Crotalus lepidus
Silhouette: Bill Bouton (source photo) & T. Michael Keesey (vectorization) · PhyloPic
In 3 days ~20% in a week ~40%
Crotalus lepidus is a venomous pit viper species found in the southwestern United States and northern central Mexico. Four subspecies are currently recognized, including the nominate subspecies described here. This small species rarely exceeds 32 in (81.3 cm) in length. It has a large, rounded head, and fairly heavy body for its size, with eyes with vertical pupils. Like other rattlesnakes, its tail has a rattle, which is composed of keratin. Each time the snake sheds its skin, a new segment is added to the rattle. However, the rattle is fragile and may break off, and the frequency of shedding can vary. So, the snake's age cannot be determined by the number of segments or length of the rattle.
The color pattern varies greatly, but generally reflects the color of the rock in the snake's natural environment. Snakes found near areas of predominantly limestone tend to be a light grey in color, with darker grey banding. Snakes found at higher altitudes have darker colors. Specimens of the mottled rock rattlesnake (C. l. lepidus) from the Davis Mountains region often exhibit a more pink coloration, with dark-grey speckling rather than distinct banding.[1] The banded rock... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Guadalupe Mountains National Park | 🇺🇸 United States | |
| 2 | Big Bend National Park | 🇺🇸 United States | |
| 3 | Cumbres de Monterrey National Park | 🇲🇽 Mexico |
| # | Zoo / Centre | Country | |
|---|---|---|---|
| 1 | San Diego Zoo | 🇺🇸 United States | |
| 2 | Columbus Zoo and Aquarium | 🇺🇸 United States | |
| 3 | Ecological Center of Sonora | 🇲🇽 Mexico | |
| 4 | Sedgwick County Zoo | 🇺🇸 United States | |
| 5 | Los Angeles Zoo | 🇺🇸 United States | |
| 6 | Phoenix Zoo | 🇺🇸 United States | |
| 7 | Cape May County Park & Zoo | 🇺🇸 United States | |
| 8 | Louisville Zoo | 🇺🇸 United States | |
| 9 | Saint Louis Zoo | 🇺🇸 United States | |
| 10 | Dickerson Park Zoo | 🇺🇸 United States | |
| 11 | Indianapolis Zoo | 🇺🇸 United States | |
| 12 | Zoo Knoxville | 🇺🇸 United States | |
| 13 | Virginia Zoological Park | 🇺🇸 United States | |
| 14 | Houston Zoo | 🇺🇸 United States | |
| 15 | Arizona-Sonora Desert Museum | 🇺🇸 United States | |
| 16 | Melbourne Zoo | 🇦🇺 Australia | |
| 17 | ABQ BioPark Zoo | 🇺🇸 United States | |
| 18 | San Antonio Zoo | 🇺🇸 United States | |
| 19 | Cameron Park Zoo | 🇺🇸 United States | |
| 20 | Philadelphia Zoo | 🇺🇸 United States | |
| 21 | Zoo Atlanta | 🇺🇸 United States | |
| 22 | Hogle Zoo | 🇺🇸 United States | |
| 23 | Little Rock Zoo | 🇺🇸 United States | |
| 24 | Reptile Gardens | 🇺🇸 United States | |
| 25 | Chattanooga Zoo at Warner Park | 🇺🇸 United States |
With luck
About 10% of wildlife watchers report a Rock Rattlesnake 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 and July
In those months about 20% of wildlife watchers report a Rock Rattlesnake in Big Bend National Park on a given day, against under 5% in August and November–March, the lowest months.
Between 10 am and 1 pm
Across all the parks we cover, that three-hour window holds the most Rock Rattlesnake sightings with a recorded time, and about 6 in 10 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 Rock Rattlesnake sightings, Big Bend National Park ranks 2nd at about 10%. The best odds are in Guadalupe Mountains National Park (United States, about 20%).
Same genus: Crotalus
The closest relatives of the Rock Rattlesnake that you can see in Big Bend National Park (genus Crotalus, Rattlesnakes) are Western Diamondback Rattlesnake (about 40%), Eastern Black-tailed Rattlesnake (about 30%) and Mohave Rattlesnake (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Rock Rattlesnake 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.
