Wood Turtle (Clemmys insculpta)

Legal Status in U.S.: Unprotected Legal Status in Wisconsin: Threatened Length: 6-8 inches

For information on Wisconsin's turtles and lizards including an identification key and more, order your copy of Turtles & Lizards of Wisconsin.

Description

The name "wood" suits this medium-sized turtle. Each roundish segment of its six to eight-inch shell looks like a woodgrained cross-section of a branch, complete with growth rings and yellow rays radiating from protruding blackflecked centers. Its brownish, sculptured shell is a fusion of chiseled pyramids, hence its species name "insculpta."

When the shell is dry, the grooves take on a spider web pattern. A noticeable midrib or keel runs front to back. The bottom shell is yellow with each segment blotched black along its side. On males, the lower shell is concave for mating. A black, blunt head and brown limbs are highlighted red or yellow on throat and soft connecting flesh. Males have long, thick tails with the cloacal opening, or anus, located outside the shell's edge. Females have slighter tails with the cloacae opening within shell boundaries.

Habits

The wood turtle is also well-named because of its choice of habitat, but its genus, Clemmys, is known as the "pond turtles" group. Putting these together means the wood turtle is semi-aquatic, living along forested rivers and streams. Water pollution, irrigation, and forest erosion have tainted many of its former haunts.

Active by day, April to November, wood turtles are omnivorous and consume insects, mussels, carrion, berries, dandelions and other succulent herbs.

In late fall, wood turtles inhabit stream banks and hibernate over winter in large community burrows.

Distribution

Wood turtles were once found throughout the state, except in the southwestern-most portion. Today, small scattered populations exist in isolated habitat. This turtle's original North American range extended from Nova Scotia to eastern Minnesota, south to northeastern Iowa, east to Virginia and north to New York. It is now threatened or endangered in much of this range.

In Wisconsin, wood turtles live mainly in and along moderate to fast flowing streams and rivers. When summer arrives, they forage in deciduous forests and open meadows adjacent to these rivers. Turtle experts now believe that wood turtles may be less terrestrial than originally believed; some "woodys" may inhabit rivers year round.

Breeding Biology

Like ornate box turtles, wood turtles mature late and live as long as 58 years. They mate in spring and fall, in or out of water. Females dig nests in June on communal gravel sites along banks or railroad beds. Wood turtles have been seen nesting along the Elroy-Sparta bike trail, formerly a railroad right-of-way.

But the nests don't always survive. Egg predation by skunks, raccoons and opossums is becoming a serious problem due to an increase in the number of these scavengers since human settlement.

If the nest makes it through, a clutch of 4 to 17 white, smooth eggs laid in June will hatch in September. Gray hatchlings look awkward with tiny bodies and oversized tails.

Current Status

Before wood turtles were placed on Wisconsin's endangered species list in 1974, hundreds were taken from the wild each fall and sold to biological supply houses. One collector recalls taking over 100 from one stream bank in 1972. Today, no wood turtles are found there. Collecting for biological experiments and dissection may also be threatening other Wisconsin reptiles and amphibians, as well as many of the world's primates. Commercial overharvesting did in the now extinct passenger pigeon; no one ever thought we'd run out.

Collecting wood turtles for pets is another problem. The alert wood turtle is as quick as a rat in mastering a maze and it learns to become a responsive pet. But captive turtles are usually not given proper space and substrate to breed. This means lost wild wood turtles in the future. Highway deaths take an uncounted number of "woodys." One stretch of road in northeastern Wisconsin often frequented by wood turtles is marked with a "turtle x-ing" sign. Not uncommonly, well-intentioned people find a turtle near the side of the road, think it lost and take it home. Instead, they should try to guess which side of the road the turtle wants to be on and set it down well away from the road. Watch out for flailing claws!

Excerpt from THE ENDANGERED AND THREATENED VERTEBRATE SPECIES OF WISCONSIN

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Status: State Threatened (1975).

Occurrence: Found primarily in the north and western two thirds half of Wisconsin.

Aid to ID: Medium sized semi-terrestrial turtle. The dull brown carapace (upper shell) is very rough; each section of the shell is composed of concentric ridges (growth rings) that form an irregular pyramid. Plastron (bottom shell) yellow with black blotches. Black head and dark brown extremities. Yellow to burnt orange skin on neck and in leg sockets.

Habitat: Prefer lowland hardwood forests and open wet meadows associated with moderate to fast current streams and rivers with sand or gravel substrates. May forage in upland deciduous mesic forest and open meadows in summer. Use south facing sandy river banks or flat sandy soil openings adjacent to rivers for nesting sites, including gravel banks, roadsides, fields, and meadows. Hatchling and juveniles prefer alder thickets associated with shorelines and are considered critical habitat for this segment of the population.

Food Habits: Omnivorous. Diet includes: insects, mollusks, carrion, worms, blackberries, dandelions, mullen, sorrel, strawberries, grasses, sedges, filamentous algae, and mushrooms.

Natural History:

Active: March to November. Active diurnally, especially in the morning. Solitary in late spring and summer when mostly terrestrial. Return to river in September and October. May aggregate in or near hibernation sites. Does not estivate.
Hibernation: In banks or bottoms of streams and rivers in winter.
Reproduction: Breed from March to November, but usually March to April and October to November. Reproductive activity (eg. courtship, copulation) is aquatic. Lay clutches of 4 to 18 eggs (avg. 8) in late May or June. Incubation approximately 70 days. Eggs hatch August to September. Sexual maturity reached in 10-14 years. This species is a communal nester and females from several miles of stream may congregate in a discrete, traditional site each year to nest, especially where nesting sites are scarce.

Management Considerations: Threats include heavy bank erosion, increased small mammal populations (nest predators), water pollution, and vehicular traffic. Use of riprap on river banks may preclude access to nesting sites, and plantings in sandy soil openings and on river banks may destroy nesting sites by shading them out. Populations formerly reduced due to widespread collection by biological supply houses and the pet trade. Poaching still occurs with this species. Wood turtles have a strong association with clear water and may benefit from watershed management aimed at reducing erosion and sedimentation. This species is vulnerable to very heavy nest predation because of communal nesting behavior. Predation exclusions may prove successful in recovering this species. Electrical fencing has been somewhat effective when properly set up.

Stream bank brushing, especially when done along both shorelines and over long distances, strongly disfavors this species, especially the younger age classes.

Information compiled from publications ER-513 89REV and ER-091.

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