Description and Identification

Graptemys pseudogeographica kohnii is a medium to large map turtle. Females will typically reach 8-10”(20.3-25.4cm), max 10.6” (27cm), while males stay smaller at 3.5-5.5” (8.9-14cm), max 5.9” (15cm). The carapace is olive to brown with yellow, oval-shaped markings and a dark blotch on each pleural scute. It has a defined, but low keel and its posterior edge is serrated. Small vertebral spines are noticeable in hatchlings and juveniles, but almost completely disappear in adult females. The plastron is cream to yellow with an extensive seam following pattern that slowly vanishes with age. The skin of the head, neck, legs, and tail is olive to dark olive with yellow markings. The post-orbital mark is a stripe from the neck that extends toward the orbit and bends completely around the eye forming a crescent. This crescent may be broken as it travels below the eye. This crescent, the white eyes without a transverse bar, and a white beak identify G. p. kohnii from the other subspecies, G. p. pseudogeographica. Males will have longer and wider tails with the cloacal opening 1/2 to 2/3rds of the way down the tail and a more juvenile appearance. Females will have shorter, narrower tails, a much larger build, and broader heads, though not to the extent of the broad-head group of Graptemys species.

Distribution

The Mississippi Map Turtle is found in the lower Mississippi River watershed. It ranges from western Tennessee west through central Missouri to southeastern Nebraska then south through Arkansas, Louisiana, eastern Kansas, Oklahoma and Texas, and western Mississippi. It may also be found in the Pearl River of Mississippi and Louisiana.

Native Habitat

G. pseudogeographica ssp. primarily occupies large rivers and their backwaters, but will live in lakes, ponds, and more. Plentiful aquatic vegetation seems to be a preference in habitat characteristics, as are slower currents and a multitude of basking locations. At least in Wisconsin, a muck bottom is favored. In Kentucky, there was a wide selection of habitats used by the Mississippi Map Turtle.

Wild Diet

The Mississippi Map turtle is generally omnivorous. Prey species include: freshwater sponges; bryozoans; clams; snails; crayfish; spiders; insects and their larvae; fish; algae; carrion; and assorted seeds, fruits, and leaves of plants. Adult females in the southern end of the range have a primary diet of mollusks.

Behavior

Due to G. ouachitensis ssp. having been previously listed under G. pseudogeographica, much of the behavioral history is partially masked between G. ouachitensis ssp. and G. pseudogeographica ssp. These species are active from late March to mid-October, with shorter active periods in the north and longer active periods in the south. They have a tendency to hibernate in groups. Winterkill has been documented during dry winters in some locations within the range. These species, including juveniles, spend a large portion of their day basking. Selected basking locations are seldom on or near shore and can be as high as 2m above the water surface. While basking, these species are wary and difficult to approach; one turtle re-entering the water due to disturbance often leads others to follow.

Reproduction

Males are sexually mature at a minimum PL of approximately 3" (7.5cm), which they typically reach by the time they are 4-6 years old in the wild. Females mature at a PL around 7.1" (18cm), which may require as many as 8-10 years to reach. Captive specimens tend to grow and mature more quickly due to a nearly year-round growing season.