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Southern Copperhead

Agkistrodon contortrix

What do they look like?

Agkistrodon contortrix individuals are known for their reddish-brown bodies with a crossband pattern consisting of tan, copper, and rich brown colors that extend throughout the body. Adult copperheads average 76 cm in length and are often described as heavy-bodied snakes. Males tend to have longer bodies than females. The head is very distinct from the rest of the body and has a solid, rich brown color. Temperature-sensitive pit organs are present be between the eye and the nostril. Although copperheads are venomous, their venom is somewhat mild compared to other snake species and is usually not fatal to healthy human adults.

Juveniles have very similar crossband patterns as adults but are much grayer in color. Besides their color differences, juveniles also have a yellow-tinted tail tip until they reach the age of 3 to 4 years. The tinted tail is also found in other Agkistrodon species (Cottonmouth, Agkistrodon piscivorus, for example) and appears to be used to lure small prey within striking distance by mimicking caterpillar movements. Copperheads have a pair of fangs that inject venom when they bite, and even newborn copperheads can give a venomous bite. (Andrews and Wilson, 2014; Ernst and Ernst, 2011; Krysko and King, 2014)

  • Sexual Dimorphism
  • male larger
  • Range length
    135 (high) cm
    53.15 (high) in
  • Average length
    76 cm
    29.92 in

Where do they live?

Copperheads (Agkistrodon contortrix) are found in 28 states throughout the central and eastern United States. Their geographic range extends from southern New England to the eastern parts of Kansas and Nebraska, and then south to eastern Texas to the Florida panhandle. They are also found in localized parts of western Texas and northern Coahuila and Chihuahua, Mexico. (Conant and Collins, 1998)

What kind of habitat do they need?

Copperheads live in different habitats in different parts of their range. In the northeast and the Appalachian Mountains, they are usually found in deciduous forests and open woodlands with rock outcrops and hills. They are often found in places where there are fallen trees and branches. On the southern coastal plain, they can be found in low, wet woodlands including the edges of swamps. Further west, they are associated with areas along streams and rivers with mixed woodlands They are also found in man-made environments including construction areas, sawdust piles, and suburban neighborhoods.

The sites where they spend the winter are often south- or west-facing and include rock crevices, abandoned mines, caves, hollow logs, stumps, and building foundations. Females carrying babies also tend to use such sites and prefer microhabitats with higher temperature profiles. (Carter, 2013; Ernst and Ernst, 2011; Smith, et al., 2009; Szalay, 2014)

How do they grow?

Like other vipers, female copperheads give birth to live young, they don't lay eggs. Newborn copperheads are capable of finding and capturing their own prey at the time of birth, and leave their mother within a few days of birth. Their colors change as they grow, but their body structure does not change. (Van Dyke and Beaupre, 2012)

How do they reproduce?

Males search for mates during the breeding season by detecting pheromones in the air with their tongues. Males have longer tongues than females – a sexual size dimorphism that may aid in the search for a mate. Male to male competition can be fierce and involves various types of combat. Most combat occurs through the lifting of the anterior half of the body and is followed by a series of intertwined lunges and twirls. The male that is able to keep his head lifted and raised the longest is deemed the winner and gets access to the nearby female and courtship ensues.

After the male has earned the mating right to pursue the female, the male must participate in another intertwining battle with the female. Both sexes lift the anterior half of their bodies (similar to the male to male combat stance) and the male rubs his chin across the female's back while flicking his tongue. A receptive female will raise her tail and open her cloaca as an invitation for the male. Receptive females have been known successfully mate with multiple males resulting in multiple paternity of a litter. If a female is not interested, the female will swing her tail and continuously move to avoid copulation. (Schuett and Duvall, 1996; Schuett and Gillingham, 1988; Schuett and Gillingham, 1989; Smith, et al., 2008)

Males search for mates during the breeding season by detecting the scent of females on the ground and in the air. If two males find a female at the same time, they may fight to determine which one gets to court her. Most combat occurs through the lifting of the anterior half of the body and is followed by a series of intertwined lunges and twirls. The male that is able to keep his head lifted and raised the longest is deemed the winner and gets access to the nearby female and courtship ensues.

After the male has earned the mating right to pursue the female, the male must participate in another intertwining battle with the female. Both sexes lift the anterior half of their bodies (similar to the male to male combat stance) and the male rubs his chin across the female's back while flicking his tongue. The female chooses whether or not to mate. Both males and females may mate with more than one partner. (Schuett and Duvall, 1996; Schuett and Gillingham, 1988; Schuett and Gillingham, 1989; Smith, et al., 2008)

Most A. contortrix populations that have been studied have two mating seasons: one from February to May and another from August to October. Research on a northern population at the edge of the geographic range do not show spring breeding.

Copperheads of both sexes reach sexual maturity at 3 to 4 years of age. Once they are mature, females may breed once per year, but it is also common for them to skip one or two years between births. The timing might depend on the food supply: if there is plenty of prey they can breed every year, but if not they may have to skip a year or two. Baby copperheads grow in their mother for about 83 days. There are usually 4 to 8 young, but there can be up to 21. Bigger and older females tend to have larger litters. The size of the young at birth is related to the size of their mother, bigger females give birth to bigger offspring. Newborn copperheads average 20.6 cm in length have an average weight of 10.6 g. (Ernst and Ernst, 2011; Fitch, 1960; Schuett and Gillingham, 1986)

  • How often does reproduction occur?
    1 to 3 years
  • Breeding season
    Copperheads have two breeding seasons: February to May, and August to October
  • Range number of offspring
    1 to 21
  • Average number of offspring
    6
  • Average number of offspring
    6
    AnAge
  • Range gestation period
    83 to 150 days
  • Average gestation period
    110 days
  • Average age at sexual or reproductive maturity (female)
    3.5 years
  • Average age at sexual or reproductive maturity (female)
    Sex: female
    730 days
    AnAge
  • Average age at sexual or reproductive maturity (male)
    3.5 years
  • Average age at sexual or reproductive maturity (male)
    Sex: male
    730 days
    AnAge

Female copperheads produce eggs, but like all viper species and many other snakes, they don't release the eggs from their body until the young in the egg are read to hatch. After the young are released, they stay near their mother for a few days, and but then they disperse and live on their own. Males do not care for the young, and females only protect them for a few days or less. (Ernst and Ernst, 2011; Fitch, 1960; Greene, et al., 2002)

  • Parental Investment
  • pre-fertilization
    • provisioning
  • pre-hatching/birth
    • protecting
      • female
  • pre-independence
    • protecting
      • female

How long do they live?

In captivity, copperheads can live 20 to 29 years. One wild snake is known to have survived 18 years, but studies of the age of copperheads in the wild shows they most of them probably don't live more than 15 years. (Ernst and Ernst, 2011; Fitch, 1960; Vial, et al., 1977)

  • Range lifespan
    Status: wild
    18 (high) years
  • Range lifespan
    Status: captivity
    29 (high) years
  • Typical lifespan
    Status: wild
    15 (high) years
  • Typical lifespan
    Status: captivity
    23 (high) years

How do they behave?

Copperheads are active from March or April to early November in the northern part of their range. During the winter, they have been observed to bask on warm days in December and January. Although copperheads sometimes hibernate alone, it is common for them to hibernate with other copperheads and with other species of snakes, including timber rattlesnakes, eastern racers, and eastern rat snakes). When emerging in the spring, copperheads will tend to bask close to the hibernaculum for several weeks before becoming more active. Hibernacula are often outside the feeding range of the snake during the activity period, necessitating relatively long movements to and from hibernacula on a seasonal basis.

Copperheads are primarily active during daylight hours during the spring and fall. During the summer months, they may hunt during cooler evening hours. However, copperheads carefully select their resting locations during daylight hours so they can use sun and shade to keep their body temperatures between 23 to 31 degrees Celsius. Though they are most often found on the ground, snakes have been observed up to 5 meters up in shrubs and small trees, probably climbing to find the right temperature.

Males move around more than females, especially during the mating season, because they are searching for females. Meanwhile, females carrying eggs move shorter distances than females with no eggs. Females with eggs are often found near their hibernaculum, groups of 4 to 6 individuals. (Carter, 2013; Ernst and Ernst, 2011; Sanders and James, 1981; Schuett, et al., 2002; Smith, et al., 2009)

  • Range territory size
    100 to 440000 m^2

Home Range

Radiotelemetry studies have indicated that home ranges are greatly influenced by habitat availability in likely association with thermoregulatory opportunities. In accordance with the discussion above on movement, males have larger home ranges (6.0 to 44.0 hectares) than females (0.01 to 15.7 hectares), with non-gravid females having larger home ranges than non-gravid females. (Carter, 2013; Fitch, 1960; Smith, et al., 2009)

How do they communicate with each other?

Copperheads rely on olfaction for mate searching, and prey and predator detection. Their forked tongue collects chemical signals that are detected on chemoreceptors on the tongue and in the vomeronasal organ located in the dorsal region of the mouth.

In addition, they also use heat-sensitive facial pits to locate the position of primarily endothermic prey. The pits, located on either side of their face, allow estimation of the direction from which the heat source originates. (Ernst and Ernst, 2011; Zug, 2013)

Copperheads can see, but they also use their sense of smell for to find mates, prey, and detect predators. They also have heat-sensitive pits on their face to locate the position of prey. The pits, are on either side of their face, so they can find prey even in complete darkness. (Ernst and Ernst, 2011; Zug, 2013)

What do they eat?

Copperheads are carnivores. Adults mostly eat rodents while young ones eat many kinds of prey, including salamanders, frogs, lizards, small snakes, and insects. They eat whichever kinds of prey are available and common where they live.

Adults use their camouflage to surprise their prey. They site and wait for prey to come near, and therefore do not travel far while hunting. They sense their prey by scent, sight, and heat, and bite very fast. Bigger copperheads can inject more venom to the prey. The venom causes internal bleeding and destroy cells inside the prey. Laboratory studies have reported that mice injected with copperhead venom are unable to move for 30 to 60 minutes. Large prey require tracking after they have been bit, while smaller prey can be held in the mouth of a copperhead until it dies. Unlike adults, juvenile copperheads sometimes chase after prey. They also have been reported to lure small animals close to them by wiggling their yellow tail, making it look like a worm. (Conant and Collins, 1998; Ernst and Ernst, 2011)

  • Primary Diet
  • carnivore
    • eats terrestrial vertebrates
  • Animal Foods
  • birds
  • mammals
  • amphibians
  • reptiles
  • carrion
  • insects
  • terrestrial non-insect arthropods

What eats them and how do they avoid being eaten?

Copperheads have many predators and are most vulnerable when young. Multiple snake taxa, including kingsnakes, racers, and cottonmouths prey on copperheads. They can also be preyed upon by bullfrogs, alligators, American crows, hawks, owls, opposums, coyotes, and feral cats.

To avoid predation, copperheads stay still and hide under leaves, brush, and cover, including man-made structures. When forced to expose themselves for thermoregulation, copperheads further rely on their markings for camouflage to avoid detection. If threatened, copperheads may vibrate the tip of their tail to mimic a rattlesnake, and will strike when sufficiently threatened. This can usually act as a sufficient deterrent from predation but kingsnakes and opossums are reported to be immune to their venom.

Humans are one of the main predators for A. contortrix. (Ernst and Ernst, 2011; Gloyd and Conant, 1990)

  • These animal colors help protect them
  • mimic
  • cryptic

What roles do they have in the ecosystem?

Copperheads play an intermediate role in food webs. They are both predators of many primary and secondary consumers and also prey to a range of secondary and tertiary consumers. Because they tend to prey on whichever species of rodent is most common in their habitat, they may affect the diversity of rodents where they live. (Ernst and Ernst, 2011)

Do they cause problems?

Because they live around people more than most other venomous snakes, copperheads produce the largest number of venomous snake bites per year due in the United States. Fortunately, their venom is one of the least toxic of all North American snake species. It is estimated that one third of bites produce effects requiring clinical treatment with about 10% considered serious. Bites very rarely lead to death in humans, children and older adults are considered most vulnerable. (Ernst and Ernst, 2011)

  • Ways that these animals might be a problem for humans
  • injures humans

How do they interact with us?

There are many different types of molecules in copperhead venom. They are being studied for use as drugs and medicines. One of them, called contortrostatin, may help treat cancer. (Ernst and Ernst, 2011)

Are they endangered?

Copperheads are listed as a species of Least Concern (LC) on the IUCN Red List of Threatened Species as of 2007. Their placement of “Least Concern” can be due to their large population size and/or their large geographic distribution. However, certain areas of the United States are experiencing declines in populations and they are considered endangered in Iowa and Massachusetts. Threats that have been identified include habitat destruction, invasive plants, insecticide application, and road mortality. (Carter, 2013; Ernst and Ernst, 2011; Frost, et al., 2007)

Contributors

Anna Hartsuff (author), Indiana University-Purdue University Fort Wayne, Mark Jordan (editor), Indiana University-Purdue University Fort Wayne.

References

Amphibian and Reptile Diversity Research Center, 2014. "Copperheads" (On-line). Snakes of Dallas Fort Worth and Nearby Vicinities. Accessed July 05, 2015 at http://www.uta.edu/biology/herpetology/copperheads.htm.

Andrews, K., J. Wilson. 2014. "Copperhead (Agkistrodon contortrix) - Venomous" (On-line). Savannah River Ecology Laboratory Herpetology Program. Accessed April 01, 2014 at http://srelherp.uga.edu/snakes/agkcon.htm.

Booth, W., C. Smith, P. Eskridge, K. Shannon, J. Mendelson III, G. Schuett. 2012. Facultative parthenogenesis discovered in wild vertebrates. Biology Letters, 8: 983-985.

Booth, W., G. Schuett. 2011. Molecular genetic evidence for alternative reproductive strategies in North American pitvipers (Serpentes, Viperidae): long-term sperm storage and facultative parthenogenesis. Biological Journal of the Linnean Society, 104: 934-942.

Carter, E. 2013. M.S. Thesis: Impacts of Invasive Plants on Resource Selection and Thermoregulation by the Northern Copperhead (Agkistrodon contortrix mokasen).. Fort Wayne, IN: Purdue University.

Conant, R., J. Collins. 1998. A Field Guide to Reptiles and Amphibians: Eastern/Central North America. New York: Houghton Mifflin Company.

Douglas, M., M. Douglas, G. Schuett, L. Porras. 2009. Climate change and evolution of the New World pitviper genus Agkistrodon (Viperidae). Journal of Biogeography, 36: 1164-1180.

Ernst, C., E. Ernst. 2011. Venomous Reptiles of the United States, Canada, and Northern Mexico. Baltimore, Maryland: Johns Hopkins University Press.

Fitch, H. 1960. Autecology of the copperhead. University of Kansas Museum of Natural History Publications, 13: 85-288.

Frost, D., G. Hammerson, G. Santos-Barrera. 2007. "Agkistrodon contortrix" (On-line). The IUCN Red List of Threatened Species. Version 2014. Accessed July 16, 2014 at http://www.iucnredlist.org/details/64297/0.

Gloyd, H., R. Conant. 1990. Snakes of the Agkistrodon complex: a monographic review. Society of the Study of Amphibians and Reptiles, Contributions to Herpetology, 6/1: 1-614.

Greenbaum, E. 2004. The influence of prey-scent stimuli on predatory behavior of the North American copperhead Agkistrodon contortrix (Serpentes: Viperidae). Behavioral Ecology, 15/2: 345-350.

Greene, H., P. May, D. Hardy, Sr., J. Sciturro, T. Farrell. 2002. Parental behavior by vipers. Pp. 179-206 in G Schuett, M Hoggren, M Douglas, H Greene, eds. Biology of the Vipers. Eagle Mountain, UT: Eagle Mountain Publishing. Accessed June 24, 2014 at http://www.eaglemountainpublishing.com/.

Jordan, M. 2015. An independent observation of facultative parthenogenesis in the Copperhead (Agkistrodon contortrix). Journal of Herpetology, 49/1: 118-121. Accessed June 23, 2014 at http://journalofherpetology.org/doi/abs/10.1670/14-017.

Krysko, K., F. King. 2014. "Yellow tails of juvenile cottonmouths and copperheads" (On-line). Online Guide to the Snakes of Florida. Accessed July 05, 2015 at http://www.flmnh.ufl.edu/herpetology/fl-guide/compare6.htm.

Mengak, M. 2003. "Copperhead (Agkistrodon contortrix)" (On-line). Accessed April 01, 2014 at http://warnell.forestry.uga.edu/SERVICE/LIBRARY/index.php3?docID=418&docHistory%5B%5D=13.

Sanders, S., J. James. 1981. Thermal ecology of the copperhead (Agkistrodon contortrix). Herpetologica, 37/4: 264-270.

Schuett, G., P. Fernandez, W. Gergits, N. Casna, D. Chiszar, H. Smith, J. Mitton, S. Mackessy, R. Odum, M. Demlong. 1997. Production of offspring in the absence of males: evidence for facultative parthenogenesis in bisexual snakes. Herpetological Natural History, 5: 1-10.

Schuett, G., J. Gillingham. 1988. Courtship and mating of the copperhead, Agkistrodon contortrix. Copeia, 1988: 374-381.

Schuett, G., M. Hoggren, E. Douglas, H. Greene. 2002. Biology of the Vipers. Eagle Mtn., Utah: Eagle Mountain Publishing.

Schuett, G., D. Duvall. 1996. Head lifting by female copperheads, Agkistrodon contortrix, during courtship: Potential mate choice. Animal Behaviour, 51/2: 367.

Schuett, G., J. Gillingham. 1989. Male-male agonistic behaviour of the copperhead, Agkistrodon contortrix. Amphibia-Reptilia, 10/3: 243-266.

Schuett, G., J. Gillingham. 1986. Sperm storage and multiple paternity in the copperhead, Agkistrodon contortrix. Copeia, 1986/3: 807-811.

Smith, C., K. Schwenk, R. Earley, G. Schuett. 2008. Sexual size dimorphism of the tongue in a North American pitviper. Journal of Zoology, 274/4: 367-374.

Smith, C., G. Schuett, R. Earley, K. Schwenk. 2009. The spatial and reproductive ecology of the copperhead (Agkistrodon contortrix) at the northeastern extreme of its range. Herpetological Monographs, 23/1: 45-73.

Szalay, J. 2014. "Copperhead snake: facts and pictures" (On-line). LiveScience. Accessed April 01, 2014 at http://www.livescience.com/43641-copperhead-snake.html.

Van Dyke, J., S. Beaupre. 2012. Stable isotope tracer reveals that viviparous snakes transport amino acids to offspring during gestation. The Journal of Experimental Biology, 215: 760-765.

Vial, J., T. Berger, W. McWilliams, Jr.. 1977. Quantitative demography of copperheads Agkistrodon contortrix (Serpentes: Viperidae). Researches on Population Ecology, 18: 223-234.

Zug, G. 2013. "Chemoreception" (On-line). Accessed May 24, 2014 at http://www.britannica.com/EBchecked/topic/498684/reptile/38478/Chemoreception.

 
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Hartsuff, A. 2015. "Agkistrodon contortrix" (On-line), Animal Diversity Web. Accessed November 15, 2018 at http://www.biokids.umich.edu/accounts/Agkistrodon_contortrix/

BioKIDS is sponsored in part by the Interagency Education Research Initiative. It is a partnership of the University of Michigan School of Education, University of Michigan Museum of Zoology, and the Detroit Public Schools. This material is based upon work supported by the National Science Foundation under Grant DRL-0628151.
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