Northern Cottonmouth

Agkistrodon piscivorus is a species of venomous snake, a pit viper in the subfamily Crotalinae of the family Viperidae. It is one of the world's few semiaquatic vipers (along with the Florida cottonmouth), and is native to the Southeastern United States. As an adult, it is large and capable of delivering a painful and potentially fatal bite. When threatened, it may respond by coiling its body and displaying its fangs. Individuals may bite when feeling threatened or being handled in any way. It tends to be found in or near water, particularly in slow-moving and shallow lakes, streams, and marshes. It is a capable swimmer, and like several species of snakes, is known to occasionally enter bays and estuaries and swim between barrier islands and the mainland.

The generic name is derived from the Greek words ἄγκιστρον agkistron "fish-hook, hook" and ὀδών odon "tooth", and the specific name comes from the Latin piscis 'fish' and voro '(I) eat greedily, devour'; thus, the scientific name translates to "hook-toothed fish-eater". Common names include cottonmouth, northern cottonmouth, water moccasin, swamp moccasin, black moccasin, and simply viper. Many of the common names refer to the threat display, in which this species often stands its ground and gapes at an intruder, exposing the white lining of its mouth. Many scientists dislike the use of the term water moccasin since it can lead to confusion between the venomous cottonmouth and nonvenomous water snakes.

Taxonomy and etymology

Common names

This is a list of common names for A. piscivorus, some of which also refer to other species:

Subspecies and taxonomic history

For many decades, one species with three subspecies were formally recognized: eastern cottonmouth, A. p. piscivorus (Lacépède, 1789); western cottonmouth, A. p. leucostoma (Troost, 1836); and Florida cottonmouth, A. p. conanti Gloyd, 1969. However, a molecular DNA-based study was published in 2014, applying phylogenetic theories (one implication being no subspecies are recognized), changing the long-standing taxonomy. The resulting and current taxonomic arrangement recognizes two species and no subspecies. The western cottonmouth (A. p. leucostoma) was synonymized with the eastern cottonmouth (A. p. piscivorus) into one species (with the oldest published name, A. p. piscivorus, having priority). The Florida cottonmouth (A. p. conanti) is now recognized as a separate species.

Agkistrodon piscivorus (Lacépéde, 1789), northern cottonmouth

Agkistrodon conanti Gloyd, 1969, Florida cottonmouth (south Georgia and Florida peninsula)

Anatomy and description

Agkistrodon piscivorus is the largest species of the genus Agkistrodon. Adults commonly exceed 80 cm (31 in) in total length (including tail); females are typically smaller than males. Total length, per one study of adults, was 65 to 90 cm (26 to 35 in). Average body mass has been found to be 292.5 to 579.6 g (10.32 to 20.44 oz) in males and 201.1 to 254.1 g (7.09 to 8.96 oz) in females. Occasionally, individuals may exceed 180 cm (71 in) in total length, especially in the eastern part of the range, with a record specimen of 189.2 cm (74.5 in).