All rattlesnakes are venomous vipers in the family Viperidae. There are around 30 species of rattlesnake, divided between the Crotalus and Sistrurus genera. The largest rattlesnakes belong to the Crotalus genus, characterized by heavier bodies and larger rattles than their Sistrurus cousins. Rattlesnakes are endemic to the Americas and can be found from Canada to Argentina, including nearly every region in the U.S. Rattlesnakes are the largest venomous snakes on the continent, but exactly how large do they get? Read on to learn the size of the average rattlesnake and discover the largest rattlesnake ever recorded.
How Big Do Rattlesnakes Get?
Western diamondback rattlesnakes are common across the southwestern U.S.
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Among over 30 species of rattlesnake, there is a wide variety of sizes. The smallest rattlesnake species is the western pygmy rattlesnake (Sistrurus miliarius), which only reaches about 18 inches in length. The largest rattlesnakes are the eastern diamondbacks (Crotalus adamanteus), which can reach a maximum of around 8 feet long. Most rattlesnakes, however, fall somewhere between 2-4 feet long, with the average eastern diamondback growing from 3-6 feet long.
Rattlesnakes also vary significantly in weight. Lightweight rattlesnakes such as the ridge-nosed rattlesnake (Crotalus willardi) weigh only 3 to 4 ounces. The eastern diamondback is also the heaviest rattlesnake, typically weighing between 4 and 10 pounds. However, some large animals can weigh up to upwards of 20 pounds.
Rattlesnake Rumors
Over the years, there have been a number of incredible claims about enormous rattlesnakes over 10 feet long. However, these claims are unsubstantiated, and some are outright hoaxes. There are only four species believed to reach lengths of 6-7 feet, let alone larger. Eastern diamondbacks, western diamondbacks (Crotalus atrox), timber rattlesnakes (Crotalus horridus), and Mexican west coast rattlesnakes (Crotalus basiliscus) have only rarely been reported exceeding 6 feet in length.
Exceptionally large rattlesnakes are so rare that some institutions have even offered a reward for a live, 8-foot rattlesnake. For example, Reptile Gardens in South Dakota has had a standing offer for an 8-foot rattlesnake since the 1950s. The dollar amount has regularly increased over time, but the reward has never been paid out.
Record-Breaking Rattlesnakes
The eastern diamondback rattlesnake is the largest rattlesnake species, reaching up to 8 feet in length.
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Since eastern diamondback rattlesnakes are the largest species, it comes as no surprise that the largest rattlesnake ever recorded is an eastern diamondback that was caught in 1946. According to Guinness World Records, this impressive snake was 7 feet and 9 inches long, which is about the size of a standard home pool table or the bed of a long bed pickup truck. The official record also notes this snake weighed 34 pounds. There is no information regarding where the snake was caught, but eastern diamondback rattlesnakes are only found in the southeastern U.S. Although this snake may hold the official world record, it is not the largest rattlesnake ever documented.
Herpetologist, author, and curator of reptiles at the Bronx Zoo, Dr. Raymond Lee Ditmars, discusses an even larger rattlesnake in his 1915 book, “The Reptile Book: A Comprehensive Popularised Work on the Structure and Habits of the Turtles, Tortoises, Crocodilians, Lizards and Snakes Which Inhabit the United States and Northern Mexico.” Referring to the eastern diamondback rattlesnake, on page 477, he writes, “The largest specimen measured by the writer was eight feet, three inches in length.” Ditmars goes on to state that the snake was 4.5 inches in diameter and that the head was 3.25 inches wide. No weight was given, but the author notes that this massive snake was captured in the central part of Florida.
The Largest Rattlesnake Born in Captivity
Albino rattlesnakes have red eyes and pale, often white or yellow, coloration.
Edgar, an albino eastern diamondback rattlesnake, is believed to hold the record for the largest rattlesnake born in captivity. He grew to 7 feet and 4 inches in length, which is longer than a king-size bed. He was also a heavy snake, weighing nearly 20 pounds. Edgar was born at the Central Florida Zoo in 2001. He lived at the zoo’s partner organization, the Orianne Center for Indigo Conservation, until his death in 2023.
Edgar was special not only because of his large size, but also because of his albinism. Instead of the typical eastern diamondback’s brown, tan, black, and cream coloring, albino eastern diamondbacks have pale, white or yellow bodies and red eyes. Albino snakes are extremely rare in the wild, as their inability to camouflage makes them more vulnerable to predators. Edgar’s long life is largely attributed to the excellent care he received in captivity. The lifespan of a typical eastern diamondback in the wild is up to 15 years, with albinos living even shorter lives due to their lack of protective coloring.
