One of the largest of the snakes in North America, and the largest of the 32 known rattlesnake species, the eastern diamondback (Crotalus adamanteus) is endemic to the Southeastern United States. It inhabits coastal lowlands up to 500 meters (1500 feet) in elevation. The eastern diamondback currently occurs from southeast North Carolina to eastern Louisiana and throughout Florida. Historically its range was considerably larger and less patchy.
Eastern diamondbacks can reach lengths greater than 2.3 m (7 feet), though they usually range between 1-2 m (3-6 feet) long. A characteristic pattern of large, crisp, dark brown and cream-colored diamonds runs down its back. It has yellow stripes on either side of its head, running diagonally across the eye, and black and white bands adjacent to its rattle at the end of its tail.
Like most rattlesnakes, eastern diamondbacks live exclusively on the ground and rarely climb into vegetation. They inhabit upland forests, fields, scrub and hammocks, and less often swamps and marshes. Excellent swimmers, they have colonized the Keys and Atlantic and Gulf coast barrier islands. Eastern diamondbacks come out in mornings and afternoons, when they can frequently be found basking in the sun, and they hunt by night. These snakes sometimes actively forage but more often lie in ambush for small mammals including rabbits, rodents, squirrels and birds. They strike their prey with venomous fangs then wait until it is subdued before swallowing it, usually headfirst. In winter eastern diamondbacks hibernate in underground shelters, often using gopher tortoise or armadillo burrows. The same holes are reused multiple years.
Eastern diamondbacks mate in the late summer and fall, and females hold fertilized eggs internally while they develop, 6-7 months. The mother then gives birth to live-born young in gopher tortoise burrows or hollow logs. The brood usually numbers 16-21 babies. Newborn snakes are about 38 cm (15 inches) long. Just hours after birth they are self-sufficient. The young look very similar to adults, but instead of a rattle they have a “button” at the tip of their tail. This button is the first segment from which their rattle will develop. With each shedding of its skin, an eastern diamondback adds a subsequent segment to their rattle.
After birth, diamondback littermates aggregate together, piling on top of each other until their first molt, which occurs about 10 days later. This aggregation behavior may help newborns reduce water loss through their neonatal skin. Aggregation may also allow siblings to learn conspecific scents, which helps them follow trails to den localities later in life. Some evidence suggests that the mother stays with, or at least near, her litter for this time. After their first molt, young diamondbacks become independent.
Eastern diamondbacks can live more than 20 years. Young snakes, however, experience high mortality. Predators include birds of prey, owls, and other snakes such as the indigo snake (Drymarchon corais) and the eastern kingsnake (Lampropeltis getulus).
Humans are clearly the most significant enemy of the diamondback. These snakes are highly vulnerable to urban/suburban development, agriculture, tree farming and fire suppression, activities that have destroyed or altered the habitat and shelters upon which they are dependent. A history of hunting eastern diamondbacks for their skins and general persecution (e.g. “rattlesnake roundups” which include gassing of gopher tortoise holes) along with little legal protection has also decreased diamondback numbers considerably. Late maturity, low reproduction rate, and relative large ranges exacerbate their vulnerability to human activities.
Crotalus adamanteus is not usually an aggressive species, and defensively shakes its rattle tail to warn aggressors before it strikes. However, this snake is powerful and if provoked can deliver an extremely painful bite, potentially fatal to humans. Diamondbacks have long fangs that hold a large yield of venom. The venom includes the hemorrhagic protein crotolase, hemotoxins that cause tissue damage, and proteins that interrupts neurotransmission. Several effective antivenoms are available, including CroFab and Antivenin Crotalidae Polyvalent (ACP).
Eastern Diamondbacks are not listed as endangered, but their range and numbers have decreased sharply since the 1960s. This snake is rare or almost extirpated the edges of its range (especially North Carolina and Louisiana), although still locally common in suitable habitat in some areas of Georgia and South Carolina. Florida holds its largest population.
(Butler et al. 1995; Hammerson 2007; Hoss et al. 2010; National Geographic 1996-2016; Wikipedia 2016)
- Butler, J.A., Hull, T.W. and Franz, R., 1995. Neonate aggregations and maternal attendance of young in the eastern diamondback rattlesnake, Crotalus adamanteus. Copeia, 1995(1), pp.196-198.
- Hammerson, G.A. 2007. Crotalus adamanteus. The IUCN Red List of Threatened Species 2007: e.T64308A12762249. Retrieved February 24, 2016 from http://www.iucnredlist.org/details/64308/0.
- Hoss, S.K., Guyer, C., Smith, L.L. and Schuett, G.W., 2010. Multiscale influences of landscape composition and configuration on the spatial ecology of eastern diamond-backed rattlesnakes (Crotalus adamanteus). Journal of Herpetology, 44(1), pp.110-123.
- National Geographic Animals, 1996-2016. Eastern Diamondback rattlesnake. Retrieved February 16, 2016 from http://animals.nationalgeographic.com/animals/reptiles/eastern-diamondback-rattlesnake/
- Wikipedia, The Free Encyclopedia, 19 February 2016. Eastern Diamondback rattlesnake. Retrieved February 24, 2016 from https://en.wikipedia.org/w/index.php?title=Eastern_diamondback_rattlesnake&oldid=705693572.
Types: None designated.
Type-locality: Not specifically stated in original description. Proposed by Schmidt, Check List N. Am. Amph. Rept., 6th ed., 280pp. (McDiarmid et al., 1999).
Eastern diamondback rattlesnake
Global Range: (200,000-2,500,000 square km (about 80,000-1,000,000 square miles)) The range encompasses the Coastal Plain of the southeastern United States from North Carolina to south Florida, and west to Mississippi and the Florida parishes of Louisiana, at elevations extending from near sea level to around 500 meters (Mount 1975, Dundee and Rossman 1989, Palmer and Braswell 1995, Ernst and Ernst 2003, Campbell and Lamar 2004). The major stronghold today is the northern Florida peninsula, eastern and southern Florida panhandle, and southwestern Georgia (Timmerman and Martin 2003).
North Carolina: restricted to the Lower Coastal Plain south of the Neuse River; formerly occurred in the middle Coastal Plain but apparently never in the North Carolina Fall Line sandhills; not known on North Carolina barrier islands. South Carolina: patchily distributed in the lower and middle Coastal Plain; common in the coastal marsh-sea island area, occurring on Edisto and three smaller barrier islands. Georgia: restricted to the Coastal Plain, occurring on the Fall Line sandhills below Columbus (Fort Benning) and thriving on Georgia's sea islands. Florida: throughout the state, including many of the Florida Keys and most of Florida's east and west coast barrier islands. Alabama: does not range to the Fall Line but occurs in the lower Coastal Plain where longleaf pine and wiregrass dominated the uplands originally; has been recorded from Dauphin Island. Mississippi: occurs today principally in the counties of the southeastern portion of the state, east and northeast of the eastern tip of Louisiana; historically may have ranged to the limits of the longleaf pine forest, but today the range has contracted and is confined mainly to the longleaf pine hills and pine flats regions; there are no records from Mississippi barrier islands. Louisiana: nearly extirpated; was confined to the easternmost three of the seven Florida parishes, and never was reported from Louisiana barrier islands (Means, unpublished manuscript).
The Eastern Diamondback lives in the coastal lowlands, ranging from southeast North Carolina to eastern Louisiana, and throughout Florida, including the Florida Keys. (Conant and Collins 1998)
Biogeographic Regions: nearctic (Native )
endemic to a single nation
Regularity: Regularly occurring
Type of Residency: Year-round
Distribution: USA (SE North Carolina, E/S South Carolina, S Mississippi, S Alabama, S Georgia, Florida, SE Louisiana)
Southeastern USA: along the Gulf Coast from southeastern Louisiana and southern Mississippi eastward through peninsular Florida, including the Florida Keys, northward along the coastal plain to southeastern North Carolina (McDiarmid, et al. 1999)
The Eastern diamondback is one of the largest North American snakes, with a record length of 8 feet. However, they are usually 33 to 72 inches in length. The snake has a large head and a bulky body. It has a row of large dark diamonds with brown centers and cream borders down its back. The ground color of the body ranges from olive, to brown, to almost black. The tail is usually a different shade, brownish or gray, and banded with dark rings. At the end of the tail is a well-developed rattle. The head has a light bordered dark stripe running diagonally through the eye. The pupil is vertical (catlike). There is a large pit between the nostril and eye. The young are similar to the adults in color pattern. The tip of the tail of a newborn diamondback ends in a button, which is the first segment of the future rattle. Male and female rattlesnakes look alike. (Conant and Collins 1998, Ashton and Ashton 1985)
Length: 244 cm
This species differs from other rattlesnakes by the following characteristics: crisp dorsal thin yellow diamonds enclosing black pigment centered with brown; densely black face with two thin oblique yellow lines on either side of the black eye (the iris and sclera are not set off from the pupil); olive-brown tail never with bold black and white "coon tail" bands.
The Eastern Diamondback resides in the palmetto flatwoods and dry pinelands of the South. It generally avoids marshes and swamps, but on occasion will live near the borders of wetlands. Occasionally it may venture into salt water, swimming to the outlying Keys off the Florida coast. (Conant and Collins 1998, Ashton and Ashton 1985)
Terrestrial Biomes: chaparral ; forest
Habitat and Ecology
Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.
Locally Migrant: Yes. At least some populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).
Locally Migrant: No. No populations of this species make annual migrations of over 200 km.
Apparently does not defend a territory. In longleaf pine sandhills habitat, Timmerman (1989) found that females occupied smaller areas (mean=46.5 ha, N=2) than did males (mean=84.3 ha, N=4). Means (unpublished manuscript) measured home range in clayhills habitat in shortleaf/loblobby pine oldfield successional forest that was annually control burned and found males to occupy home ranges of approximately 240 ha (600 acres) and females about 120 ha (300 acres).
In November, makes short movements to one or more holes in the ground used for overwintering (Means, unpublished manuscript); the same holes are utilized in subsequent years. After spring emergence, moves various distances (100-500 m) to find sites with food. Individuals may move as much as a mile (1.6 km) between hunting locations in just one day, but most movements are much shorter (Timmerman and Martin 2003).
The Eastern diamondback feeds primarily on small mammals, from mice to rabbits. It will also eat birds. Young diamondbacks feed primarily on rats and mice, while adults prefer larger prey like rabbits and squirrels. The snakes lie waiting for prey beside logs or near the roots of fallen trees. Diamondbacks locate their prey by odor, as well as by sensing the infrared waves (heat) given off by their warm-blooded prey. Once found, the prey is bitten. The prey is released after the strike, and is then allowed to crawl away and die. The snake will pursue the prey, eating it once it is dead. (Ashton and Ashton 1985, King 1996)
Comments: Prey is principally rodents and lagomorphs, including the eastern cottontail (SYLVILAGUS FLORIDANUS), marsh rabbit (SYLVILAGUS PALUSTRIS), cotton rat (SIGMODON HISPIDUS), cotton mouse (PEROMYSCUS FLORIDANUS), grey squirrel (SCIURUS CAROLINENSIS), fox squirrel (SCIURUS NIGER), and other rodents. Very few birds (bobwhite quail, rufous-sided towhee, king rail, brown thrasher) and no ectothermic vertebrates have been recorded as prey (Means, unpublished manuscript). Employs sit-and-wait ambush behavior; trails envenomated prey very accurately after a refractory period of 2.5 to 39 minutes (Brock 1980); ingests the prey whole, usually head first.
Number of Occurrences
Note: For many non-migratory species, occurrences are roughly equivalent to populations.
Estimated Number of Occurrences: 81 - 300
Comments: This species is represented by a large number of occurrences (subpopulations). On a range-wide scale, Campbell and Lamar (2004) mapped roughly 175 collection sites; however, relatively few of these represent extant populations with good viability.
100,000 - 1,000,000 individuals
Comments: Adult population size is unknown but presumably exceeds 100,000 (several thousand are killed annually for the skin trade). This snake is rare in North Carolina (Palmer and Braswell 1995) and Louisiana (Dundee and Rossman 1989). However, it is still locally common in suitable habitat in some areas of Georgia, South Carolina, and Florida (Ernst and Ernst 2003).
Reported density ranges from about 18 individuals/ha in muhlenbergia grass on a barrier spit to one individual per 6 ha in shortleaf/loblolly pine oldfield successional habitat on clayhills (Means, unpublished manuscript). The acreage required to maintain a minimum viable population is not yet known.
The principal predators and enemies are other snakes, including the indigo snake (DRYMARCHON CORAIS COUPERI), which feeds upon diamondbacks, and the eastern kingsnake (LAMPROPELTIS GETULUS), which takes young rattlesnakes occasionally. The red-tailed hawk is a known predator and several other birds of prey are suspected of feeding on medium- and small-sized rattlesnakes. Feral hogs have been reported to kill and feed on small rattlesnakes and white-tailed deer have been reported to stamp rattlesnakes to death (Timmerman 1989; Means, unpublished manuscript). Fire is a known source of mortality, albeit probably not very important (Means, unpublished manuscript). No doubt humans are presently the most serious source of direct mortality (roadkilling, clubbing, shooting, and collecting for sale of skins or for rattlesnake roundup competitions) (Means, unpublished manuscript).
Life History and Behavior
Comments: Most activity occurs from April to October, but these snake commonly make visits to the ground surface on warm days in the winter and sometimes may feed then. Active occurs mainly in early morning, evening, and at night.
Lifespan, longevity, and ageing
Eastern Diamondbacks mate in the late summer and fall. The size of the brood ranges from 6 to 21 young. The gestation period is six to seven months. Young are born live, in retreats such as gopher tortoise burrows or hollow logs. At the time of birth, the baby snakes are 15 inches long. The snakes can live 20 years or more. (Georgia Wildlife Federation 1999)
Mating takes place in August and September. Females store sperm until the following April when ovulation and fertilization take place. Gestation requires about 120 days. Vitellogenesis begins in the ovaries of females in the fall preceeding gravidity and birth (Means, unpublished manuscript). Females give live birth in August and September to an average of about 14 young. Females may remain in the vicinity of the newborn for several days. Males may reach sexual maturity by the time of their second birthday; females at year three (Means, unpublished manuscript). Males and females both probably participate in courtship and mating every August and September after reaching sexual maturity, but females usually reproduce every two or possibly three years after giving birth to their first clutch (Means, unpublished manuscript). In captivity, individuals have lived for more than 22 years (Bowler 1977).
Molecular Biology and Genetics
Statistics of barcoding coverage: Crotalus adamanteus
Public Records: 0
Specimens with Barcodes: 3
Species With Barcodes: 1
Though not endangered, the Eastern Diamondback is clearly in trouble. The snake is rapidly disappearing from many areas in which it formerly occupied. Suburban housing and agricultural development destroys vast areas of habitat for the rattlesnake. Most snakes are killed on sight when found by humans. 'Rattlesnake roundups' held annually in several states of the U.S. further decrease their numbers. Crotalus adamanteus is regulated in North Carolina, a permit is required to
collect it, and in Florida a permit is needed to possess all vcenomous snakes. (King 1996, Georgia Wildlife Federation 1999, Levell 1997)
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: least concern
IUCN Red List Assessment
Red List Category
Red List Criteria
National NatureServe Conservation Status
Rounded National Status Rank: N4 - Apparently Secure
NatureServe Conservation Status
Rounded Global Status Rank: G4 - Apparently Secure
Reasons: Loss of habitat coupled with high mortality have led to severe decline since the 1960s and 1970s. Heavy exploitation for the skin trade, general persecution, and little or no legal protection.
Intrinsic Vulnerability: Moderately vulnerable
Comments: A number of features of the species' life history increase its vulnerability. These include: reliance on subterranean refugia (from fire and extreme temperature), particularly stumpholes (threatened by stump removal for naval stores) and gopher tortoise burrows; late maturity; low recruitment; non-annual reproduction; and large home ranges that frequently are crossed by roads and which hence exacerbate mortality.
Global Short Term Trend: Decline of 10-30%
Comments: Area of occupancy, number of subpopulations, and population size probably are declining throughout the range. The habitat continues to be drastically reduced at the northern extent of the range in North Carolina (Palmer and Braswell 1995). Substantial habitat loss is continuing in Florida (Tennant 1997). The rate of decline is unknown, but it may exceed 10 percent over three generations (probably at least 15-20 years).
Eastern diamondbacks have been able to occupy many of the ruderal habitats that have sprung up in place of the native longleaf forest habitats, but these are also declining in percentage of the landscape (Ware et al. 1993; Means, unpublished manuscript).
Global Long Term Trend: Decline of 30-70%
Comments: Area of occupancy, number of subpopulations, and population size clearly have decllined significantly compared to the historical situation. This species probably ranged throughout the original extent of the longleaf pine forest in the Coastal Plain, but the longleaf pine forest now occupies only a small percentage of its former extent (Ware et al. 1993). Longleaf pine upland habitat has shrunk from 60.6% to less than 1.4% of the landscape since presettlement times (Ware et al. 1993), so that the principal natural habitat of the species has diminished greatly.Many animals endemic in the longleaf pine forest such as the gopher tortoise and this rattlesnake are suffering range contractions because of the loss of the longleaf pine forest upland habitat in which they evolved and to which they are best adapted.
Range contractions are known from Louisiana, Mississippi, and South and North Carolina.This snake is now very rare or virtually extirpated at the northern and western extremes of the range in North Carolina (Palmer and Braswell 1995) and Louisiana (Dundee and Rossman 1989).
Degree of Threat: High
Comments: The original range has been reduced and fragmented by agriculture, forestry practices, urbanization, and plant succession resulting from fire suppression (Martin and Means 2000).
Current threats to local populations include conversion of native habitat to planted slash or loblolly pine silvicultural plantations, agricultural fields, and urban and suburban uses. More than anything else, human alteration of native longleaf pine upland ecosystems (including fire suppression) is shrinking and fragmenting the suitable habitat base for this species.
Another direct threat is the collecting of rattlesnakes for the skin trade and for competition for prizes in rattlesnake roundups held annually in Alabama (1) and Georgia (3). While probably not a serious threat in itself, when coupled with habitat loss, this sort of collecting is additive. It utilizes the practice of gassing the burrows of the gopher tortoise in winter (illegal in Florida and Georgia), sometimes killing rattlesnakes outright, and usually impacting the other fauna inhabiting burrows (Speake and Mount 1973). Rattlesnake roundups, themselves, account for only about 2,000 snakes per year. The skin trade is more insidious. Skin dealers have a huge network of pick-up stations where they advertise for people to bring in killed snakes to be frozen until the dealers can make the rounds and pick up the carcasses. Rangewide, this sort of activity probably accounts for at least ten times (20,000) the number of rattlesnake deaths caused by roundups (Means, unpublished manuscript). Berish (1998) provided further information on the harvest in Florida.
Restoration Potential: The eastern diamondback rattlesnake fares well in adequate habitat. Viable populations are maintained on islands of a few tens to hundreds of acres. Individuals have been observed swimming in the ocean and in estuaries along the coast. Barrier islands and the Florida Keys are populated with the eastern diamondback rattlesnake, so dispersal and founding of populations has been accomplished under natural circumstances. Restoring Crotalus adamanteus to any suitable site should not be a problem.
Preserve Selection and Design Considerations: The most important consideration in the management of the eastern diamondback rattlesnake is that the area managed should be restored and maintained as close to natural to its presettlement condition. For this species this is a mosaic of wetland and upland habitats associated with longleaf pine forest that is control burned on a 1-5 year frequency in the season May-July. Such a landscape should have its native complement of other animals present in viable populations (food species and the gopher tortoise). Other than control burning, no special management actions are required as presently known.
Management Requirements: The presettlement landscape is the best landscape in which to maintain the eastern diamondback rattlesnake. Under natural conditions the uplands of the Coastal Plain landscape burned over from lightning ignitions as frequently as 1-5 years. Since lightning strikes are not sufficient to ignite areas of only several square kilometers, and since weeks-long fires that burned over several counties in area are not presently possible, controlled burning that mimics the natural fire frequency and season of burning is the principal management requirement necessary to maintain the landscape in the condition most suitable for this species. In the absence of fire, hardwoods eventually invade the open longleaf pine upland habitats and cause them to be grossly altered by plant succession. A landscape dominated by southern temperate hardwood forest (Platt and Schwartz 199X ) or Southern Mixed Hardwood Forest (Ware et al. 1993) is not suitable for the eastern diamondback rattlesnake.
See also Timmerman and Martin (2003).
Management Research Needs: More research on minimum viable population and size of the area required to maintain a minimum viable population is needed. Research is needed to determine what role food supply plays in the reproductive health of females, and whether females could reproduce annually or shorten their ages to maturity by access to unlimited food supply. Very little is known about the first two years of life, when individuals are less than 1.0 meters long. This critical stage in the life history has not been examined. It is believed that rattlesnakes are more vulnerable to predation at young sizes (=ages) and that they are more fossorial during these years (Means, unpublished manuscript).
Biological Research Needs: It is necessary that we learn more about the effects of collecting for the skin trade and gassing of gopher tortoise burrows regionally because of possible unregulated impacts on the eastern diamondback.
Relevance to Humans and Ecosystems
This snake is extremely beneficial to man. It preys on rats, mice, rabbits, and other small mammals, many of which are pests to humans. (Ashton and Ashton 1985)
Comments: Venomous, and highly dangerous to humans; defensive if disturbed, but unaggressive if left alone; see Ernst (1992) for information and references pertaining to envenomation of humans.
Stewardship Overview: Basic life history and ecology information is in the process of being worked up for publication by D. B. Means based on an intensive study of the species over an 8-year period, so more explicit information eventually will be available. This species has been declining over its geographic range in several ways. First, the northern perimeter of the range has been shrinking southward. Second, the western and northeastern ends of the distribution are shrinking toward the middle of the range. Third, throughout the range, the habitat and thus the opportunity for a globally panmictic population has been severely fragmented by humans. The best way to arrest this trend is to manage occupied habitat in ways that promote the preservation and/or maintenance of the full complement of native ecosystems originally thought to have occurred naturally on each site. Usually this is longleaf pine forest on the uplands and wetland habitats naturally adjacent to them, all of which were kept in good condition for the eastern diamondback when fires burned through longleaf pine on a natural May-July season on a 1- 5 year interval, and were allowed to burn into adjacent habitats as far as conditions in those habitats would permit. Killing of eastern diamondbacks should not be permitted nor harvest for commercial purposes from managed lands. Until biologists know differently through further research, it appears that the eastern diamondback rattlesnake will hold its own on large tracts (>2,000 acres) with no specific managment targeted strictly for the species. In other words, if the gradient of natural habitats is intact the species should fare well.
Species Impact: The most significant impacts of the eastern diamondback rattlesnake on other animals is as a predator on rodents and rabbits. A very small number of eastern diamondback snakebites impact human beings every year (less than about 10), and many of these are delivered to people deliberately handling the animals (snake fanciers, roundup yahoos, researchers).
Crotalus adamanteus is a venomous pit viper found in the southeastern United States. It is the heaviest (though not longest) venomous snake in the Americas and the largest rattlesnake. It featured prominently in the American Revolution, specifically as the symbol of what many consider to be the first flag of the United States of America, the Gadsden flag. No subspecies are currently recognized.
This is the largest rattlesnake species and is the heaviest known type of venomous snake, measuring 7.8 ft (2.4 m) in length and weighing 15.4 kg (34 lb), which was shot in 1946. However, other venomous snakes may rival this species in weight, the much longer but more slender king cobra is probably greater in average body mass if not maximum weight and the shorter but even bulkier gaboon viper could (but is not verified to) exceed the rattlesnake in both mean adult body mass and possibly even maximum body mass. Maximum reported lengths for eastern diamondback rattlesnakes are 8 ft (2.4 m) and 8.25 ft (2.5 m). However, the stated maximum sizes have been called into question due to a lack of voucher specimens.
Specimens over 7 ft (2.1 m) are rare, but well documented. Klauber (1998) included a letter he received from E. Ross Allen in 1953, in which Allen explains how for years he offered a reward of $100, and later $200, for an 8 ft (2.4 m) specimen, dead or alive. The reward was never claimed. He did receive a number of 7 ft (2.1 m) range specimens and some 8 ft (2.4 m) skins, but said such skins can be taken from specimens as short as 6 ft (1.8 m). A 7.3 ft (2.2 m) specimen was caught and killed outside a neighborhood in St. Augustine, Florida in September 2009.
The average size is much less: lengths of 3.5 to 5.5 ft (1.1 to 1.7 m), and 2.75 to 6 ft (0.8 to 1.8 m) are given. One study found an average length of 5.6 ft (1.7 m) based on 31 males and 43 females. The average body mass is roughly 2.3 kg (5.1 lb). The average weight of 9 laboratory-kept specimens was 2.55 kg (5.6 lb), with a range of 0.8 to 4.9 kg (1.8 to 10.8 lb). Few specimens can exceed 5.12 kg (11.3 lb), although exceptional specimens can weigh 6.7 kg (15 lb) or more.
The scalation includes 25-31 (usually 29) rows of dorsal scales at midbody, 165-176/170-187 ventral scales in males/females and 27-33/20-26 subcaudal scales in males/females, respectively. On the head, the rostral scale is higher than it is wide and contacts two internasal scales. There are 10-21 scales in the internasal-prefrontal region and 5-11 (usually 7-8) intersupraocular scales. Usually, there are two loreal scales between preoculars and the postnasal. There are 12-17 (usually 14-15) supralabial scales, the first of which is in broad contact with the prenasal, and 15-21 (usually 17-18) sublabial scales.
The color pattern consists of a brownish, brownish-yellow, brownish-gray or olive ground color, overlaid with a series of 24-35 dark brown to black diamonds with slightly lighter centers. Each of these diamond-shaped blotches is outlined with a row of cream or yellowish scales. Posteriorly, the diamond shapes become more like crossbands and are followed by five to 10 bands around the tail. The belly is a yellowish or cream-colored, with diffused, dark mottling along the sides. The head has a dark postocular stripe that extends from behind the eye backwards and downwards to the lip; the back of the stripe touches the angle of the mouth. Anteriorly and posteriorly, the postocular stripe is bordered by distinct white or yellow stripes.
Common names include eastern diamondback rattlesnake, eastern diamond-backed rattlesnake, eastern diamondback, diamond rattlesnake, diamond-back rattlesnake, common rattlesnake, diamond-back, diamond(-patch) rattler, eastern diamond-back (rattlesnake), eastern diamond rattlesnake, Florida diamond-back (rattlesnake), Florida rattlesnake, lozenge-spotted rattlesnake, rattler, rattlesnake, southeastern diamond-backed rattlesnake, southeastern diamond-backed rattler, southern woodland rattler, water rattle, water rattlesnake, and diamondback rattlesnake.
C. adamanteus is found in the southeastern United States from southeastern North Carolina, south along the coastal plain through peninsular Florida to the Florida Keys, and west along the Gulf Coast through southern Alabama and Mississippi to southeastern Louisiana. The original description for the species does not include a type locality, although Schmidt (1953) proposed it be restricted to "Charleston, South Carolina" (USA).
This species is classified as Least Concern on the IUCN Red List (v3.1, 2001). Species are listed as such due to their wide distribution, presumed large population, or because they are unlikely to be declining fast enough to qualify for listing in a more threatened category. The population trend was down when assessed in 2007.
This species is currently under review for being added to the Endangered Species List by the United States Fish and Wildlife Service due to their recent declines, and their current population represents only 3% of their historical population.
This rattlesnake inhabits upland dry pine forest, pine and palmetto flatwoods, sandhills and coastal maritime hammocks, longleaf pine/turkey oak habitats, grass-sedge marshes and swamp forest, cypress swamps, mesic hammocks, sandy mixed woodlands, xeric hammocks, and salt marshes, as well as wet prairies during dry periods. In many areas, they seem to use burrows made by gophers and gopher tortoises during the summer and winter.
These snakes frequently shelter by tunneling in gopher and tortoise burrows, emerging in the early morning or afternoon to bask.
Like most rattlesnakes, this species is terrestrial and not adept at climbing. However, they have on occasion been reported in bushes and trees, apparently in search of prey. Even large specimens have been spotted as high as 10 m above the ground.
They are also known to be excellent swimmers. Specimens have often been spotted crossing stretches of water between barrier islands and the mainland off the Georgia coast, in the Gulf of Mexico and in the Florida Keys, sometimes miles from land.
Individual disposition varies, with some allowing close approach while remaining silent, and others starting to rattle at a distance of 20–30 ft (6–9 m). The rattle is well developed and can be heard from relatively far away. When threatened, they raise the anterior half of their bodies off the ground in an S-shaped coil, and can strike to a distance of at least a third of their body length. Many will stand their ground and may strike repeatedly, but if given the opportunity, they will usually retreat while facing the intruder and moving backwards towards shelter, after which they disappear.
One popular myth is these snakes must rattle before striking. To the contrary, these snakes are quite capable of striking while remaining completely silent.
Hawks, eagles, and other snakes have been known to prey upon young and adolescent specimens.
These snakes forage actively or lie in ambush for small mammals, especially rabbits and rice rats (Oryzomys). Their diets also include birds. Prey is struck and released, after which the snake follows the scent trail left by the dying prey.
Because of their large size, adults have no problem eating prey as large as fully grown cottontail rabbits. As the juveniles are capable of swallowing adult mice, even they do not often resort to eating slimmer prey, such as lizards. In fact, eastern cottontails and marsh rabbits (Sylvilagus) form the bulk of their diets in most parts of Florida. Squirrels, rats, and mice are also eaten, along with birds such as towhees and bobwhite quail. Other prey that have been reported include a king rail, a young wild turkey, and a mother woodpecker along with four of her eggs. They also eat large insects.
Rattlesnakes, including C. adamanteus, are ovoviviparous. Gestation lasts six or seven months and broods average about a dozen young. However, the young only stay with the mother for a few hours before they set off on their own to hunt and find cover, thus mortality rate is very high.
Females give birth to between seven and 21 young at a time, usually between July and early October. Neonates are 12–14 in (30–36 cm) in length and are similar in appearance to the adults, except for having only a small button instead of a rattle on the tip of their tails.
Eastern diamondbacks can live beyond 20 years, but life expectancy in the wild is now typically shorter because of hunting and human expansion.
Adult wild-caught specimens are often difficult to maintain in captivity, but captive-born individuals do quite well and feed readily on killed laboratory rodents. They require a dry and well-ventilated cage with a hide-box, maintained at a temperature of 73–80 °F (23–27 °C) for normal activity.
This species has the reputation of being the most dangerous venomous snake in North America. While not usually aggressive, they are large and powerful. Wright and Wright mentioned a mortality rate of 30%, but other studies show a mortality rate of 10-20%.
In proportion to its length, it has the longest fangs of any rattlesnake species, with calculations leading one to expect an 8-ft specimen would have fangs with a total length of over 1 in (25 mm). For comparison, a 5-ft specimen had fangs measuring 2⁄3-inch (17 mm) in length. It has a very high venom yield, an average of 400–450 mg, with a maximum of 858-1,000 mg. Brown gives an average venom yield of 410 mg (dried venom), along with LD50 values of 1.3-2.4 mg/kg IV, 1.7-3.0 mg/kg IP and 14.5–10 mg/kg SC for toxicity. The estimated human lethal dose is 100–150 mg.
The venom contains a thrombin-like enzyme, "crotalase", capable of clotting fibrinogen, leading to the secondary activation of plasminogen from endothelial cells. Although the venom does not activate platelets, the production of fibrin strands can result in a reduced platelet count, as well as the hemolysis of red blood cells. Even with this defibrination, however, clinically significant bleeding is uncommon. Nevertheless, the venom does exhibit high hemorrhagic activity. It also contains a low-molecular-weight basic peptide that impedes neuromuscular transmission and can in theory lead to cardiac failure. This peptide is similar to crotamine from C. durrisus terrificus, and makes up 2-8% of the protein found in the venom. In general, the venom can be described as highly necrotizing, mildly proteolytic and containing a large phosphodiesterase fraction. It stimulates the release of bradykinin that can result in severe pain, as well as profound, transient hypotension.
Klauber described one case in which the symptoms included instant pain "like two hot hypodermic needles", spontaneous bleeding from the bite site, intense internal pain, bleeding from the mouth, hypotension, a weak pulse, swelling and discoloration of the affected limb, and associated severe pain. The symptoms were further described as strongly hemolytic and hemorrhagic.
CroFab and Wyeth's ACP are effective antivenoms against bites from this species, although massive doses may be needed to manage severe cases of envenomation. Generally, ACP is very effective at countering the defibrination syndrome that is often seen, but may do little for low platelet counts. Wyeth's ACP is no longer being manufactured.
- List of crotaline species and subspecies
- Crotalus by common name
- Crotalus by taxonomic synonyms
- Crotalinae by common name
- Crotalinae by taxonomic synonyms
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|Wikimedia Commons has media related to Crotalus adamanteus.|
|Wikispecies has information related to: Crotalus adamanteus|
- Crotalus adamanteus at the Reptarium.cz Reptile Database. Accessed 12 December 2007.
- Eastern Diamondback Rattlesnake at Yale Herpetology Page. Accessed 2 March 2007.
- Eastern Diamondback Rattlesnake at Biology Dept., Davidson College. Accessed 2 March 2007.
- Images of Crotalus adamanteus at SREL Herpetology. Accessed 2 March 2007.
- Crotalus adamanteus at Munich AntiVenom INdex. Accessed 2 March 2007.