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Scientific name: Clemmys insculpta
Common name: 
American Wood Turtle

(Information in this Species Page was compiled by Amber Bucinski in Biology 220W, Spring 2002, at Penn State New Kensington)

Clemmys insculpta (the American wood turtle) is a moderately sized (6 to 10 inch long upper shell, or "carapace"), semi-aquatic turtle that is found in deciduous woodland streams, wet meadows, and farmland habitats of roughly the northeastern quarter of the United States up into southern Ontario, Quebec, and Nova Scotia. The wood turtle is under intense ecological pressure due to the widespread degradation and destruction of its riparian habitats by forestry, agriculture, residential development, and stream channelization and modification for flood control and fisheries development. Further, direct human predation, pet collection, and the impact of many human-subsidized predators (raccoons, skunks, dogs, etc) have significantly depressed the population densities of this species.

The key aspect of the wood turtle’s preferred habitat is water: especially streams and rivers that run through wooded areas. There are three specific sub-habitat components that are critical for C. insculpta:

  • hard bottomed streams or rivers
  • herbaceous vegetation for foraging
  • sandy substrate (sandbars, sand spits, beaches etc) for nesting

A diverse mosaic of standing forest (either coniferous or deciduous), grassy or herbaceous sun gaps, berry thickets, and wet meadows or marshland around a clear, moderately fast running stream is ideal for this species. Most wood turtles spend much of their lives in or near their streams, although females tend to be more terrestrial than males.

The carapace of C. insculpta is low and typically has a keel (“raised ridge”) down the center of the shell. The wood-like appearance of the shell’s ringed scales is often given as an explanation for the species’ common name (the other explanation being, of course, its preferred habitat). The carapace is brown to gray-brown often with radiating lines of yellow and black down the ridges. The underside shell, or "plastron" has no hinge (see the Eastern Box Turtle species page for a description of shell hinges), is yellow in color with darkened areas along the outer edge, and a V-shaped notch at the base of the tail.

The head of the wood turtle is black often with lighter dots or markings. The skin of the throat, lower neck, and under-surfaces of the legs may be yellow, red-orange, and/or pinkish-red. These skin areas may also have darker, often freckle-like spots. The upper surfaces of the legs are black to dark brown. Regional populations of C. inscuplta may display particular coloration patterns. In the eastern portion of the species’ geographic range, individuals have orange to reddish colored skin, while individuals in the west tend to have yellow to yellow-orange colorations. Adult males have wider heads than females and more elongated, even domed carapaces. Male plastrons are concaved (depressed) in the center while female plastrons are flat. The tails of the adult male are thicker and longer than females. Male cloacal openings also extend beyond the edge of the carapace when the tail is extended while this “vent” opening in the female is under the edge of the carapace even when the tail is extended.

Diet and Activity
The wood turtle is an omnivorous, opportunistic feeder. It feeds in or out of water and consumes leaves, flowers, and fruit of a wide range of herbaceous and woody plants (including violets, strawberries, willows, raspberries, and dandelions). They will also eat fungi, grasses, snails, slugs, insects, earthworms, eggs, and carrion. In spite of their slow and deliberate habits they also are able to eat young rodents. Behaviors associated with earthworm hunting (“earthworm stomping”) by this species have been extensively described. The turtle extends one foreleg, raises the front of its body, and then releases its support causing the front of the plastron to crash onto the soil surface. This behavior is repeated in regular patterns that may go on for thirty minutes or more. The ground vibrations are thought to draw earthworms to the soil surface where the turtle readily consumes them.

The wood turtle is diurnal but is especially active in the morning and evening. It spends a great deal of its day basking near its stream and is described as a good “cold weather” turtle that is quite efficient in heating itself in the sun and avoiding excessive heat loss. Its active season runs from April until October. Each turtle tends to stay in a home range of two to fifteen acres although some individuals may travel in their streams for considerable distances. Hibernation occurs either under water (at depths of three feet or so), in muddy burrows, in rests under logs or roots, in pools, in muskrat nests or beaver lodges, or even along the stream bank under the forming ice.

Mating and Reproduction
Both male and female wood turtles display aggressive dominance behaviors toward members of the same sex and aggressive mating behaviors toward members of the opposite sex. Actual mating may occur on land or in the water. Mating may occur anytime during the active season but is more likely in the spring than in the fall. Females make their nests primarily in early June through late July. A sandy, moderately sloping, non-vegetated site, near a stream, three or so feet above the water line are ideal nesting sites. Particularly optimal sites may be used by a specific female year after year. The nest chamber is four inches wide and at least three inches deep. Clutch sizes range from five to fifteen eggs with ten being average. After laying the eggs, the female covers and obscures the nest and then leaves. Most eggs do not hatch. Nearly eighty percent of wood turtle eggs are consumed by raccoons and much of the remaining twenty percent by other nest predators (like shrews, skunks, and foxes). Incubation of the unconsumed eggs takes 47 to 69 days depending on the temperature and moisture conditions of the nest site. The eggs hatch in September and the young turtles (1 to 1 ½ inches in length, circular carapaces, dark brown color) seek aquatic habitats where they survive almost exclusively as predators. Wood turtles reach sexual maturity between 14 and 20 years of age and may live up to 50 years even in the wild (a captive wood turtle lived to 58 years of age).

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