Northern Cottonmouth (also known as a Water Moccasin)
Agkistrodon piscivorus • Order: Squamata, Suborder: Serpentes, Family: Viperidae, Subfamily: Crotalinae, Genus: Agkistrodon, Species: Agkistrodon piscivorus
Natural range includes the Southeastern United States, from southeastern Virginia south to Florida, and west to eastern Texas and Oklahoma. This specimen appears within the typical range for the species.
Look up Northern Cottonmouth (also known as a Water Moccasin) in the Snake Encyclopedia →Venomous Status
Venomous (Solenoglyphous fangs)
Danger Level
Extremely Dangerous - While bites are rarely fatal with modern medical treatment, the venom is potent enough to cause permanent tissue damage, limb loss, or severe systemic complications if not treated immediately.
Family
Order: Squamata, Suborder: Serpentes, Family: Viperidae, Subfamily: Crotalinae, Genus: Agkistrodon, Species: Agkistrodon piscivorus
Conservation
IUCN Red List: Least Concern. Major threats include habitat destruction through the draining of wetlands and persecution by humans due to fear and misinformation.
Physical Description
Heavy-bodied snake with a broad, spade-shaped head. This individual shows dark brown to blackish ground color with crossing bands that are often darker on the edges. Features a dark stripe through the eye masked by a lighter coloration above. The scales are strongly keeled, and the pupils are vertical (elliptical).
Size & Dimensions
This specimen appears to be an adult approximately 30-40 inches (76-101 cm) in length. Species average is 30-48 inches, with a maximum recorded length of 74 inches.
Habitat
Semiaquatic pit viper found in swamps, marshes, drainage ditches, and the edges of ponds, lakes, and sluggish streams. They prefer areas with abundant cover such as vegetation or logs, and can be found at elevations from sea level to roughly 500 meters.
Behavior & Temperament
Often defensive rather than aggressive. Known for its 'threat display' where it coils and opens its mouth wide to reveal a white, cotton-like interior. They are semi-aquatic and active both day and night depending on temperature, though primarily nocturnal during the heat of summer.
Diet & Feeding
Opportunistic carnivore. Feeds on fish, amphibians, lizards, other snakes (including other pit vipers), small mammals, and birds. They utilize both ambush hunting and active foraging, employing a 'bite and release' strategy for larger prey.
Reproduction
Ovoviviparous (gives birth to live young). Typical litter size is 6 to 10 neonates, though it can range from 1 to 20. Breeding occurs in spring, with births typically occurring in late summer or early fall every second or third year.
Venom Profile
Highly hemotoxic and cytotoxic venom which causes tissue destruction, edema (swelling), and coagulation issues.
Look-alikes
Often confused with non-venomous Water Snakes (genus Nerodia). Nerodia species lack the facial pit, have round pupils, and typically lack the blunt, blocky head shape of Agkistrodon. Also similar to the Copperhead (Agkistrodon contortrix), which has a more 'Hershey Kiss' or hourglass-shaped pattern and lacks the dark eye-stripe.
Conservation Status
IUCN Red List: Least Concern. Major threats include habitat destruction through the draining of wetlands and persecution by humans due to fear and misinformation.
Cultural Significance
Ecologically vital as an apex predator in wetland ecosystems, helping to regulate populations of fish and rodents. Historically feared and misunderstood in Southern folklore, often leading to unprovoked killing of both this species and harmless water snakes.
Notable Features
One of the world's only semi-aquatic vipers. Features heat-sensing loreal pits located between the eye and nostril, allowing it to strike accurately at warm-blooded prey in total darkness. The white lining of the mouth provides a startling visual warning to potential predators.