Common names: western cottonmouth, water moccasin, cottonmouth, more.

Agkistrodon piscivorus leucostoma is a venomous

Venomous snake

"Poisonous snake" redirects here. For true poisonous snakes, see Rhabdophis.Venomous snakes are snakes which have venom glands and specialized teeth for the injection of venom...

 pitviper

Crotalinae

The Crotalinae, commonly known as "pit vipers" or crotaline snakes, are a subfamily of venomous vipers found in Asia and the Americas. They are distinguished by the presence of a heat-sensing pit organ located between the eye and the nostril on either side of the head...

 subspecies

Subspecies

Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...

 found in the south central United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

. It is the smallest of the three subspecies and tends to be darker in color.

Description

This is the smallest of the three subspecies, both in maximum length and especially in average length. The two maximum lengths ever reported were both 62 inches (157.5 cm): the first by Wright and Wright (1957) and the second by David L. Edwards for a specimen killed north of Yazoo City in Mississippi

Mississippi

Mississippi is a U.S. state located in the Southern United States. Jackson is the state capital and largest city. The name of the state derives from the Mississippi River, which flows along its western boundary, whose name comes from the Ojibwe word misi-ziibi...

 almost 30 years later. Regarding the average length, a study by Clarke (1949) of 100 specimens showed that 86 were less than 42 inches (106.7 cm) long and 64 were less than 36 inches (91.4 cm). In another study by Barbour (1956) of 167 specimens from western Kentucky

Kentucky

The Commonwealth of Kentucky is a state located in the East Central United States of America. As classified by the United States Census Bureau, Kentucky is a Southern state, more specifically in the East South Central region. Kentucky is one of four U.S. states constituted as a commonwealth...

, the largest was only 39 inches (99.3 cm) and the average size was 27.5 inches (70 cm).

Coloration is similar to the two eastern subspecies, except that most specimens tend to become darker at a younger age. Also, the light line that borders the dark cheek strip—clearly defined in A. p. conanti and less so in A. p. piscivorus

Agkistrodon piscivorus

Agkistrodon piscivorus is a venomous snake, a species of pit viper, found in the southeastern United States. Adults are large and capable of delivering a painful and potentially fatal bite. When antagonized they will stand their ground by coiling their bodies and displaying their fangs...

 -- is usually not present in this subspecies. A dorsal color pattern consists of 10 to 15 dark crossbands can be seen in small specimens, as well as in some larger ones.

Common names

Western cottonmouth, water moccasin, cottonmouth, (black) moccasin, blunt-tail moccasin, (northern) cottenmouth moccasin, stump-tail (water) moccasin, viper, western cottonmouth moccasin, cotton-mouthed snake, Congo snake, trap-jaw, gapper.

Geographic range

Found in the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

, from southern Alabama

Alabama

Alabama is a state located in the southeastern region of the United States. It is bordered by Tennessee to the north, Georgia to the east, Florida and the Gulf of Mexico to the south, and Mississippi to the west. Alabama ranks 30th in total land area and ranks second in the size of its inland...

 along coast of the Gulf of Mexico

Gulf of Mexico

The Gulf of Mexico is a partially landlocked ocean basin largely surrounded by the North American continent and the island of Cuba. It is bounded on the northeast, north and northwest by the Gulf Coast of the United States, on the southwest and south by Mexico, and on the southeast by Cuba. In...

, including many offshore islands, to southeastern and central Texas

Texas

Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...

 and north to Oklahoma

Oklahoma

Oklahoma is a state located in the South Central region of the United States of America. With an estimated 3,751,351 residents as of the 2010 census and a land area of 68,667 square miles , Oklahoma is the 28th most populous and 20th-largest state...

, Missouri

Missouri

Missouri is a US state located in the Midwestern United States, bordered by Iowa, Illinois, Kentucky, Tennessee, Arkansas, Oklahoma, Kansas and Nebraska. With a 2010 population of 5,988,927, Missouri is the 18th most populous state in the nation and the fifth most populous in the Midwest. It...

, Illinois

Illinois

Illinois is the fifth-most populous state of the United States of America, and is often noted for being a microcosm of the entire country. With Chicago in the northeast, small industrial cities and great agricultural productivity in central and northern Illinois, and natural resources like coal,...

 Indiana

Indiana

Indiana is a US state, admitted to the United States as the 19th on December 11, 1816. It is located in the Midwestern United States and Great Lakes Region. With 6,483,802 residents, the state is ranked 15th in population and 16th in population density. Indiana is ranked 38th in land area and is...

 and southeastern Nebraska

Nebraska

Nebraska is a state on the Great Plains of the Midwestern United States. The state's capital is Lincoln and its largest city is Omaha, on the Missouri River....

. The type locality given is "western district of Tennessee." Schmidt (1953) proposed that this be emended to "10 miles northeast of Bolivar, Hardeman County, Tennessee."

External links

• A. piscivorus at Herps of Texas. Accessed 31 May 2007.
• A. p. leucostoma at The Center for Reptile and Amphibian Conservation and Management. Accessed 31 May 2007.
• A. p. leucostoma at Texas Parks & Wildlife. Accessed 31 May 2007.
• A. p. leucostoma at Houston Herpetological Supply. Accessed 31 May 2007.
• A. p. leucostoma at Snakes of Louisiana. Accessed 31 May 2007.
• A. p. leucostoma at Saint Louis Zoo. Accessed 31 May 2007.