Northern Water Snake
Encyclopedia
The Northern water snake (Nerodia sipedon) is a large, nonvenomous, well-known snake
Snake
Snakes are elongate, legless, carnivorous reptiles of the suborder Serpentes that can be distinguished from legless lizards by their lack of eyelids and external ears. Like all squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales...

 in the Colubrid
Colubrid
A colubrid is a member of the snake family Colubridae. This broad classification of snakes includes about two-thirds of all snake species on earth. The earliest species of the snake family date back to the Oligocene epoch. With 304 genera and 1,938 species, Colubridae is the largest snake family...

ae family that is native to North America.

Behavior

They are active during the day and at night. They are most often seen basking on rocks, stumps, or brush. During the day, they hunt among plants at the water's edge, looking for small fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...

, frog
Frog
Frogs are amphibians in the order Anura , formerly referred to as Salientia . Most frogs are characterized by a short body, webbed digits , protruding eyes and the absence of a tail...

s, worm
Worm
The term worm refers to an obsolete taxon used by Carolus Linnaeus and Jean-Baptiste Lamarck for all non-arthropod invertebrate animals, and stems from the Old English word wyrm. Currently it is used to describe many different distantly-related animals that typically have a long cylindrical...

s, leech
Leech
Leeches are segmented worms that belong to the phylum Annelida and comprise the subclass Hirudinea. Like other oligochaetes such as earthworms, leeches share a clitellum and are hermaphrodites. Nevertheless, they differ from other oligochaetes in significant ways...

es, crayfish
Crayfish
Crayfish, crawfish, or crawdads – members of the superfamilies Astacoidea and Parastacoidea – are freshwater crustaceans resembling small lobsters, to which they are related...

, salamander
Salamander
Salamander is a common name of approximately 500 species of amphibians. They are typically characterized by a superficially lizard-like appearance, with their slender bodies, short noses, and long tails. All known fossils and extinct species fall under the order Caudata, while sometimes the extant...

s, small bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...

s and mammal
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...

s. At night, they concentrate on minnow
Minnow
Minnow is a general term used to refer to small freshwater and saltwater fish, especially those used as bait fish or for fishing bait. More specifically, it refers to small freshwater fish of the carp family.-True minnows:...

s and other small fish sleeping in shallow water. The Lake Erie water snake subspecies, Nerodia sipedon insularum, was once endangered, but now benefits from the introduction of the round goby
Round goby
The round goby, Neogobius melanostomus, is an euryhaline bottom-dwelling goby of the family Gobiidae, native to central Eurasia including the Black Sea and the Caspian Sea.-Characteristics:...

, an invasive species
Invasive species
"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....

, which now comprises up to 90 per cent of its diet.

Subspecies

Ordered alphabetically.
  • N. s. insularumLake Erie
    Lake Erie
    Lake Erie is the fourth largest lake of the five Great Lakes in North America, and the tenth largest globally. It is the southernmost, shallowest, and smallest by volume of the Great Lakes and therefore also has the shortest average water residence time. It is bounded on the north by the...

     water snake
  • N. s. pleuralis
    Nerodia sipedon pleuralis
    The Midland Water Snake is a subspecies of the Northern Water Snake. This snake lives in habitats such as streams, ponds, swales, and marshes. In the southern US it follows river valleys....

    – Midland water snake
  • N. s. sipedon – Northern water snake
  • N. s. williamengelsi – Carolina water snake

Description

The Northern water snake can grow up to 135 cm (4.4 ft) long. They can be brown, gray, reddish, or brownish-black. They have dark crossbands on their necks and dark stripes and blotches on the rest of their bodies, often leading to misidentification as cottonmouths
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...

 or copperheads
Agkistrodon contortrix
Agkistrodon contortrix is a species of venomous snake found in North America, a member of the Crotalinae subfamily. The more common name for the species is "copperhead". The behavior of Agkistrodon contortrix may lead to accidental encounters with humans...

 by novices. They darken as they age. Some will become almost completely black. The belly of this snake also varies in color. It can be white, yellow, or gray. Usually it also has reddish or black crescents.

Reproduction

Northern water snakes mate from April through June. They are ovoviviparous (live-bearers), which means they do not lay eggs like many other snakes. Instead, the mother carries the eggs inside her body and gives birth to free living young, each one 19–23 cm (7.5–9.1 in) long. A female may have as many as thirty young at a time. They are born between August and October. Mothers do not care for their young; as soon as they are born, they are on their own.

Defense against predators

Northern water snakes have many predators, including birds, raccoon
Raccoon
Procyon is a genus of nocturnal mammals, comprising three species commonly known as raccoons, in the family Procyonidae. The most familiar species, the common raccoon , is often known simply as "the" raccoon, as the two other raccoon species in the genus are native only to the tropics and are...

s, opossums, fox
Fox
Fox is a common name for many species of omnivorous mammals belonging to the Canidae family. Foxes are small to medium-sized canids , characterized by possessing a long narrow snout, and a bushy tail .Members of about 37 species are referred to as foxes, of which only 12 species actually belong to...

es, snapping turtle
Snapping turtle
The common snapping turtle is a large freshwater turtle of the family Chelydridae. Its natural range extends from southeastern Canada, southwest to the edge of the Rocky Mountains, as far east as Nova Scotia and Florida and as far southwest as northeastern Mexico...

s, and other snakes. They defend themselves vigorously when they are threatened. If they are picked up by an animal, or person, they will bite repeatedly, as well as release excrement and musk
Musk
Musk is a class of aromatic substances commonly used as base notes in perfumery. They include glandular secretions from animals such as the musk deer, numerous plants emitting similar fragrances, and artificial substances with similar odors. Musk was a name originally given to a substance with a...

. Their saliva
Saliva
Saliva , referred to in various contexts as spit, spittle, drivel, drool, or slobber, is the watery substance produced in the mouths of humans and most other animals. Saliva is a component of oral fluid. In mammals, saliva is produced in and secreted from the three pairs of major salivary glands,...

 contains a mild anticoagulant
Anticoagulant
An anticoagulant is a substance that prevents coagulation of blood. A group of pharmaceuticals called anticoagulants can be used in vivo as a medication for thrombotic disorders. Some anticoagulants are used in medical equipment, such as test tubes, blood transfusion bags, and renal dialysis...

, which can cause the bite to bleed more but poses little risk to humans.

Hibernation

Northern water snakes often share winter dens with copperheads
Agkistrodon contortrix
Agkistrodon contortrix is a species of venomous snake found in North America, a member of the Crotalinae subfamily. The more common name for the species is "copperhead". The behavior of Agkistrodon contortrix may lead to accidental encounters with humans...

 and black rat snakes.

Habitats

Muskrat
Muskrat
The muskrat , the only species in genus Ondatra, is a medium-sized semi-aquatic rodent native to North America, and introduced in parts of Europe, Asia, and South America. The muskrat is found in wetlands and is a very successful animal over a wide range of climates and habitats...

 houses and beaver
Beaver
The beaver is a primarily nocturnal, large, semi-aquatic rodent. Castor includes two extant species, North American Beaver and Eurasian Beaver . Beavers are known for building dams, canals, and lodges . They are the second-largest rodent in the world...

 lodges are good places to find water snakes, which like to hide among the sticks and plant stems. They live near lakes, ponds, marshes, rivers, and canals; just about anywhere there is freshwater.

The Lake Erie water snake subspecies (Nerodia sipedon insularum), which occurs mainly on the lake's western islands offshore from Ohio
Ohio
Ohio is a Midwestern state in the United States. The 34th largest state by area in the U.S.,it is the 7th‑most populous with over 11.5 million residents, containing several major American cities and seven metropolitan areas with populations of 500,000 or more.The state's capital is Columbus...

 and Ontario
Ontario
Ontario is a province of Canada, located in east-central Canada. It is Canada's most populous province and second largest in total area. It is home to the nation's most populous city, Toronto, and the nation's capital, Ottawa....

, recovered to the point where on August 16, 2011 the U.S. Fish and Wildlife Service removed it from the Federal List of Endangered and Threatened Wildlife. The subspecies was first listed as threatened in 1999 after a decline due to eradication by humans, as well as habitat loss and degradation. When initially listed, the subspecies’ population had dropped to only 1,500 adults. Endangered Species Act
Endangered Species Act
The Endangered Species Act of 1973 is one of the dozens of United States environmental laws passed in the 1970s. Signed into law by President Richard Nixon on December 28, 1973, it was designed to protect critically imperiled species from extinction as a "consequence of economic growth and...

 (ESA) protections for the snake included designation of 300 acres of inland habitat and 11 miles of shoreline for breeding grounds. Ironically, the introduction of an invasive species, the Eurasian Round goby
Round goby
The round goby, Neogobius melanostomus, is an euryhaline bottom-dwelling goby of the family Gobiidae, native to central Eurasia including the Black Sea and the Caspian Sea.-Characteristics:...

(Neogobius melanostomus) into Lake Erie in the mid-1990s became a new food source for the Lake Erie water snake. By 2009, the population recovered to 11,980 snakes, safely exceeding the population minimum goal of 5,555 adult snakes required by the 2003 recovery plan. Monitoring will occur for 5 years following this delisting. The Lake Erie water snake is just the 23rd species to be removed from the list due to recovery.

External links


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