Eastern diamond-backed rattlesnake (Crotalus adamanteus)

Also known as: eastern diamondback rattlesnake
KingdomAnimalia
PhylumChordata
ClassReptilia
OrderSquamata
FamilyViperidae
GenusCrotalus (1)
SizeLength: up to 2.4 m (2)

Classified as Least Concern (LC) on the IUCN Red List (1).

The largest rattlesnake in the world (3), the venomous eastern diamond-backed rattlesnake is named after the distinctive row of 24 to 35 dark brown-black diamonds, bordered by cream or yellow scales, which run along the length of the back (2) (4) (5). The base colour of the snake is usually brown or tan, while the tail is lighter than the body and has dark bands, although it may also be patternless (2) (5). The head is triangular, and has a dark stripe bordered by a lighter streak that runs diagonally across the eye (2) (4) (5). Juvenile eastern diamond-backed rattlesnakes are similar in colouration to the adult. The conspicuous rattle, found at the end of the tail, is made up of hollow, interlocking segments (3) (4) (5). The tip of the tail in newborn rattlesnakes does not yet have a fully formed rattle, instead ending in a ‘button’, which is retained after the first shed (5).

Endemic to the southeast United States (1), the eastern diamond-backed rattlesnake ranges along the coastal plains from North Carolina, throughout Florida and the Florida Keys, and west to southern Mississippi and eastern Louisiana (1) (2) (5). It is also found on several barrier islands (5).

Recorded from a wide range of habitats, but most often associated with upland pines, especially pine flatwoods, longleaf pine and turkey oak, palmetto flatwoods and scrub (2) (4) (5). It is known to colonise offshore coastal islands, which it reaches by either swimming or rafting (using floating vegetation or other materials to travel across open water) (2) (3).

The eastern diamond-backed rattlesnake often takes refuge in the burrows of other animals, particularly those of the gopher tortoise (Gopherus polyphemus), and will also use holes in stumps, hollow or rotting logs, root channels and other underground cavities (1) (2) (3). In Florida, it has increasingly been associated with new developments, as residential areas continue to encroach into the remainder of its suitable habitat (2) (5).

The eastern diamond-backed rattlesnake has a venomous and potentially lethal bite, and can effectively strike prey within a distance equal to around two-thirds of its body length (2) (5). The primary purpose of the venom is to aid in the digestion of prey, and much more venom is used when biting to obtain food than when biting in self-defence (2) (5). The venom contains a digestive enzyme, made up from a complex mixture of proteins, which attacks the nervous system, blood and tissues (3). It is administered to the prey by a pair of long, movable, needle-like fangs which lie flat inside the mouth when not in use (3) (6). The eastern diamond-backed rattlesnake preys primarily on small mammals such as mice, rats and rabbits, as well as some small birds (2) (3) (5) (6). Hunting is done during the day, with the snake sitting coiled and motionless for long periods of time, waiting to ambush prey that comes within striking distance (2) (3). The rattle is used mainly as a defensive warning signal when the snake is threatened, and the characteristic ‘rattling’ noise is made when the tail is moved rapidly, causing the rattle segments to clash against each other. Each time the snake sheds it skin as it grows, a new segment will be added to the rattle, although these often break off as the snake grows older (3).

The main breeding season occurs during the autumn, from early August to September, and is characterised by an increase in activity, with the male eastern diamond-backed rattlesnake travelling long distances in search of a suitable mate (2). Male rattlesnakes may engage in ritualised combat in order to determine social dominance and breeding rights with receptive females. This combat typically involves tongue flicking, raising parts of the body off the ground, facing-off and entwining around an opponent in an attempt to overpower the subordinate to the ground (2). The female eastern diamond-backed rattlesnake gives birth to between 6 and 21 live young (2) (3), which undergo their first shed after around 10 to 12 days, and are born fully equipped with venom, able to catch and kill their own prey (6).

Habitat destruction and fragmentation is the primary threat to the eastern diamond-backed rattlesnake (2) (3). Throughout its range, agricultural development, forestry, urbanisation and an ever-increasing human population have meant that rattlesnake habitat is rapidly declining (1) (2) (3). Demand for its meat and skin in the curio and leather trades is a further threat (1) (4), and populations in Georgia and Alabama are also under threat from organised events, known as rattlesnake round-ups, where the rattlesnakes are systematically hunted and killed (1) (2) (7). In the past this has often been done using inhumane methods, such as gassing the gopher tortoise burrows in which the snakes shelter, although this practice of gassing has now been made illegal in Georgia and Florida (1) (2) (4).

The eastern diamond-backed rattlesnake occurs in several protected areas in the southeast United States, but there are currently no regulations in place to limit the numbers of rattlesnakes that are harvested from the wild (1) (3). Recommendations made by researchers and wildlife agencies include introducing limits and seasonal harvest guidelines for the number of snakes which can be taken by hunters, refocusing rattlesnake round-ups as wildlife festivals, and reclassifying the eastern diamond-backed rattlesnake as a game animal for which a hunting licence is required (1) (3) (7). However, these proposals have yet to be enforced. In 1993, the Gopher Tortoise Council formed the Rattlesnake Conservation Committee (RCC), which has since evolved into the Upland Snake Conservation Initiative. This initiative aims to promote public education and investigate the biology of the eastern diamond-backed rattlesnake to aid in its conservation (2) (3).

To find out more about the eastern diamond-backed rattlesnake see:

Authenticated (01/11/10) by Fred Antonio, Director of the Orianne Center for Indigo Conservation (OCIC).
http://www.projectorianne.org/

  1. IUCN Red List (July, 2010)
    http://www.iucnredlist.org/
  2. Antonio, F. (2003) The Eastern Diamondback Rattlesnake (Crotalus adamanteus) North American Regional Studbook, 2003, Third Edition.Central Florida Zoological Park, Lake Munroe, Florida. Available at:
    http://library.sandiegozoo.org/studbooks/reptiles/easterndiamondbackrattlesnake2003.pdf
  3. Gopher Tortoise Council (July, 2010)
    http://www.gophertortoisecouncil.org/easterndiamondback.php
  4. Florida Natural Areas Inventory (July, 2010)
    http://www.fnai.org/FieldGuide/pdf/Crotalus_adamanteus.pdf
  5. Florida Museum of Natural History (July, 2010)
    http://www.flmnh.ufl.edu/herpetology/fl-guide/Crotalusadamanteus.htm
  6. Florida Fish and Wildlife Conservation Commission (2004) Florida's Venomous Snakes. FWCC, Tallahassee, Florida. Available at:
    http://myfwc.com/docs/WildlifeHabitats/Guide_to_venomous_snakes_in_FL.pdf
  7. Means, B. (2009) Effects of rattlesnake round-ups on the eastern diamondback rattlesnake (Crotalus adamanteus). Herpetological Conservation and Biology, 4(2): 132-141.