The northern rough greensnake is a slender, light green snake that lives among the branches of trees and shrubs. The upperside color is plain light green; the belly is yellow or cream colored and devoid of any markings. The scales along the back and sides are weakly keeled, making it feel rough to the touch. The anal plate (the last belly scale, which covers the anal opening) is divided. This snake has an elongated body and a long, slender tail, allowing its body weight to be evenly spread across the branches and leaves of trees and bushes.
Hatchling rough greensnakes are olive drab on the back and have a white belly. Their color changes to bright green after they shed the first time, within a week after hatching.
Dead rough greensnakes will lose the yellow pigmentation within their skin and turn a blue color within several hours of death.
Rough greensnakes are considered a gentle and harmless species. When first captured, a specimen may gape open its mouth and reveal a purplish-black lining, but this is a bluff, and most specimens will not try to bite. Some newly captured specimens, as a form of defense, will produce a musk from glands at the base of their tail that may be mixed with feces.
Similar species: The smooth greensnake (O. vernalis) used to live in the northern parts of our state, but it has not been seen in Missouri since 1970. A Missouri species of conservation concern, it is considered extirpated from our state. The easiest way to tell the two greensnakes apart is by touch: The scales on the back of a rough greensnake feel rough; those on the back of a smooth greensnake feel smooth. The smooth greensnake also lives in different regions and habitats: it is a grassland (not a woodland) species and, in Missouri, it would be expected to occur only in the northern half of the state, most likely as relict populations in our extreme northern counties (not in the Ozarks).
Adult length: 22 to 32 inches; occasionally to 46 inches. The tail may account for up to nearly half of total length. Adult females are larger than adult males; males have a longer tail than females.
In Missouri, occurs throughout the southern two-thirds of the state and along the Mississippi River Hills in northeastern Missouri.
Habitat and Conservation
This arboreal (tree-living) species resides in the dense trees and shrubs that grow along creeks, rivers, ponds, reservoirs, and forest edges. They spend most of their time resting among branches between about 3 to 13 feet above the ground.
This species has not been well studied in Missouri. Studies in Arkansas showed that rough greensnakes were almost always found within about 10 feet of a pond, creek, or other body of water, but observations in North Carolina indicated that a majority of individuals in that part of the species' range live on the ground. In Missouri, rough greensnakes appear to live in a variety of brushy, viny, wooded riparian habitats as well as rocky, forested hillsides, river bluffs, and even sometimes under flat rocks.
The active season of this species is late March through October, with peak activity in spring (April and May) and autumn (September and October).
The rough greensnake is diurnal and spends most of its time among the branches and leaves of trees and bushes. It remains motionless among leaves and branches and relies on its coloration to remain undetected. If a slight wind moves the branches, the greensnake will bend and wave in along with the foliage.
This species becomes active soon after sunrise in the morning, and individuals will select a site to spend the night from one-half to one hour before sunset. At night, these snakes coil among the leaves near the tip of branches.
Rough greensnakes may be observed crossing roads, trails, and creeks during the active season. Individuals are often seen crossing the former railroad bed of Katy Trail State Park; most of these snakes are migrating from the Missouri River floodplain into the adjacent upland, rocky, wooded hillsides.
Rough greensnakes are capable swimmers and have been observed swimming across an Ozark stream on several occasions.
Overwinter dormancy takes place in deep leaf litter, inside rotten logs and stumps, and in the ground at a depth of more than 8 inches.
Food
The diet of rough greensnakes is predominantly insects and spiders. More specifically, their prey mostly includes spiders, hairless caterpillars, grasshoppers, crickets, beetles, dragonflies, and damselflies . Rough greensnakes also may eat young treefrogs, land snails, praying mantids, wood roaches, katydids, and walking sticks.
Slender, arboreal, and insectivorous snakes like this species must eat more prey and eat more often to sustain themselves and reproduce, compared to snakes that eat vertebrate prey.
Status
Missouri populations are considered secure.
Life Cycle
Mating occurs in the spring and sometimes during autumn. Egg laying occurs in June and July, about 35 days after mating. Pregnant females leave the safety of trees to find nesting spots in deep leaf litter, under brush piles, behind the loose bark of a standing dead tree, or in or rotten logs or stumps. The female produces 1–14 eggs, with an average of 6. Larger females produce more eggs than smaller females. There is only 1 clutch per year. Incubation usually lasts up to about 2 months (22–91 days), with most clutches hatching in August and September.
Male rough greensnakes are reproductively mature at the age of 1 year, and females are mature at age 2 or 3. They may survive to age 8 in the wild.
Human Connections
One of Missouri's most attractive snakes, it is also harmless to people.
Animals that eat insects can be harmed indirectly by pesticides. This is apparently one of the reasons why the similar-looking smooth greensnake of northern Missouri disappeared from our state. So far, the rough greensnake seems to have been spared that fate, but it is especially vulnerable to insecticide contamination.
Rough greensnakes have been found dead on Missouri’s roads and highways during their active season.
The genus name, Opheodrys, is from Greek roots and means "tree snake." The species name, aestivus, is from the Latin word for "summer."
Ecosystem Connections
This slender snake eats mainly insects and spiders, and they help to check the populations of many caterpillars that feed on the leaves of trees.
Predators of this species include hawks, blue jays, kingsnakes, and domestic cats. A 1990 study in Arkansas found that pregnant females of this species are often preyed upon by speckled kingsnakes and southern black racers. Another Arkansas report noted that a rough greensnake had been eaten by an eastern coachwhip.
Rough greensnakes have an interesting internal adaptation that protects them from exposure to ultraviolet radiation. Because they are diurnal and arboreal, a great deal of time is spent in direct sunlight. Their internal organs — especially their reproductive organs — must be protected from the sun’s dangerous ultraviolet radiation. This species, and several arboreal snakes in other parts of the world, have evolved a black peritoneum. This black envelope covers their internal organs and provides a shield to prevent damage from ultraviolet radiation. It is unlikely that many other snakes in Missouri have this adaptation. A study of worldwide genetic relationships of snakes in the family Colubridae found that the North American rough greensnake originated from arboreal snakes found in tropical East Asia.
