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Eastern Diamondback Rattlesnake

Facts about the Eastern Diamondback Rattlesnake from the printable Fact Sheet  

Species Description

Eastern diamondback rattlesnakes are the largest rattlesnakes in the world, possibly measuring up to 243.84 cm (8 feet) in total length and 7 kg (15.43 pounds) in weight. Adults are typically 100-150 cm (3 feet 3.37 inches to 4 feet 11 inches) and weigh 1.8-2.3 kg (3.97-5.07 pounds). This species is sexually dimorphic in size with males attaining greater lengths than females. Juveniles range from 30-46 cm (11.81 inches to 1 foot 6 inches) at birth.

Eastern diamondback rattlesnakes easily identified by the pattern of dark brown to black diamonds, bordered with a cream to yellow line, along the back. They have broad heads, strongly keeled scales and the tail ends with a prominent rattle. The rattle is composed of loosely articulated segments of keratin that make a buzzing sound when shook and a new segment is added to the rattle each time a snake sheds its skin. The rattle is used as a warning to potential predators, if the warning is not headed a snake may use it's venomous bite.

Taxonomy

There are no subspecies of the eastern diamondback rattlesnake.

Distribution

Eastern diamondback rattlesnakes are restricted to the Coastal Plain of the southeastern United States. They historically ranged from extreme eastern Louisiana to southeastern North Carolina and south through all of Florida. Although they can still be locally common these rattlesnakes are experiencing significant population declines throughout their range. Anthropogenic factors such as habitat loss, fragmentation and alteration, and wanton killings are cited as the primary causes of the declines. Currently they are now nearly extirpated from Louisiana, considered endangered in North Carolina and rare in Mississippi, Alabama and South Carolina.

Habitat

The presettlement habitat of eastern diamondback rattlesnakes was likely fire maintained, open canopy, pine habitats, such as longleaf pine/wiregrass uplands and sandhills, pine flatwoods, and pine-oak scrub. Theses habitats have declined significantly due to the spread of agriculture, urbanization, and the removal of fire from the landscape. Eastern diamondback rattlesnakes can also be found in swamp forests, xeric hammocks, temperate hardwood forests and coastal dune habitats as well as agricultural sites, open woodlots and abandoned homesites.

Eastern diamondback rattlesnakes are often found in association with gopher tortoises (Gopherus polyphemus), and their burrows are an important refuge for diamondbacks, especially in the northern parts of their range. Diamondbacks will use these burrows, and other shelters, such as armadillo (Dasypus novemcinctus) burrows, stump holes and the root systems of windfallen trees as a refuge from extreme temperatures, predators and as parturition (birthing) sites.

Movement and Home Range

Home range size in eastern diamondback rattlesnakes can vary greatly between snakes and throughout their range. Home range size may also vary from year to year. Males often have larger home ranges, up to 240 ha (593.1 acres), than females, up to 80 ha (197.7 acres), likely because of their search for mates. Home range sizes are usually much smaller than this, and they may use as little as 4 ha (9.884 acres) in fragmented habitats or on barrier islands.

Eastern diamondback rattlesnakes are most active from April through October. During this time they are almost always on the surface, with the exception of gravid females, which often seek shelter. Movements to foraging sites or in search of mates are primarily diurnal and a peak of activity occurs during the mating season (late August through October). During the colder months, eastern diamondbacks will seek underground shelters such as gopher tortoise burrows, armadillo burrows or stump holes, but will emerge during periods of warmer weather to bask. Eastern diamondbacks may return to suitable overwintering shelters in successive years. In the southern parts of their range, eastern diamondbacks may not seek overwintering shelters due to the warmer climate.

Diet

Eastern diamondback rattlesnakes are ambush predators, using their cryptic coloration to remain concealed. They often coil next to locations that are frequented by prey, such as logs, roots, or rodent trails, and may wait at a suitable location for up to a week. Prey is envenomated with a quick strike and then released. The snake will then track the prey to where it died and ingest it, usually head first. Eastern diamondbacks typically only feed during the warmer months but winter feeding has been recorded. Individuals that feed during the winter are likely in poor body condition, such as post partum females.

Eastern diamondback rattlesnakes feed on a wide variety of endothermic (warm-blooded) prey, although their diet consists mainly of small mammals such as rabbits (Sylvilagus spp.), rats (Sigmodon hispidus, Neotoma floridana), squirrels (Sciurus) and mice (Peromyscus). They also occasionally feed on birds (towhee, eastern meadowlark, bobwhite, king rail, brown thrasher and young turkey have been documented).

Reproduction

Courtship in eastern diamondback rattlesnakes typically takes place from August through September, but may occur as late as December in the southern parts of their range. During this time, males may make large movements in search of a mate. If two males are attempting to mate the same female, they may engage in a ritualized combat, in which they intertwine their bodies and attempt to pin the other to the ground, with the winner gaining breeding rights. Snakes will not attempt to bite each other during combat.

After mating, the female stores the sperm through the winter, and the ova are fertilized the following spring. Gravid females will retreat to a shelter, such as a gopher tortoise burrow or stump hole, during gestation and give birth between late August and early October. Young are born live and litter sizes range from 4-29, with an average of around 14. The female will remain with the newborns until their first shed (7-10 days). Maturity is reached in both sexes at three years, and females only reproduce every two to four years.

Literature Cited

Means, D. B. 2008. Eastern diamondback rattlesnake. In: Amphibians and Reptiles of Georgia. J. B. Jensen, C. D. Camp, W. Gibbons, and M. J. Elliott (eds.). University of Georgia Press, Athens, Georgia.

Martin, W. H., and D. B. Means. 2000. Distribution and habitat relationships of the eastern diamondback rattlesnake (Crotalus adamanteus). Herpetological Natural History 7:9-34.

Timmerman, W. W., and W. H. Martin. 2003. Conservation Guide to the Eastern Diamondback Rattlesnake. Herpetological Circular No. 32:53.

Waldron, J. L., S. H. Bennett, S. M. Welch, M. E. Dorcas, J. D. Lanham, and W. Kalinowsky. 2006. Habitat specificity and home-range size as attributes of species vulnerability to extinction: a case study using sympatric rattlesnakes. Animal Conservation. 9:414-420.

Waldron, J. L., S. M. Welch, and S. H. Bennett. 2008. Vegetation structure and the habitat specificity of a declining North American reptile: A remnant of former landscapes. Biological Conservation. 141:2477-2482.

The Eastern Diamondback
Rattlesnake Conservation Program

Photographs of Eastern Diamondback Rattlesnakes

The Orianne Society has initiated our Eastern Diamondback Rattlesnake Conservation Program (EDBCP) as a program within the Indigo Snake Initiative, to promote the conservation of Eastern Diamondback Rattlesnakes throughout their range.

Unfortunately, much like the Eastern Indigo Snake, the Eastern Diamondback has suffered from the loss, fragmentation, and degradation of native habitats in which it lives. However, like most venomous snakes, the Eastern Diamondback faces additional threats in the form of intense human persecution through rattlesnake roundups, malicious killings, and road mortality. Eastern Diamondback Rattlesnakes, the largest native venomous snakes in North America, have apparently declined in parts of their range where they are subject to intense persecution and habitat loss, and degradation has likely contributed to additional declines.

Eastern Diamondbacks do not receive special protection in most of their range. Eastern Diamondback Rattlesnakes are an integral part of the longleaf pine ecosystem, using Gopher Tortoise burrows for overwinter refugia, preying on a variety of small mammals, and even serving as prey for the Eastern Indigo Snake.

The Eastern Diamondback Rattlesnake’s close association with the longleaf pine ecosystem provides an excellent opportunity to use our on-the-ground conservation efforts for Eastern Indigo Snakes to benefit Eastern Diamondback Rattlesnakes. Its large size (up to eight feet in length), potent venom, and striking pattern make the Eastern Diamondback Rattlesnake a high profile snake within the Coastal Plain.

The mission of the EDBCP is to promote Eastern Diamonback Rattlesnake conservation by using scientific research and monitoring to answer specific questions needed to better conserve and manage Eastern Diamondback Rattlesnakes, and to work with a diverse group of state, federal, and non-governmental organizations (NGO), and private individuals to develop management and conservation strategies for Eastern Diamondback Rattlesnakes. This multi-level and partner-driven approach allows our efforts to have a broader and stronger impact on Eastern Diamondback Rattlesnake conservation.



Protecting the Eastern Diamondback Rattlesnake




Eastern Diamondback Conservation Action Planning Team

The Orianne Society has currently held two Eastern Diamondback Conservation Action Planning Team meetings, one in 2011 at the Southeast Partners for Amphibian and Reptile Conservation (SEPARC) and a second at the Orianne Indigo Snake Preserve in 2012. During these meetings, the Planning Team assessed the current, range-wide status of Eastern Diamondback Rattlesnakes, identified measures that are necessary to ensure their survival, and begun identifying future research and conservation needs. The team is looking forward to reconvening in 2013 to begin assembling the specific portions of the Conservation Action Plan into an comprehensible document that is easily accessible to managers. Stay tuned for updates on this important document! The Orianne Society plans to continue working with local and regional managers to help implement the conservation guidelines in this document to ensure the range-wide persistence of Eastern Diamondback Rattlesnakes.




Georgia Coastal Barrier Islands

The Orianne Society, in conjunction with the University of Georgia, is conducting a research project to determine the effects of coastal development on Eastern Diamondback Rattlesnakes on Georgia's coastal barrier islands. Some  of these barrier islands support healthy populations of Eastern Diamondback Rattlesnakes, yet Georgia's coast is facing increased development and habitat fragmentation. It is important to understand how fragmentation of coastal habitat impacts Eastern Diamondback Rattlesnake populations so that this information can help guide future development in a way that reduces its impact on rattlesnake populations.  This research project focuses on determining how habitat loss and fragmentation has influenced the distribution and abundance of Eastern Diamondback Rattlesnakes on Georgia's barrier islands and includes surveying for Eastern Diamondback Rattlesnakes at multiple sites across several islands and relating rattlesnake occupancy (i.e., presence) to multiple measures of habitat loss and fragmentation. We have completed one season of field work and presented a poster on this project at the Biology of the Rattlesnakes Symposium in Tucson, Arizona.




Altamaha River Drainage

Eastern Diamondback Rattlesnakes are currently found throughout the Altamaha River Drainage in southern Georgia, including the Orianne Indigo Snake Preserve. We are currently monitoring Eastern Diamondback Rattlesnake occupancy (i.e., presence) throughout the Altamaha River Drainage. Because Eastern Diamondback Rattlesnakes utilize Gopher Tortoise burrows as overwintering sites and remain surface active to some degree, we are able to use our Eastern Indigo Snake occupancy surveys to monitor Eastern Diamondback Rattlesnake occupancy. We are also conducting fine scale monitoring through mark-recapture of Eastern Diamondback Rattlesnakes on the Orianne Indigo Snake Preserve to monitor rattlesnake population size, growth, and health. These monitoring programs will allow us to track the status of Eastern Diamondback Rattlesnakes in the Lower Altamaha River Drainage and ensure that this region will continue to remain a stronghold for this species. To date, we have conducted two years of occupancy monitoring and four years of mark-recapture monitoring and look forward to continuing these projects into the future.




Addressing Rattlesnake Roundups

The U.S. Fish and Wildlife recently announced a 90-day review for listing Eastern Diamondback Rattlesnakes as a threatened species. Regardless of whether the Eastern Diamondback is ultimately listed, The Orianne Society is committed to the conservation of this species.

We conduct education and outreach throughout the southeast to raise awareness about Diamondbacks and other imperiled snake species. We are also working to promote the conversion of "rattlesnake roundups" to conservation events.

In the spring of 2012 The Orianne Society participated in the Claxton Georgia Rattlesnake and Wildlife Festival. Formerly known as the Claxton Rattlesnake Roundup, this event proved that these roundups can successfully transition to conservation events and still be an economic asset to their community.

Utilizing the facilities at the Orianne Center for Indigo Conservation, we plan to house and provide animals for the Claxton Wildlife Festival to ensure its continued success. Wherever possible, we are ready to supply our expertise in snake conservation, husbandry, and education to other such events that require logistical support.