Identification
Named for their appearance, Common Map Turtles possess a pattern on their carapace
that resembles an intricate map of waterways. The pattern consists of yellowish
or orangish lines with dark boarders. While the pattern is generally very prominent,
it may be dark and faded on adults. The upper surface of the carapace also features
low, rolling vertebral keels. In juveniles the keels are more prominent. The
head, neck and limbs are dark olive, brown or black in coloration and are highlighted
with thin yellow, green or orangish stripes. Behind the eye there is often a
small oval or triangular light spot. Adult female Common Map Turtles are larger
than males and have a broader head. Males, in contrast, possess longer tails.
Distribution and Status
Common Map Turtles are distributed across much of the Midwest from the northern
portion of Michigan’s lower peninsula, east to northwestern Vermont through
southern Ontario, west to central Minnesota and south to southern Arkansas and
southwestern Georgia. Isolated populations also survive in Pennsylvania, northwest
New Jersey, and southern New York. In the Midwest, the species survives in all
eight states. (US
distribution map; Midwest
distribution map)
Ecology
Optimum habitat for the Map Turtle includes large creeks with slow to moderate
currents, complete with pools and riffles, a soft to gravel bottom, and aquatic
vegetation. Map Turtles are also found in lakes, rivers, reservoirs, sloughs,
marshes and bays. Feeding only occurs while they are in the water, but they
are often observed basking in large groups on logs
Threats and Management Issues
Population declines have occurred as a result of the pollution of waterways
and also from damage or destruction to suitable nesting sites. In lakes, Map
Turtles can be injured or killed by boat propellers, and fish hooks. Unfortunately,
turtles are also sometimes used as targets for firearms whilst basking.
Resources
Ernst. C. H., J. E. Lovich and R. W. Barbour. 1994. Turtles of the United States and Canada. Smithsonian Institution Press, USA.
General reference guides and websites.
Bruce Kingsbury, Director
Center for Reptile and Amphibian Conservation and Management
Science Building
Indiana-Purdue University
2101 East Coliseum Blvd.
Fort Wayne, IN 46805-1499