Crotalus adamanteus
Silhouette: Bill Bouton (source photo) & T. Michael Keesey (vectorization) · PhyloPic
In 3 days ~60% in a week ~90%
The eastern diamondback rattlesnake (Crotalus adamanteus) is a species of pit viper in the family Viperidae. The species is endemic to the Southeastern United States. It is the largest rattlesnake species and one of the heaviest venomous snakes in the Americas. No subspecies are recognized.
The eastern diamondback rattlesnake is the largest rattlesnake species and is one of the heaviest known species of venomous snake, with one specimen shot in 1946 measuring 2.4 m (7.8 ft) in length and weighing 15.4 kg (34 lb). However, other venomous snakes may rival this species in weight such as the much longer but more slender king cobra and the shorter but even bulkier Gaboon viper. Maximum reported lengths for the eastern diamondback rattlesnake are 2.4 m (8 ft) and 2.5 m (8.25 ft). However, the stated maximum sizes have been called into question due to a lack of voucher specimens. Demonstrating rare reverse sexual size dimorphism, males are typically larger than females.
Specimens over 2.1 m (7 ft) are rare, but well documented. Klauber (1998) included a letter he received from E. Ross Allen in 1953, in which Allen explains how for years he offered a reward of $100, and later... Wikipedia →
Recording0:04
United States · 2026
© rbbirdss · iNaturalist · CC BY-NC 4.0
Recording0:11
United States · 2023
© eando0923 · iNaturalist · CC BY-NC 4.0
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Big Cypress National Preserve | 🇺🇸 United States | |
| 2 | Everglades National Park | 🇺🇸 United States | |
| 3 | Merritt Island National Wildlife Refuge | 🇺🇸 United States |
| # | Zoo / Centre | Country | |
|---|---|---|---|
| 1 | Disney's Animal Kingdom | 🇺🇸 United States | |
| 2 | Busch Gardens Tampa | 🇺🇸 United States | |
| 3 | San Diego Zoo | 🇺🇸 United States | |
| 4 | Prague Zoo | 🇨🇿 Czechia | |
| 5 | National Zoological Park | 🇺🇸 United States | |
| 6 | Denver Zoo | 🇺🇸 United States | |
| 7 | Skansen | 🇸🇪 Sweden | |
| 8 | Cincinnati Zoo and Botanical Garden | 🇺🇸 United States | |
| 9 | California Academy of Sciences | 🇺🇸 United States | |
| 10 | Australia Zoo | 🇦🇺 Australia | |
| 11 | Greensboro Science Center | 🇺🇸 United States | |
| 12 | Lion Country Safari | 🇺🇸 United States | |
| 13 | Columbus Zoo and Aquarium | 🇺🇸 United States | |
| 14 | Bronx Zoo | 🇺🇸 United States | |
| 15 | Dallas Zoo | 🇺🇸 United States | |
| 16 | Jacksonville Zoo and Gardens | 🇺🇸 United States | |
| 17 | Central Florida Zoo and Botanical Gardens | 🇺🇸 United States | |
| 18 | Birmingham Zoo | 🇺🇸 United States | |
| 19 | Louisville Zoo | 🇺🇸 United States | |
| 20 | Guadalajara Zoo | 🇲🇽 Mexico | |
| 21 | Oklahoma City Zoo and Botanical Garden | 🇺🇸 United States | |
| 22 | Saint Louis Zoo | 🇺🇸 United States | |
| 23 | Night Safari | 🇸🇬 Singapore | |
| 24 | ZooTampa | 🇺🇸 United States | |
| 25 | Fort Worth Zoo | 🇺🇸 United States | |
| 26 | Taronga Zoo | 🇦🇺 Australia | |
| 27 | Singapore Zoo | 🇸🇬 Singapore | |
| 28 | Houston Zoo | 🇺🇸 United States | |
| 29 | Melbourne Zoo | 🇦🇺 Australia | |
| 30 | Philadelphia Zoo | 🇺🇸 United States | |
| 31 | Budapest Zoo & Botanical Garden | 🇭🇺 Hungary | |
| 32 | Faunia | 🇪🇸 Spain | |
| 33 | Pittsburgh Zoo & Aquarium | 🇺🇸 United States | |
| 34 | Riverbanks Zoo | 🇺🇸 United States | |
| 35 | Buffalo Zoo | 🇺🇸 United States | |
| 36 | River Wonders | 🇸🇬 Singapore | |
| 37 | Parc Jardins du Monde | 🇫🇷 France | |
| 38 | Henry Vilas Zoo | 🇺🇸 United States | |
| 39 | Safari Masai Mara | 🇲🇽 Mexico | |
| 40 | Alligator Adventure | 🇺🇸 United States | |
| 41 | Reptile Gardens | 🇺🇸 United States | |
| 42 | ZooAmerica | 🇺🇸 United States | |
| 43 | Greenville Zoo | 🇺🇸 United States | |
| 44 | Santa Fe College Teaching Zoo | 🇺🇸 United States | |
| 45 | Staten Island Zoo | 🇺🇸 United States | |
| 46 | Gulfarium Marine Adventure Park | 🇺🇸 United States | |
| 47 | Clyde Peeling's Reptiland | 🇺🇸 United States | |
| 48 | North Carolina Aquarium at Pine Knoll Shores | 🇺🇸 United States | |
| 49 | South Carolina Aquarium | 🇺🇸 United States | |
| 50 | Baltic Sea Science Center | 🇸🇪 Sweden |
Possible
About 30% of wildlife watchers report an Eastern Diamondback Rattlesnake sighting in Everglades National Park on a given day, based on 244 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 15th most-seen of the 54 reptiles we can rate there. Over three days the chance rises to about 60%, and over a week to about 90%, if each day is a fresh chance.
September–October and December
In those months about 40% of wildlife watchers report an Eastern Diamondback Rattlesnake in Everglades National Park on a given day, against about 20% in June to August, the lowest months.
Between 4 and 7 pm
Across all the parks we cover, that three-hour window holds the most Eastern Diamondback Rattlesnake sightings with a recorded time, and about 7 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
Among the best
Of the 3 parks where we can rate Eastern Diamondback Rattlesnake sightings, Everglades National Park ranks 2nd at about 30%, level with the leaders once rounded. The best odds are in Big Cypress National Preserve (United States, about 30%).
Same family: Viperidae
The closest relatives of the Eastern Diamondback Rattlesnake that you can see in Everglades National Park (family Viperidae, Vipers) are Florida Cottonmouth (about 50%) and Pygmy Rattlesnake (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Eastern Diamondback Rattlesnake is recorded against all the reptiles logged in Everglades National Park (244 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.
