Copperhead (Agkistrodon contortrix): Facts, ID and Habitat

Appearance and identification

The copperhead is a thick-bodied snake with a broad, triangular head that is clearly wider than its neck. The head is an unmarked copper, orange-brown or reddish-tan color, often with a faint dark line behind each eye. The background color of the body ranges from pale tan and pinkish to light reddish brown or grayish brown.

Its signature mark is a row of 10 to 18 darker chestnut crossbands. Each band is wide on the sides of the body and pinched narrow over the spine, so from above it looks like an hourglass; seen from the side, many people say each band looks like a chocolate kiss. Some bands are broken at the midline and alternate on each side. The belly is cream to pinkish, with dark smudges along the edges.

Like all pit vipers, the copperhead has a heat-sensing pit on each side of the face, between the eye and the nostril, and its pupils are vertical slits, like a cat’s. The body scales are weakly keeled, meaning each has a faint ridge down the middle, which gives the skin a matte look. These close-up features are useful in photographs, but they are not something to check in the field: identify any snake from at least a couple of meters away.

Young copperheads look like small, slightly grayer versions of the adults, with one striking difference: a bright sulfur-yellow or greenish-yellow tail tip. That tip darkens to brown or black, usually during the first year or so. Read more in what do baby copperheads look like?

Size

Copperheads are medium-sized snakes. Most adults measure 50 to 95 cm (20 to 37 in) in total length, and anything over 1 m (3.3 ft) is exceptional. The longest reliably reported copperheads were about 132 to 135 cm (52 to 53 in) long.

Males grow larger than females. In one widely cited data set, adult males weighed about 100 to 340 g (3.5 to 12 oz), with an average near 200 g (7 oz), while females averaged about 120 g (4 oz).

Habitat and range

The eastern copperhead lives in the eastern and central United States. Its range runs from southern New England and southeastern New York south through the Appalachians and the Piedmont to the Florida Panhandle, and west through the Ohio and Mississippi valleys to Illinois, Missouri, eastern Kansas, southeastern Nebraska, eastern Oklahoma and eastern Texas. It does not reach peninsular Florida, and it never recolonized most of the land north of the glacial limit after the last ice age.

Within that range it is a habitat generalist. In the Northeast and the Appalachians it favors deciduous and mixed woodland on hilly ground with rocky outcrops, ledges and fallen logs. On the southern coastal plain it lives in low, damp woods and along swamp edges, and in Gulf Coast states it also occupies pine forest. It adapts well to people, turning up in wooded suburbs, woodpiles, old sawdust and brush piles, stone walls and the edges of gardens.

In winter copperheads brumate (the reptile version of hibernation) in rock crevices, old mines, hollow logs, stumps and building foundations, often on south- or west-facing slopes. These dens are frequently shared with timber rattlesnakes, rat snakes and racers.

The 2015 split: one copperhead becomes two

For decades the copperhead was treated as one species with five subspecies: the northern, southern, Osage, broad-banded and Trans-Pecos copperheads. A genetic study by Frank Burbrink and Timothy Guiher, published in 2015, found that these subspecies did not match real evolutionary lineages.

Most herpetologists now recognize two species. The eastern copperhead (Agkistrodon contortrix) includes the former northern, southern and Osage copperheads. The broad-banded copperhead (Agkistrodon laticinctus), which includes the former Trans-Pecos copperhead, lives from southern Kansas and Oklahoma through central and western Texas into northern Mexico. As its name suggests, it has wider, bolder crossbands. This profile focuses on the eastern copperhead, but the two are very similar in behavior and venom.

Diet and hunting

Copperheads are carnivores with a broad menu. Adults eat mainly small mammals such as mice and voles, plus lizards, small snakes, frogs, salamanders and occasionally small birds. Young copperheads eat a higher share of invertebrates, lizards and frogs.

Insects matter more than most people expect. Copperheads eat many caterpillars, and in summer they gather where cicadas emerge from the ground, catching the soft-bodied adults as they crawl up tree trunks. Herpetologists in Texas have reported copperheads climbing well up into bushes and trees to reach them.

Most of the time the copperhead is an ambush predator. It picks a spot along a log or at the edge of a trail, coils in the leaf litter and waits, sometimes for days. The heat-sensing pits let it strike accurately at warm-bodied prey even in darkness. Small prey is held in the mouth until it dies, while larger rodents are bitten, released and then tracked by scent. Copperheads eat surprisingly little: one tracked snake took just eight meals in a whole active season, adding up to only about one and a quarter times its own body weight.

Juveniles use their yellow tail tip as a lure. Lying still, the young snake wriggles its tail like a caterpillar or worm, and frogs or lizards that come to investigate are struck. This behavior is called caudal luring.

Behavior

Copperheads are mostly solitary. In the north they are active from about April to early November; in the South the season is longer, and they may bask on warm winter days. They are active by day in spring and fall, but in the heat of summer they become largely nocturnal, hunting on warm nights.

Their main defense is camouflage. On dead leaves or red clay a motionless copperhead is extremely hard to see, so instead of fleeing like many snakes, it often freezes. This is why people so often walk past, or step on, one without noticing it. If disturbed, a copperhead may vibrate its tail rapidly, which can make a buzzing sound in dry leaves, release a strong-smelling musk from glands at the base of its tail, or strike as a last resort. To learn more about that musk, see do copperheads smell like cucumbers?

In the breeding season, rival males wrestle for access to females, raising the front of their bodies and pushing against each other until one gives up. They do not bite each other.

Reproduction, life cycle and lifespan

Copperheads mate mainly in spring, from about February to May, and again in late summer and early fall, from about August to October. Females can store sperm over the winter and use it to fertilize their eggs the following spring.

The copperhead is viviparous: instead of laying eggs, the female carries the developing young inside her body and gives birth to live babies, usually from late August to early October. Gestation averages roughly three to four months. A typical litter has 4 to 8 young, but litters of 1 to about 20 have been recorded, and larger, older females tend to have more. Each newborn is about 20 cm (8 in) long, weighs about 10 g (0.35 oz) and has working fangs and venom from birth. The mother gives no care after the young disperse.

Copperheads reach maturity at about 3 to 4 years old, and females often skip a year or two between litters. Remarkably, copperheads are also capable of facultative parthenogenesis, meaning a female can occasionally produce offspring without mating. This has been documented in captive females and in wild populations.

Copperheads are long-lived for their size. Studies of a wild population in Kansas projected a maximum lifespan of about 15 years, and the oldest wild copperhead on record was about 18 years old. In zoos and other captive collections, copperheads have lived 20 to 29 years.

Venom and bites

Copperhead venom is mainly hemotoxic and cytotoxic, which means it damages blood vessels and the tissue around the bite, causing pain and swelling. In laboratory tests it is among the least potent venoms of any pit viper. Copperheads often give a warning bite with little or no venom, and dry bites, with no venom injected at all, are common.

Because copperheads are common and often live close to people, they cause more venomous snakebites than any other snake in the United States. The CDC estimates that 7,000 to 8,000 people are bitten by venomous snakes in the US each year and that about five die; deaths from copperhead bites are extremely rare. Bites can still be very painful and cause lasting damage to a hand or foot, so any bite is a medical emergency: seek emergency medical help immediately or call 911. The full picture is in are copperheads venomous?

Predators and conservation

Copperheads have many enemies, especially when young. Kingsnakes are well-known predators, and racers, hawks, owls, Virginia opossums and American bullfrogs also eat them. Some researchers have linked high local numbers of copperheads to declines in kingsnakes.

The IUCN Red List classes the copperhead as Least Concern, with a stable population, because it is widespread and common over much of its range. Locally the situation is different: at the northern edge of the range, in parts of New England, it is rare and protected. Habitat loss, road deaths and people killing snakes out of fear are the main threats. Studies show that copperheads in fragmented habitats often stay within a single patch, which can cut them off from feeding areas and winter dens.

Myths and facts

Myth: baby copperheads are more dangerous than adults. A newborn has the same kind of venom, but much less of it, and there is no good evidence that young snakes “cannot control” their venom.

Myth: copperheads chase people. A copperhead that seems to move toward someone is usually trying to reach cover. Their instinct is to stay still or slip away.

Myth: copperheads always travel in pairs. They are solitary for most of the year; seeing two together usually means a breeding encounter or a shared basking spot.

Myth: harmless snakes with blotches are copperheads. Corn snakes, young rat snakes, milk snakes and water snakes are often mistaken for copperheads and killed. Compare the patterns in copperhead vs corn snake, and see the other species to know in venomous snakes in the US.

Relationship with people

The copperhead is part of American folklore and history; its name was even used as a nickname for Northern Democrats who opposed the Civil War. Its scientific name reflects its pattern: contortrix comes from Latin for “twisted” or “intricate,” a reference to its pinched crossbands.

Medical researchers have also studied its venom. A protein called contortrostatin, isolated from copperhead venom, slowed the growth and spread of tumors in laboratory mice, although it has not become a human treatment. For most people, though, the copperhead is simply a neighbor in the woods: an animal that keeps rodent and insect numbers in check and that is best admired from a respectful distance and left alone.