The smooth green snake (Opheodrys vernalis) is a species of North American nonvenomous snake in the family Colubridae. 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, 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, the United States, and northern Mexico. 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. The smooth green snake will often bob its head 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. 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 coloration is different from that when it matures.

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Subspecies

  • Eastern smooth green snake, Opheodrys vernalis vernalis <small>(Harlan, 1827)</small>
  • Western smooth green snake, Opheodrys vernalis blanchardi <small>Grobman, 1941</small>
  • Northern smooth green snake, Opheodrys vernalis borealis <small>Grobman, 1992</small>

Nota bene: A trinomial authority in parentheses indicates that the subspecies was originally described in a genus other than Opheodrys.

Etymology

The subspecific name, blanchardi, is in honor of American herpetologist Frank N. Blanchard.

Geographic range

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The smooth green snake is native to the Nearctic region. The range spreads through southeastern Canada, west to Saskatchewan, and south through Illinois and Virginia. It can also be found in other areas, such as in Wyoming, Colorado, New Mexico, Iowa, Missouri, Texas, and Northern Mexico.

Threats

O. vernalis is hunted by various predators, including the red-tailed hawk, great blue heron, rough-legged buzzard, bears, raccoons, foxes, and the common house cat. Humans often find these snakes in the wild and keep them as pets. It is subjected to commercial collection because of its attractive skin coloration, passive nature, and small size. However, this snake is not known to survive well in captivity. Because its populations are usually isolated and small in size, this commercial collection can greatly affect the overall population. 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. 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, Michigan, North Carolina, Montana, Wyoming, Nebraska, Colorado and Texas) 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. Being cold blooded, it prefers warm areas, lying in the sun on rocks and logs, also using them for hiding. 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 near the snake's head, and the Jacobson's organ (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 prey that is larger than its own body diameter. It can shed its skin as often as every four to five weeks, allowing for new growth. In the northern habitats of this species, communal nesting has been observed.