The female of this species attains a carapace length of about 10 inches, while the male seldom exceeds five inches. The Map Turtle’s name is derived from the network of fine yellow lines that crisscross the carapace and vaguely resemble the contour lines on a topographic map. These lines are very noticeable on young specimens but they fade with age. Map Turtles are extremely wary and show a marked preference for sizable bodies of deep water, such as large rivers and lakes, where they can dive to the safety of the depths. The broad, flat crushing surfaces of the powerful jaws are well suited for consuming snails, crayfish, and clams, which form the bulk of the diet. Map Turtles may be active year-round, and have even been observed walking around under the ice. LENGTH: Males - 3.5”–6.25”; Females - 7”–10.75” .
Text courtesy of the Ohio Division of Wildlife: https://wildlife.ohiodnr.gov/portals/wildlife/pdfs/publications/id%20guides/pub354_Reptiles-opt.pdf