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New Jersey Endangered and Threatened Species Field Guide
Agkistrodon contortrix mokasen
Species Group: Reptile
State: Special Concern
The northern copperhead is one of two venomous species of snake found in New Jersey (the other being the timber rattlesnake). It may grow to a length of 22-53 inches. When alarmed, it may violently vibrate its tail. When the vibrating tail strikes vegetation, it may sound like a rattle, but this species does not have a rattle on its tail.
The copperhead is two shades of copper or reddish-brown. Its head is a solid copper color. The darker shade forms an hourglass shape over the lighter background, with the wider portion of the hourglass on the side of the snake while the narrow portion is on the snake’s back. The snake’s coloration is excellent camouflage when it lies in leaf litter.
Young copperheads, known as “neonates” are paler in color that the adults. Neonates also have a yellow-tipped tail that acts as a lure for prey.
The non-venomous and common northern water snake (Nerodia sipedon sipedon) is sometimes confused with the copperhead because they have similar colors. Both snakes also have hourglass-shaped bands on their bodies. On the water snake though, the darker-color bands are widest along its back and narrow along its sides.
DISTRIBUTION AND HABITAT
The range of the northern copperhead extends from Massachusetts in the north and east to Illinois in the west and Georgia and Alabama in the south.
In New Jersey, copperheads are found only in the northern portion of the state, from the Sourlands of Hunterdon, Mercer, and Somerset Counties in the south to the New Jersey/New York border in the north. They may also be found within the Palisades in Bergen County.
Within their range, copperheads may inhabit rocky wooded hillsides, rocky fields, berry thickets, wooded wetlands, farmlands, and even old mulch piles.
Copperheads feed mostly on small mammals such as mice. They will also eat small birds, other reptiles, amphibians, and insects. Hidden by its camouflaged scales, the copperhead sits and waits for prey, lying motionless before striking with its venomous bite. Females which are about to give birth (known as being gravid) will usually not eat.
Copperheads are primarily active in New Jersey between the months of May through October. During the winter, they will hibernate or den underground, within rocky areas, in animal burrows, or within hollow logs or stumps. They may den in large groups and with other species of snakes, including rattlesnakes. Copperheads give birth to 6-17 young in mid-August to early October.
During the spring and fall, they are most active during the day. In summer, they may become more nocturnal.
CURRENT STATUS, THREATS, AND CONSERVATION
New Jersey’s copperhead population has declined over the last fifty years due to a number of reasons including habitat loss and fragmentation, illegal collecting, being run-over by cars, and human persecution. This species, as well as the rattlesnake, have an undeserved bad reputation and are often killed, which is illegal in New Jersey.
Due to population declines and habitat loss, the copperhead was listed as a Species of Special Concern in New Jersey. Because of the secretive nature and patchy distribution of copperheads, we still have much to learn about their biology and population status in New Jersey. Research needs to be completed to find additional den sites, check existing dens, and determine whether the population might be decreasing or increasing and by how much.
Although copperheads are venomous, no one has ever died from a copperhead bite in New Jersey. They will not chase people, but they will defend themselves if they feel that they are in danger.
In 2016, the New Jersey Endangered and Nongame Advisory Committee recommended changing this species' status from Special Concern to Threatened within the state, but no formal rule proposal has been filed to date.
Text written by Michael J. Davenport in 2011; updated in 2016.
Species: A. contortrix mokasen
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