The smooth green snake (''Opheodrys vernalis'') is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

n nonvenomous snake in the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Colubridae Colubridae (, commonly known as colubrids , from la, coluber, 'snake') is a family of snakes. With 249 genera, it is the largest snake family. The earliest species of the family date back to the Oligocene epoch. Colubrid snakes are found on ever ...

. The species is also referred to as the grass snake. It is a slender, "small medium" snake that measures as an adult. It gets its common name from its smooth dorsal scales, as opposed to the

rough green snake ''Opheodrys aestivus'', commonly known as the rough green snake, is a nonvenomous North American colubrid. It is sometimes called grass snake or green grass snake, but these names are more commonly applied to the smooth green snake ('' Opheodry ...

, which has keeled dorsal scales. The smooth green snake is found in marshes, meadows, open woods, and along stream edges, and is native to regions of

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...

, the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

, and northern

Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

. A non-aggressive snake, it seldom bites and usually flees when threatened. It mates in late spring to summer, and females lay their eggs from June to September. Smooth green snakes will often bob their heads in order to mimic vegetation blowing in the wind.

Description

The smooth green snake is slender. In size, it is classified as a "small medium" snake, reaching to in total length (including tail) as an adult. The longest smooth green snake was measured as being in total length. The tail makes up about 1/4 to 1/2 the total length of the snake; males have longer tails than females. It is uniform light green on its back, with a yellow or white belly, and has smooth

dorsal scales In snakes, the dorsal scales are the longitudinal series of plates that encircle the body, but do not include the ventral scales. Campbell JA, Lamar WW (2004). ''The Venomous Reptiles of the Western Hemisphere''. Ithaca and London: Comstock Publis ...

, unlike those of the rough green snake, which are keeled. Its smooth dorsal scales are arranged in 15 rows at midbody. At birth, its

dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage * Dorsal co ...

coloration is different from that when it matures. At first, it can be olive green, blue-gray, or even brown, but after it sheds its skin for the first time, it becomes the characteristic bright green. The dorsal coloration can also vary depending on location: bluish in

Kansas Kansas () is a state in the Midwestern United States. Its capital is Topeka, and its largest city is Wichita. Kansas is a landlocked state bordered by Nebraska to the north; Missouri to the east; Oklahoma to the south; and Colorado to the ...

, olive-tinted light brown in southeastern Texas, and bronze in northern

Wisconsin Wisconsin () is a state in the upper Midwestern United States. Wisconsin is the 25th-largest state by total area and the 20th-most populous. It is bordered by Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake M ...

. It uses its tongue, red with a black end, by flicking it in and out of its mouth to "smell" what is around it. File:Smooth Green Snake.jpg, File:Smooth Green Snake (11856962215).jpg, File:Smooth green snake in gree tree opheodrys vernalis.jpg,

Subspecies

*Eastern smooth green snake, ''Opheodrys vernalis vernalis'' ( Harlan, 1827) *Western smooth green snake, ''Opheodrys vernalis blanchardi'' Grobman, 1941 *Northern smooth green snake, ''Opheodrys vernalis borealis'' Grobman, 1992

Etymology

The

subspecific name In zoological nomenclature, a subspecific name is the third part of a trinomen. In zoology there is only one rank below that of species, namely "subspecies". In botanical nomenclature, there are several levels of subspecific names, such as ''vari ...

, ''blanchardi'', is in honor of American herpetologist

Frank N. Blanchard Frank Nelson Blanchard (December 19, 1888 – September 21, 1937) was an American herpetologist, and professor of zoology at the University of Michigan from which institution he received his Ph.D. He is credited with describing several new subspec ...

Geographic range

The smooth green snake is native to the

Nearctic The Nearctic realm is one of the eight biogeographic realms constituting the Earth's land surface. The Nearctic realm covers most of North America, including Greenland, Central Florida, and the highlands of Mexico. The parts of North America t ...

region. The range spreads through southeastern

, west to

Saskatchewan Saskatchewan ( ; ) is a Provinces and territories of Canada, province in Western Canada, western Canada, bordered on the west by Alberta, on the north by the Northwest Territories, on the east by Manitoba, to the northeast by Nunavut, and on t ...

, and south through

Illinois Illinois ( ) is a U.S. state, state in the Midwestern United States, Midwestern United States. Its largest metropolitan areas include the Chicago metropolitan area, and the Metro East section, of Greater St. Louis. Other smaller metropolita ...

and

Virginia Virginia, officially the Commonwealth of Virginia, is a state in the Mid-Atlantic and Southeastern regions of the United States, between the Atlantic Coast and the Appalachian Mountains. The geography and climate of the Commonwealth ar ...

. It can also be found in other areas, such as in

Wyoming Wyoming () is a U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho to the west, Utah to the south ...

Colorado Colorado (, other variants) is a state in the Mountain West subregion of the Western United States. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the western edge of t ...

New Mexico ) , population_demonym = New Mexican ( es, Neomexicano, Neomejicano, Nuevo Mexicano) , seat = Santa Fe , LargestCity = Albuquerque , LargestMetro = Tiguex , OfficialLang = None , Languages = English, Spanish ( New Mexican), Navajo, Ker ...

Iowa Iowa () is a state in the Midwestern region of the United States, bordered by the Mississippi River to the east and the Missouri River and Big Sioux River to the west. It is bordered by six states: Wisconsin to the northeast, Illinois to the ...

Missouri Missouri is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. Ranking List of U.S. states and territories by area, 21st in land area, it is bordered by eight states (tied for the most with Tennessee ...

Texas Texas (, ; Spanish language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2 ...

, and

Northern Mexico Northern Mexico ( es, el Norte de México ), commonly referred as , is an informal term for the northern cultural and geographical area in Mexico. Depending on the source, it contains some or all of the states of Baja California, Baja California ...

Threats

''O. vernalis'' is hunted by various predators, including the

red-tailed hawk The red-tailed hawk (''Buteo jamaicensis'') is a bird of prey that breeds throughout most of North America, from the interior of Alaska and northern Canada to as far south as Panama and the West Indies. It is one of the most common members with ...

great blue heron The great blue heron (''Ardea herodias'') is a large wading bird in the heron family Ardeidae, common near the shores of open water and in wetlands over most of North America and Central America, as well as the Caribbean and the Galápagos ...

rough-legged buzzard The rough-legged buzzard or rough-legged hawk (''Buteo lagopus'') is a medium-large bird of prey. It is found in Arctic and Subarctic regions of North America, Europe, and Russia during the breeding season and migrates south for the winter. It ...

bear Bears are carnivoran mammals of the family Ursidae. They are classified as caniforms, or doglike carnivorans. Although only eight species of bears are extant, they are widespread, appearing in a wide variety of habitats throughout the Nor ...

raccoon The raccoon ( or , ''Procyon lotor''), sometimes called the common raccoon to distinguish it from other species, is a mammal native to North America. It is the largest of the procyonid family, having a body length of , and a body weight of ...

fox Foxes are small to medium-sized, omnivorous mammals belonging to several genera of the family Canidae. They have a flattened skull, upright, triangular ears, a pointed, slightly upturned snout, and a long bushy tail (or ''brush''). Twelve sp ...

es, and the common house

cat The cat (''Felis catus'') is a domestic species of small carnivorous mammal. It is the only domesticated species in the family Felidae and is commonly referred to as the domestic cat or house cat to distinguish it from the wild members of ...

. Humans also find these snakes in the wild and keep them for pets. They are subjected to commercial collection because of their nice skin coloration, passive nature, and small size. However, this snake is not known to survive well in captivity. Because their populations are usually isolated and small in size, this commercial collection can greatly affect the overall population. The smooth green snake population is also declining due to the use of pesticides, as well as destruction of habitats. Pesticides are particularly harmful to the snake when used in riparian areas, mountain foothills and meadows. Because the smooth green snake's diet consists mainly of insects, insecticides put the snake at great risk in areas where they are applied. The reduction of its prey is a major cause of the death of the snakes, as well as one of the most important natural threats to its population. Habitat destruction is caused by road building, logging, cattle grazing, and the draining of streams. Logging and mining conducted in a smooth green snake habitat can be a source of snake mortality. Roads and highways are a major cause of deaths, especially those near streams or other habitats the snake occupies. Livestock grazing has been found to reduce snake populations in some areas, where five times the amount of snakes were found on ungrazed areas, compared to grazed areas. The effects of livestock grazing include the reduction of grass, changes in tree species, compaction of soil, and more erosion, which affect the reptile population in these areas. Flooding, freezing, and destruction of dens can destroy large numbers of smooth green snakes, as well as other species of snake with which it may hibernate. Human recreational activities, such as off-road vehicles near wetlands, are also damaging its habitat. Lakes and streams are enjoyable areas for recreation, but human activity in these areas can degrade them. The use of off-road vehicles in or around wetlands, however, is the most damaging recreational activity.

Mud bogging Mud bogging (also known as mud racing, mud running, mud drags, or mudding) is a form of off-road motorsport popular in Canada and the United States in which the goal is to drive a vehicle through a pit of mud or a track of a set length. Winner ...

significantly damages and destroys these areas. Also, oil and gasoline from off-road vehicles has been found in snake habitats.

Conservation status

The smooth green snake is of least concern in terms of conservation, but the concern is increasing in the U.S. with some states citing anecdotal evidence of fewer sightings and residential sprawl. While there is some research showing the population of the snake is declining, only a small number of states (Iowa, Missouri,

Indiana Indiana () is a U.S. state in the Midwestern United States. It is the 38th-largest by area and the 17th-most populous of the 50 States. Its capital and largest city is Indianapolis. Indiana was admitted to the United States as the 19th s ...

Michigan Michigan () is a state in the Great Lakes region of the upper Midwestern United States. With a population of nearly 10.12 million and an area of nearly , Michigan is the 10th-largest state by population, the 11th-largest by area, and the ...

North Carolina North Carolina () is a state in the Southeastern region of the United States. The state is the 28th largest and 9th-most populous of the United States. It is bordered by Virginia to the north, the Atlantic Ocean to the east, Georgia and So ...

Montana Montana () is a state in the Mountain West division of the Western United States. It is bordered by Idaho to the west, North Dakota and South Dakota to the east, Wyoming to the south, and the Canadian provinces of Alberta, British Columbi ...

Nebraska Nebraska () is a state in the Midwestern region of the United States. It is bordered by South Dakota to the north; Iowa to the east and Missouri to the southeast, both across the Missouri River; Kansas to the south; Colorado to the southwe ...

and

) protect the smooth green snake with conservation laws. This law prohibits commercial collection of the snake and collection by individuals.

Habitat

''O. vernalis'' can be found in many different habitats, including marshes, meadows, the edges of streams, and open woods. It prefers to be on the ground, in open areas without a lot of shrubs. During hibernation, the smooth green snake looks for burrows, ant hills, and other dug-out underground areas, normally gathering in large numbers. It prefers moist habitats and areas near permanent water sources, usually staying in green areas for camouflage. Being cold blooded, it prefers warm areas, lying in the sun on rocks and logs, also using them for hiding.

Behavior

The smooth green snake relies on an environment matching its green scales for camouflage to protect itself from predators. If threatened, a smooth green snake will usually flee. It is a docile snake, seldom biting and usually allowing humans to come close. If provoked, it can secrete a substance from its anal gland, causing a foul smell. When handled by humans, it usually shows excited behavior and calms down after wrapping itself around a finger. When it hunts, it turns its head from side to side, finding prey with its tongue; the flicking of the tongue gathers air towards the snake's head, and their

Jacobson's organ The vomeronasal organ (VNO), or Jacobson's organ, is the paired auxiliary olfactory (smell) sense organ located in the soft tissue of the nasal septum, in the nasal cavity just above the roof of the mouth (the hard palate) in various tetrapods. T ...

(on the roof of its mouth) interprets the airborne pheromones and chemical signals. The green snake has no ears, relying on vibrations to figure out its surroundings. Its sight is relatively strong, at least over short distances. Due to the stretchy ligaments in its jaw, it can swallow prey whole, even those that are larger than its own body's diameter. It can shed its skin as often as every four to five weeks, allowing for new growth. During months when the weather is warmer, the smooth green snake tends to be active both day and night; in the colder, winter months, it hibernates in social groups. Ant hills and burrows of other animals are used during hibernation as part-time homes.

Diet

The smooth green snake mostly eats insects and spiders, including spineless

caterpillars Caterpillars ( ) are the larval stage of members of the order Lepidoptera (the insect order comprising butterflies and moths). As with most common names, the application of the word is arbitrary, since the larvae of sawflies (suborder Symph ...

harvestmen The Opiliones (formerly Phalangida) are an order of arachnids colloquially known as harvestmen, harvesters, harvest spiders, or daddy longlegs. , over 6,650 species of harvestmen have been discovered worldwide, although the total number of ext ...

moths Moths are a paraphyletic group of insects that includes all members of the order Lepidoptera that are not butterflies, with moths making up the vast majority of the order. There are thought to be approximately 160,000 species of moth, many of w ...

ants Ants are eusocial insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from vespoid wasp ancestors in the Cretaceous period. More than 13,800 of an estimated total of 22,00 ...

snails A snail is, in loose terms, a shelled gastropod. The name is most often applied to land snails, terrestrial pulmonate gastropod molluscs. However, the common name ''snail'' is also used for most of the members of the molluscan class Gastrop ...

worms Worms may refer to: *Worm, an invertebrate animal with a tube-like body and no limbs Places *Worms, Germany, a city **Worms (electoral district) *Worms, Nebraska, U.S. *Worms im Veltlintal, the German name for Bormio, Italy Arts and entertainme ...

, and

slugs Slug, or land slug, is a common name for any apparently shell-less terrestrial gastropod mollusc. The word ''slug'' is also often used as part of the common name of any gastropod mollusc that has no shell, a very reduced shell, or only a smal ...

. While hunting, it uses both chemical and visual clues to find prey, and kills with a strike instead of

constriction Constriction is a method used by various snake species to kill or subdue their prey. Although some species of venomous and mildly venomous snakes do use constriction to subdue their prey, most snakes which use constriction lack venom. The snake i ...

Reproduction

Sexually mature smooth green snakes mate in the late spring or summer, and gravid females lay eggs from June to September. Usually, two clutches are laid, each containing four to six eggs. Females usually lay their eggs in rodent burrows, mounds of rotting vegetation, sawdust piles, or rotting logs. In the northern habitats of this species, communal nesting has been observed. Smooth green snake eggs are white and oval; they have thin shells and are about one inch in length. They have an average mass of 2.6 grams. The eggs hatch four to 23 days after being laid.

References

Bibliography

* * * *

External links

Smooth Green Snake
Reptiles and Amphibians of Iowa.

Michigan Department of Natural Resources.
''Opheodrys vernalis''
Illinois Natural History Survey. {{Taxonbar, from=Q945692 Opheodrys Snakes of North America Reptiles of Mexico Reptiles of the United States Reptiles of Ontario Fauna of the Eastern United States Fauna of the Great Lakes region (North America) Fauna of the Great Plains Fauna of the Plains-Midwest (United States) Reptiles described in 1827 Taxa named by Richard Harlan