Cottonmouth Fact File

Cottonmouth (Agkistrodon piscivorus)

Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Suborder: Serpentes
Family: Viperidae
Subfamily: Crotalinae
Genus: Agkistrodon
Species: Cottonmouth
(Agkistrodon piscivorus)

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What does the name mean? The name has both Greek and Latin origin. The name Agkistrodon is derived from the Greek words ancistro, meaning "hook" or "curved", and odon meaning "tooth". The name Agkistrodon literally means "Hooked tooth", which probably refers to the snakes' fangs.
Piscivorus has Latin origin, and is derived from the words piscis meaning "fish", and voro meaning "to eat".
Agkistrodon piscivorus literally translates into "hooked tooth fish eater".

Description: These snakes generally average between 76cm - 1.23m (2.49ft - 4.0ft) in length. Individuals attaining lengths of 1.8m (5.9ft) have been found occasionally. The record for this snake is 1.88m (6.16ft). Cottonmouths are the largest species in the genus Agkistrodon
The colouration of this species varies slightly depending on its geographic distribution. Colours range from dark olive brown, grey, brown, and even black with 10-17 dark crossbands extending down the back. These colours normally fade with age.
In comparison to the adults, juveniles are brightly coloured with distinct crossbands and a bright yellow tail.
The underside, or belly, is a yellowish white becoming darker towards the tail. The belly is also marked with dark spots at irregular intervals.
These snakes have a distinct triangular head with a dark line through the eye.
The scales are heavily keeled giving the snake a very rough appearance.
The almost pure white colouration of the inside of the mouth gives this species its common name.
The name Water moccasin, or moccasin is also often used when referring to this species.

Juvenile cottonmouth

Venom: The venom of this snake is predominantly Cytotoxic causing severe tissue damage near the site of the wound. Like most members of the Viperidae family the venom also contains haemotoxic properties which breaks down and destroys red blood cells.
A typical bite may yield 142mg of venom of which 113mg is classified as fatal in humans, however, bites and fatalities are rare in this species.

Distribution: Found throughout the eastern and southeastern United States. This includes Florida, eastern and southeastern Texas, Georgia, Indiana, Illinois, Louisiana, Mississippi, Missouri, Kentucky and Alabama.

Habitat: True to its name this species is usually associated with water. It is generally regarded as the most aquatic pitviper of the genus Agkistrodon. Cottonmouths are fairly common wherever there is suitable habitat. This species may be found in swamps, marshes, rivers, streams, lakes, ponds, and man made dams and drainwater ditches.


Habits: Cottonmouths are classified as being active both during the day and night, although records show that they are predominantly active at night. Like all snakes, this species must maintain a high body temperature to help with their digestive metabolism which is not condusive to an aqautic lifestyle (heat loss occurs faster in water than air). This explains why the species may often be seen basking during the day.
This species "aggressive" nature is unfounded. Although temperaments vary from one individual to another studies have shown that most will try to escape rather than risk confrontation. This species has a wide range of defensive threat displays designed specifically to avoid confrontation.
Just as a cobra spreads a hood, cottonmouths will "gape", exposing the white mouth, fangs exposed, advertising its toxicity to any conceived threat or would-be predator. Another defensive display includes vibrating the tail, similar to rattlesnakes, as a warning. When confronted these snake may also flatten their bodies and emit a foul smelling secretion from the anal glands as a deterrent. All these "tactics" are clear indications of non-aggressive behaviour.
Hibernation in cottonmouths has been documented depending on its geographical location. In the northern parts of its range this species will hibernate during the winter months, however in the southern parts of its range where winters are a lot milder, hibernation in the species may not occur at all.
One of the most interesting habits of the species occurs in juveniles. The bright yellow tail is used as a caudal "lure" to entice prey within striking distance.

Reproduction: All members of the Viperidae family are ovoviviparous. Ovoviviparity means that the young develop within an egg, and are nourished by the egg yolk, but instead of being incubated externally, the eggs are retained within the organisms body until they are ready to hatch. Female cottonmouths typically give birth to between 1-16 neonates. The young measure approximately 22-35cm (8.6-13.7inches).
Breeding usually takes place in Spring. Ritualised combat behaviour has been documented in males which is important in sexual selection.
Prior to reproduction, males will gently nudge the female along the back and sides until she opens her cloaca and fertilization takes place. This "foreplay" may continue for several hours prior to mating.
After a gestation period of three to four months the neonates emerge.
Sexual maturity is reached within three years depending on the growth rate.

Diet: Both warm and cold-blooded prey is taken. Prey items may include other snakes, frogs, fish, salamanders, birds, amphibians, lizards, turtles, and even small alligators. The majority of prey taken consists of frogs and fish, hence the scentific name piscivorus. Cannibalism within the species has also been documented on several occasions.
Smaller prey such as fish and frogs are held in the jaws until the venom takes effect. Large prey items are released immeadiately after envenomation, thus reducing the risk of injury whilst the venom has its effect, and then subsequently "tracked" by scent.
Their wide and varied diet make these snakes easy to care for in captivity.

Subspecies: There are three known subspecies:
Agkistrodon piscivorus conanti - Florida cottonmouth.
Agkistrodon piscivorus piscivorus - Eastern cottonmouth.
Agkistrodon piscivorus leucostoma - Western cottonmouth.

Conservation Status

ICUN Red List: least concern

CITES: Not listed

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Recommended books

Snakes Of The Southeast (Wormsloe Foundation Nature Book)is an exquisite book...on the herpetofauna of the southeastern United States.
The Venomous Reptiles of the Western Hemisphere, 2 Vol. Set (Comstock Books in Herpetology) This book is an absolute must.

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