Appearance
Eastern diamondback rattlesnakes are brown, yellow or tan with distinct black, brown and cream diamonds down their back. The species has a large, broad head with a dark stripe, outlined in white, that runs diagonally through the eyes to the neck. A thermal pit, which senses heat in their environment, is located between the eye and nostril. Their tails have a rattle that is made up of segments of keratin, and a new segment is added each time a snake sheds its skin. A commonly repeated myth is that you can age a snake by the number of rattle segments that it has, but this actually indicates how many times the snake has shed. Because rattles are brittle, it is not uncommon to see rattlesnakes with damaged or incomplete rattles.
The eastern diamondback rattlesnake is the largest rattlesnake species in the United States by length and weight. The average length of an adult is three to six feet, but individuals have been recorded to be more than 7 feet long, and their maximum length can reach 8 feet. The average weight of this species in Florida is around two to four pounds and some large individuals can weigh more than ten pounds. Males are typically larger than females. Neonates, or newly born snakes, are approximately 15 inches long when they are born, and their coloration and patterning resemble that of adults.
Behavior
Eastern diamondback rattlesnakes are solitary animals that are effective ambush predators. Since these snakes are cold-blooded, they bask in the sun to regulate their body temperatures. To avoid inclement weather, this species uses gopher tortoise burrows, armadillo holes, stump holes and root channels. These shelters keep them warm when air temperatures become too cold for surface activity. While foraging, rattlesnakes use vegetation for cover, relying on camouflage to conceal them. They are ambush predators, meaning they sit and wait in a coiled position for prey to cross their path. They use their thermal pits to help them locate warm-blooded prey. Once their prey is within range, the coiled snake can strike up to two-thirds its body length to inject its prey with venom. After striking, the snake lets the prey go and later follows the scent trail to track it down and eat it. These snakes mostly eat mammals such as mice, rabbits, rats, squirrels and occasionally eat ground-dwelling birds.
When camouflage fails and they feel threatened, the snake will begin to puff itself up to look larger and more intimidating. Eventually it may begin to rattle its tail to scare off the threat. Rattlesnakes, like many animals, would prefer to silently leave a dangerous situation. When given the opportunity, rattlesnakes will flee from human encounters. If a rattlesnake is ever observed in the wild it is best to give it space or let it slither away on its own.
Eastern diamondback rattlesnakes reach reproductive maturity between two and four years of age. Peak mating season occurs in late summer and fall. Occasionally, males will compete for females by participating in combat behavior. The winner of the match will get the opportunity to mate with the female while the loser flees, usually unharmed. In Florida, female rattlesnakes will give live birth to 8 to 29 young approximately six to seven months after mating. These snakes may live for more than 20 years; however, due to the threats they are facing in their environment, most rattlesnakes have shorter lifespans.
Habitat
Eastern diamondbacks are found throughout the southeastern United States. Their range includes eastern Louisiana, southern Mississippi, Alabama, Georgia, eastern South Carolina, southern North Carolina and all of Florida. Their primary habitat is longleaf pine savannas, and they will also use pine flatwoods, wiregrass areas and turkey oak habitats. They are capable of swimming and can be found on most barrier islands around Florida.
Rattlesnakes often rely on prescribed fires in their habitat. Fires help prevent the growth of oaks and other hardwood trees and promote the germination of pine trees and plants which allow for habitats like the long leaf pine savanna to flourish. Prescribed fires prevent habitat degradation and are an essential part of a healthy ecosystem.
Threats
Eastern diamondback rattlesnakes face a variety of threats, including:
- Habitat loss and alteration: human population growth has led to habitat loss as natural landscapes are converted to agricultural, commercial and residential areas. Their primary habitat, longleaf pine savannas, has been greatly reduced forcing them to use other habitats.
- Habitat degradation: without regular prescribed fires, habitat slowly degrades as hardwood tree species outcompete pine trees and cause forest succession. Eastern diamondback rattlesnakes rely on open pine forests for all stages of their lives.
- Road mortality: eastern diamondback rattlesnakes are vulnerable to being hit by cars as they crossroads.
- Disease: there are several diseases and parasites that can impact eastern diamondback rattlesnakes.
- Overexploitation: they are targeted by people for several reasons, including misunderstanding or fear of the species. Rattlesnake roundups had significant impacts to rattlesnakes and played a role in the decline of the species.
Conservation and Management
Eastern diamondback rattlesnakes are in decline throughout their range, including in Florida. However, there have been changes that are potentially going to benefit this species. For example, the majority of the rattlesnake roundup events that were held historically are now conservation festivals. These events help keep communities informed about why these snakes are beneficial. Current research of the species is focused on how they are affected by human behaviors, climate change and other environmental factors. Proper habitat management and restoration is beneficial for rattlesnakes. Restoring their habitat and maintaining it through prescribed fires will allow them to have a safe area to live, reproduce and forage.
How you can help
If you see one of these rattlesnakes, remember to give it space. These snakes should not be handled. If you live in an area where they are present, watch your step while outdoors and keep dogs on short leashes while walking through snake habitat. Be mindful walking around stumps, animal burrows and fallen trees, as rattlesnakes often use these habitat features for protection and foraging.
Report rattlesnake sightings or if you have questions about snake safety, please contact your FWC Regional Office.
Additional Information
Species Profile for Eastern Diamondback Rattlesnake
Florida Museum – Eastern Diamond-backed Rattlesnake
Smithsonian’s National Zoo & Conservation Biology Institute – Eastern Diamondback Rattlesnake
University of Georgia Savannah River Ecology Laboratory – Eastern Diamondback Rattlesnake