● Venomous · Native to the United States

Eastern diamondback rattlesnake

Crotalus adamanteus (Palisot de Beauvois, 1799)

Also called eastern diamond-backed rattlesnake
Data updated October 2026

Eastern diamondback rattlesnake stretched across pine needles, showing dark diamonds outlined in cream and yellow
Fig. 1 — Adult in a pine savanna, showing the dark, cream-edged diamonds along the back.
Close view of an eastern diamondback rattlesnake's broad head with a pale-bordered dark stripe through the eye
Fig. 2 — A dark stripe edged in pale scales runs from the eye toward the jaw.

At a glance

The longest and heaviest rattlesnake in the United States, found in the pine savannas and flatwoods of the Southeast and throughout Florida. It is not aggressive toward people and usually stays still or slips away. It is declining across its range.

01

Identification

A very heavy-bodied snake with a bold chain of dark brown or black diamonds down the back, each diamond outlined in cream or yellow, over a brown, olive, yellow or tan body. The broad, triangular head carries a dark stripe, outlined in white, running from the eye back toward the neck, which gives the face a masked look. The tail ends in a rattle; newborns have only a single button.

  1. 01Cream-edged diamonds. Dark diamonds with cream or yellow borders run the full length of the back.
  2. 02Masked face. A dark band through the eye, outlined in white or cream, runs back toward the neck.
  3. 03Size and pit viper features. A thick body, a rattle, a heat-sensing pit between eye and nostril and vertical pupils.

Commonly confused with

02

Size

01 ft2 ft3 ft4 ft5 ft6 ft Typical adult · about 4.5 ft (137 cm)

Most adults measure 3 to 6 feet (91–183 cm). Some exceed 7 feet, and the maximum is about 8 feet. Florida adults typically weigh 2 to 4 pounds, while large snakes can top 10 pounds. Males usually grow larger than females. Newborns are about 15 inches (38 cm) long.

03

Range & habitat

Eastern diamondback rattlesnake near a gopher tortoise burrow in an open longleaf pine savanna
Fig. 3 — Open, fire-maintained pine savanna with burrows for shelter is prime habitat.

Eastern diamondbacks live only in the far southeastern United States. The historic range followed the pine savannas of the Coastal Plain from southeastern North Carolina through Florida and west to eastern Louisiana. Today they are gone or nearly gone from Louisiana and North Carolina, and the largest populations are in Florida and Georgia. They occur throughout Florida, swim well and live on many barrier islands. Prime habitat is open longleaf pine savanna with grassy ground cover, along with pine flatwoods, sandhills, scrub, palmetto and wiregrass flats and coastal dunes. Gopher tortoise and armadillo burrows, stump holes and root channels provide shelter. These habitats depend on regular fire to stay open.

State guides: Florida

04

Diet & predators

This is an ambush hunter that may wait coiled for days beside a log, palmetto clump or small-mammal trail. It finds warm-blooded prey by scent and with its heat-sensing pits, strikes, then lets go and follows the scent trail to the dying animal. Cotton rats, mice, rats, squirrels and rabbits make up most of the diet, with an occasional ground-dwelling bird.

Feeds on

  • Cotton rats and mice
  • Rabbits
  • Squirrels, including fox squirrels
  • Ground-dwelling birds

Preyed on by

  • Hawks and eagles
  • Other snakes
  • Predatory mammals
  • Adults have few predators; young are most at risk
Hispid cotton rat in grass
Prey — cotton rats.
Red-tailed hawk perched on a branch
Predator — hawks.

05

Behavior & seasons

Eastern diamondbacks are solitary and not aggressive toward people. When encountered they usually stay still and rely on camouflage, or slip away quietly. If they cannot escape they may puff up to look bigger and rattle. They move little day to day, often 30 feet or less, though males roam more widely in the breeding season. In summer they travel mostly in the morning and evening. Males sometimes wrestle each other for access to females.

They are active for at least seven to eight months a year and almost year-round in south Florida. In cold weather they shelter in stump holes and in the burrows of gopher tortoises, armadillos and woodrats. Adults are strongly tied to their home ranges, about 200 acres for males and 50 to 75 acres for females.

06

Reproduction

Eastern diamondbacks bear live young. Most mating happens in late summer and fall, with some in spring; females can store sperm over winter and give birth the following August or September, often near large fallen logs or in burrows. Litters range from 8 to 29 young and average about 10 to 14. Females usually breed only every two to three years, and although some can reproduce at age three, many do not start until 7 to 10 years old. They can live more than 20 years in the wild.

07

Conservation

The eastern diamondback is declining throughout its range, including Florida. It is not federally listed, but the U.S. Fish and Wildlife Service has reviewed it for listing under the Endangered Species Act, and North Carolina lists it as endangered. Only a small fraction of the original longleaf pine habitat remains. Development, fire suppression, road deaths (especially of males searching for mates), collection and deliberate killing, including at past rattlesnake roundups, are the main threats. Slow breeding means losses take a long time to recover.

08 — Bite safety

If someone is bitten

Eastern diamondback bites are a medical emergency. Every bite needs medical care. Call 911 or go to the nearest emergency department. For guidance, call Poison Control at 1-800-222-1222. If a pet is bitten, take it to a veterinarian right away.

This page does not give first-aid or treatment instructions. Read our safety disclaimer.

Keep reading

Sources

Data updated October 2026 · How we build these pages