The largest rattlesnake in the world is the Eastern Diamondback Rattlesnake, scientifically known as Crotalus adamanteus. This species is the longest and heaviest venomous snake in North America. Rattlesnakes are New World pit vipers, characterized by heat-sensing pits located between the eye and the nostril. They belong to the genera Crotalus and Sistrurus and are instantly recognizable by the keratinous rattle segments at the end of their tail.
Identifying the Largest Species
The Eastern Diamondback Rattlesnake is distinguished by its sheer size and striking dorsal pattern. Its name references the series of dark, brown to black diamonds that run along the center of its back. These diamond shapes often have a lighter center and are sharply outlined by cream or yellowish scales, creating a highly contrasting appearance.
The snake’s coloration is generally a mix of olive green, brownish-yellow, or muddy gray, which provides excellent camouflage within its native habitat. A distinct feature is the dark band that extends diagonally backward from the eye, bordered by two pale lines, which helps to obscure the eye’s location.
Measuring Record Size and Average Dimensions
The Eastern Diamondback Rattlesnake is primarily considered the largest due to its impressive mass and girth. Most adult specimens typically measure between 3.5 to 5.5 feet (1.1 to 1.7 meters) in total length. These average-sized adults usually weigh around 5 to 6 pounds, making them heavy-bodied snakes for their length.
Significantly larger individuals have been documented, with some reliably reported to reach lengths exceeding 6 feet. The historical maximum recorded length for the species is cited as being near 8 feet (2.4 meters), though these extreme measurements are rare and sometimes lack precise scientific documentation. A specimen shot in 1946 measured 7.8 feet and weighed a massive 34 pounds (15.4 kg), illustrating the species’ potential for bulk. Weight can fluctuate significantly depending on a snake’s recent feeding, but a healthy, mature male can easily exceed 10 to 15 pounds.
Geographical Range and Habitat
The range of the Eastern Diamondback Rattlesnake is confined to the Coastal Plain of the Southeastern United States. This distribution extends from the southern coastal regions of North Carolina, south through all of Florida, and west into parts of coastal Mississippi and eastern Louisiana. The species thrives in environments characterized by sandy, dry conditions with open canopies.
Its preferred habitats include longleaf pine flatwoods, sandhills, maritime forests, and coastal scrub. The snakes frequently utilize the burrows of gopher tortoises (Gopherus polyphemus) and other subterranean cavities for shelter from temperature extremes and fire.
Other Large Rattlesnake Species
While the Eastern Diamondback holds the record for overall size and mass, other species are large. The Western Diamondback Rattlesnake (Crotalus atrox) is a geographically widespread species found throughout the Southwestern United States and Mexico.
The Western Diamondback can reach lengths of nearly 7 feet, though its average adult length is closer to 3 to 5 feet. It is generally a more slender snake compared to its eastern cousin; while some individuals may approach the Eastern Diamondback in length, they do not typically rival it in terms of weight and bulk. The Timber Rattlesnake (Crotalus horridus) is another large species that can reach lengths of up to 6 feet, but it is less massive than the Eastern Diamondback.