10% of wildlife watchers report a North American Racer in Cumbres de Monterrey National Park on a given day, against under 5% in November to April, the lowest months. Those are among Cumbres de Monterrey National Park's wettest months, with about 130 mm of rain a month against 20 mm in December.
Between 11 am and 2 pm
Across all the parks we cover, that three-hour window holds the most North American Racer sightings with a recorded time, and about 8 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
11th of 11
Of the 11 parks where we can rate North American Racer sightings, Cumbres de Monterrey National Park ranks 11th at about 10%. The best odds are in Everglades National Park (United States, about 40%), Big Cypress National Preserve (United States, about 40%) and Congaree National Park (United States, about 40%).
Same family: Colubridae
The closest relatives of the North American Racer that you can see in Cumbres de Monterrey National Park (family Colubridae, Colubrid Snakes) are Northern Cat-eyed Snake (about 10%), Baird's Ratsnake (about 10%) and Great Plains Ratsnake (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the North American Racer is recorded against all the reptiles logged in Cumbres de Monterrey 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.
