Geographic Range
Opheodrys aestivus
, commonly known as the rough green snake, is found widely throughout the southeastern
United States. It is found frequently as far north as southern New Jersey and can
be found along the East Coast into the Florida Keys. The western range stretches to
central Oklahoma, Texas, and into northern Mexico.
Habitat
Rough green snakes are typically found on forest edges near ponds or lakes. Although
they are arboreal snakes, they forage in dense vegetation along pond and lake shorelines
during the day. Their nights are spent coiled in the branches of trees. Rough green
snakes choose perches based on distance from shorelines, height in branches, and thickness
of the branch.
Rough green snakes are most commonly found in deciduous trees, shrubs, hedgerows,
and fields.
- Habitat Regions
- temperate
- terrestrial
- Other Habitat Features
- riparian
Physical Description
Rough green snakes are small and thin. The dorsal and lateral surfaces are a uniform
green, the underbelly, chin and labial scales range from yellowish-green to cream.
Males and females have no differences in color or pattern, but females are larger
in length and mass, while males have a longer tail length. Juvenile rough green snakes
look like smaller adults, except they are lighter in color.
Since these snakes are diurnal and tend not to avoid the heat of the day, their peritoneum
is black and dense. This is believed to be an adaptation that acts as an ultraviolet
radiation shield, keeping these snakes from becoming too hot. Females range from 11
to 54 g in mass, with an average of 26.7 g, males are from 9 to 27 g, with an average
of 16.3 g. Average lengths are 947 mm in females and 892 mm in males.
- Other Physical Features
- heterothermic
- Sexual Dimorphism
- sexes alike
- female larger
Development
When compared to other snakes,
Opheodrys aestivus
embryos are well-developed upon egg laying. This allows for a short incubation period
outside of the female, thus shortening the span for predators to eat the defenseless
eggs. These eggs usually range from 21.4 to 33.6 mm long, 9.3 to 11.1 mm wide, and
1.2 to 2.4 g. Upon hatching, their length averages 128 to 132 mm and weigh 1.1 g
(Mitchell, 1994). Most growth occurs in the first year of life. Females grow at a
faster pace and reach larger sizes than males. According to Plummer (1985), the growth
of rough green snakes follows the Von Bertalanffy model, which allows any size snake
to be aged relatively accurately. However, this model is more accurate for younger
snakes; error is positively correlated with age.
Reproduction
Rough green snakes reproduce sexually with internal fertilization. These snakes are
promiscuous, with males leaving almost immediately after copulation (Richmond, 1956).
Courtship behavior of rough green snakes consists of visual orientation of males towards
females, approach, body contact, and body alignment. Some motor patterns that are
displayed during these stages are dorsal crawling, chin rubbing, tail waving, and
head jerking. Once aligned with a female, a male begins with tail search copulatory
attempts in energetic spurts followed by periods of motionlessness. On average, alignment
is accomplished in about 2:45 minutes and the copulatory sequences average about 16:04
minutes (Goldsmith, 1988).
- Mating System
- polygynandrous (promiscuous)
Rough green snakes reach sexual maturity at 21 months in males and 21 to 33 months
in females (Plummer, 1985). Although they breed every spring, fall matings have been
noted (Mitchell, 1994). The gestation period can range from 5 to 12 weeks, depending
on temperatures, and they typically lay their eggs during June and July (Plummer,
1990). Clutch size is 3 to 12 soft-shelled eggs (Mitchell, 1994). Males first breed
in the spring of their second year, usually around 21 months. However only half of
females participate in breeding during their second spring, while the other half delays
an additional 12 months.
Reproductively mature females can range from 360 to 400 mm snout-vent length, while
sexually-mature males average 300 mm (Plummer, 1985).
- Key Reproductive Features
- iteroparous
- seasonal breeding
- sexual
- oviparous
Female rough green snakes nearing oviposition leave their usual arboreal habitat to
travel on the ground away from the shoreline. They seek out hollows in dead or living
trees, decaying logs, under rocks or under boards in sandy soil. Such areas provide
sufficient moisture levels for egg-laying. These locations are usually about 30.0
m (+/- 9.0 m) away from the shoreline. After oviposition, females return to the shoreline
and resume her arboreal post. Females have no further contact with their eggs after
hatching (Plummer, 1990).
- Parental Investment
- no parental involvement
-
pre-fertilization
-
protecting
- female
-
protecting
-
pre-hatching/birth
-
provisioning
- female
-
protecting
- female
-
provisioning
Lifespan/Longevity
Survival rates are not well known for juvenile rough green snakes. However, adults
have low survivorship, which may partly explain why these snakes become sexually mature
early and lay rather large clutches annually. The main causes of mortality are environmental
factors (hot, dry conditions) and predation. This species has an average life expectancy
of 5 years, but they can reach up to 8 years.
Behavior
Rough green snakes are arboreal and diurnal. They spend their nights coiled on the
far ends of tree branches near the shoreline (Plummer, 1997). Although arboreal, they
spend time on the ground foraging. They are sedentary and will not bite as a defense,
but rather flee into dense vegetation where they are camouflaged (Mitchell, 1994).
Rough green snakes are active except in the cold winter months, usually December to
February, depending on geographic location and temperature (Mitchell, 1994). The cold
months are spent in hibernation. Rough green snakes are solitary, but there is a possibility
that they use communal egg-laying (Palmer & Braswell, 1976).
- Key Behaviors
- arboreal
- diurnal
- sedentary
- hibernation
- solitary
Home Range
Rough green snakes have a home range of roughly 67 m in shore length, while only straying
about 3 m away from the shore itself. Home ranges vary year to year by about 50 m
(Plummer, 1997). They are not territorial.
Communication and Perception
Rough green snakes use their tongue to sense chemical cues. They also have keen eyesight,
allowing them to easily spot movement of prey. Mating behaviors involve tactile and
visual cues.
- Communication Channels
- chemical
- Perception Channels
- visual
- tactile
- vibrations
- chemical
Food Habits
Rough green snakes are insectivores, consuming crickets, grasshoppers, other insects,
and spiders (Mitchell, 1994). They exclusively use their extraordinary vision to hunt
live prey. Even a slight movement of a leg or antennae is sufficient to draw the attention
of these snakes to the location of their prey (Goldsmith, 1986). According to Goldsmith
(1986), during the initial phase of their approach, these snakes use fast and irregular
movements, but they slow down as they further approach their prey. When rough green
snakes are about 3 cm from prey, they assume spring-like curves with their body, followed
by a straightening of the body, allowing the snake to propel its head toward the prey,
striking either at the head or thorax. Rough green snakes sometimes raise their head
above the substrate immediately upon striking in order to get prey away from anything
that may aid their escape. Prey is worked further into the mouth and swallowed by
movements of the jaw. Prey is usually swallowed head first.
- Primary Diet
- carnivore
- Animal Foods
- insects
- terrestrial non-insect arthropods
Predation
Many animals prey up on these snakes, including larger snakes, birds, domestic cats,
and even some spiders (Plummer, 1990; Mitchell, 1994). Their only defense mechanism
is camouflage.
- Anti-predator Adaptations
- cryptic
Ecosystem Roles
Rough green snakes are a source of prey for larger snakes, birds, and other small
predators.
There are a few known parasites that affect rough green snakes. They are infected
occasionally with
Cryptosporidium
species, which affects the gastrointestinal tract, causing epithelial necrosis.
- Cryptosporidium species
Economic Importance for Humans: Positive
Although not common pets, domestication of these snakes has become increasingly popular
because they are easy to care for.
- Positive Impacts
- pet trade
Economic Importance for Humans: Negative
There are no known adverse effects of Opheodrys aestivus on humans.
Conservation Status
Rough green snakes are listed as a species of least concern. Due to their apparent
population stability, no conservation efforts are planned.
Additional Links
Contributors
Kaelin Creange (author), Radford University, Karen Powers (editor), Radford University, Tanya Dewey (editor), University of Michigan-Ann Arbor.
- Nearctic
-
living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- temperate
-
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
- terrestrial
-
Living on the ground.
- riparian
-
Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).
- heterothermic
-
having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.
- polygynandrous
-
the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.
- iteroparous
-
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
- seasonal breeding
-
breeding is confined to a particular season
- sexual
-
reproduction that includes combining the genetic contribution of two individuals, a male and a female
- oviparous
-
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
- arboreal
-
Referring to an animal that lives in trees; tree-climbing.
- diurnal
-
- active during the day, 2. lasting for one day.
- sedentary
-
remains in the same area
- hibernation
-
the state that some animals enter during winter in which normal physiological processes are significantly reduced, thus lowering the animal's energy requirements. The act or condition of passing winter in a torpid or resting state, typically involving the abandonment of homoiothermy in mammals.
- solitary
-
lives alone
- chemical
-
uses smells or other chemicals to communicate
- visual
-
uses sight to communicate
- tactile
-
uses touch to communicate
- vibrations
-
movements of a hard surface that are produced by animals as signals to others
- chemical
-
uses smells or other chemicals to communicate
- cryptic
-
having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.
- pet trade
-
the business of buying and selling animals for people to keep in their homes as pets.
- carnivore
-
an animal that mainly eats meat
- insectivore
-
An animal that eats mainly insects or spiders.
References
Brower, A., M. Cranfield. 2001. Cryptosporidium sp.-Associated Enteritis without Gastritis in Rough Green Snakes. Journal of Zoo and Wildlife Medicine , Vol. 32, No. 1: 101-105.
Cooper, W. 2007. Elevated tongue-flicking rate to cricket surface chemicals by the arthropodivorous rough green snake Opheodrys aestivus. AMPHIBIA-REPTILIA , Volume: 28 Issue: 3: 413-417.
Goldsmith, S. 1988. Courtship Behavior of the Rough Green Snake, Opheodrys aestivus (Colubridae: Serpentes). The Southwestern Naturalist , Vol. 33, No. 4: 473-477.
Goldsmith, S. 1984. Aspects of the Natural History of the Rough Green Snake, Opheodrys aestivus (Colubridae). The Southwestern Naturalist , Vol. 29, No. 4: 445-452.
Goldsmith, S. 1986. Feeding Behavior of an Arboreal, Insectivorous Snake (Opheodrys aestivus) (Colubridae). The Southwestern Naturalist , Vol. 31, No. 2: 246-249.
Gray, B. 2005. The Serpent's Cast - A Guide to the Identification of Shed Skins from Snakes of the Northeast and Mid-Atlantic States . Lansing, Michigan: ECO Herpetological Publishing & Distribution.
Mitchell, J. 1994. The Reptiles of Virginia . Washington and London: Smithsonian Institution Press.
Palmer, W., A. Braswell. 1976. Communal Egg Laying and Hatchlings of the Rough Green Snake, Opheodrys aestivus. Journal of Herpetology , Vol. 10, No. 3: 257-259.
Plummer, M. 1990. Nesting Movements, Nesting Behavior, and Nest Sites of Green Snakes (Opheodrys aestivus) Revealed by Radiotelemetry. Herpetologica , Vol. 46, No. 2: 190-195.
Plummer, M., H. Snell. 1988. Nest Site Selection and Water Relations of Eggs in the Snake, Opheodrys aestivus. Copeia , Vol. 1988, No. 1: 58-64.
Plummer, M. 1983. Annual Variation in Stored Lipids and Reproduction in Green Snakes (Opheodrys aestivus). Copeia , Vol. 1983, No. 3: 741-745.
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Plummer, M. 1985. Growth and Maturity in Green Snakes (Opheodrys aestivus). Herpetoligica , 41: 28-33.
Plummer, M. 1981. Habitat Utilization, Diet and Movements of a Temperate Arboreal Snake (Opheodrys aestivus). Journal of Herpetology , Vol. 15, No. 4: 425-432.
Plummer, M. 1990. High Predation on Green Snakes, Opheodrys aestivus. Journal of Herpetology , Vol. 24, No. 3: 327-328.
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Plummer, M. 1997. Speed and Endurance of Gravid and Nongravid Green Snakes, Opheodrys aestivus. Copeia , Vol. 1997, No. 1: 191-194.
Plummer, M. 1993. Thermal Ecology of Arboreal Green Snakes (Opheodrys aestivus). Journal of Herpetology , Vol. 27, No. 3: 254-260.
Richmond, N. 1956. Autumn Mating of the Rough Green Snake. Herpetologica , Vol. 12, No. 4: 325.
Richmond, N. 1952. Opheodrys aestivus in Aquatic Habitats in Virginia. Herpetologica , Vol. 8, No. 2: 38.
Tinkle, D. 1960. A Population of Opheodrys aestivus (Reptilia: Squamata). Copeia , Vol. 1960, No. 1: 29-34.