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The Missouri River is an extremely important river system in South Dakota. At one time, the mighty "MO" flowed naturally through the center of South Dakota’s grasslands. Now, several large dams control the water flow, drastically changing the ecology of the Missouri River and its floodplain. As a result, many South Dakota river-associated species are affected. Floodplain vegetation is disappearing and aquatic animals are losing important nesting and denning areas. One particular South Dakota resident species affected by the ever-changing Missouri River is the false map turtle (Graptemys pseudographica).

Generally, map turtles occur within the United States. Although map turtles may look like painted turtles, such as the western painted turtle—a common turtle in South Dakota, their shell pattern has a map-like appearance, leading to the name "map" turtle. False map turtles, as the name implies, have indistinct shell patterning unlike true map turtles. The false map turtle’s shell patterning appears as a vague net-like outline across the back with faint yellow markings in the background. This patterning gives the false map turtle an outstandingly beautiful outer shell.

The false map turtle has a moderately sized olive to brown carapace (back) with a saw-tooth edge along the center of the back and rear border. False map turtles are also known as "sawback" turtles because their saw-tooth edges resemble the teeth of a saw blade. Dark spots are scattered rather evenly, with one spot per scute (external bony plate), across the back and hind rim of the carapace. False map turtles have yellow plastrons (bellies) with dark lines around the edges and within the seams. As false map turtles age, the well developed designs fade and the edges of the shell dull. Distinct yellow lines cover the head, neck, and limbs, and a characteristic yellow "L" is mirrored across the top of the head. Males and females differ in appearance. Males have longer, thicker tails and longer claws on the front feet than females, but adult females can grow up to twice the size of adult males. The adult female shell ranges from 12 to 27 cm (5 to 11 in.) in length, while the adult male shell ranges from 9 to 15 cm (3 to 6 in.) in length.

False map turtles select large rivers and reservoirs that have many basking sites and some aquatic vegetation. In South Dakota, false map turtles are primarily associated with the Missouri River. With a highly aquatic lifestyle, false map turtles usually do not stray far from the water. The turtle’s diurnal (daytime) activities limit opportunities to view basking false map turtles. This is a rather shy turtle that becomes skittish when it senses danger, escaping potential threats by entering the water. Along the Missouri River, false map turtles bask on partially submerged logs or stones of deeper waters. Other turtles usually avoid these inaccessible basking sites. False map turtles bask for up to two hours during the day.

False map turtles typically breed in the spring. Courtship occurs in the water where males display an unusual mating ritual. Males swim around females eventually stopping to face them. Once in this position, males begin drumming females on the head with the claws on their front feet. While touching the females, males bob their heads up and down. Eventually, the males stimulate the females to sink to the bottom of the water, signaling males to mount females and mate.

Usually in June or July, females lay up to 16 eggs in well-drained areas. Females dig several nests in sandy shoreline areas along the Missouri River, with some nests dug to serve as decoy nests. Sandbars are often primary nesting sites, since they are near water and have minimal vegetation. Nesting sites are very important to the survival of false map turtles. Unfortunately, nesting sites are being depleted through flood control (e.g., dams) of the Missouri River and riprap placement along the Missouri River shorelines. After two to three months of incubation, eggs hatch and hatchlings appear. Incubation temperatures determine the sex of the turtles; higher temperatures produce female turtles, while lower temperatures produce male turtles. False map turtles may produce up to three groups of eggs (clutches) per year, though this is rare in South Dakota.

False map turtles normally feed early in the morning on aquatic insects, fish (especially dead fish), aquatic plants, and crayfish. Individuals overwinter in the mud on the bottom of the river. Dry winters pose a large threat for false map turtles. With a higher potential to freeze in shallow waters, false map turtles experience increased winterkills.

Currently, Sarah Bandas, a graduate student from South Dakota State University is conducting an inventory of wild turtles in South Dakota, which is a project being funded by a special allocation to South Dakota Game, Fish and Parks called the Wildlife Conservation and Restoration Program. Surveying methods include using hoop nets with fish bait to capture turtles in shallower waters. False map turtles were documented in the southern portion of the Missouri River, though not in great numbers.

At one time, false map turtles were common turtles of the northern Missouri River, a common resident of Lake Oahe and Lake Sharpe. Now, the false map turtle is a state-protected species (state-threatened). At present, false map turtles are generally rare in Lake Oahe and Lake Sharpe, although they can be locally common. False map turtles are more regularly found below Gavins Point Dam. Natural and man-made factors affect false map turtles throughout their range. Natural factors include natural weather extremes, such as dry spells. Man-made factors consist of agricultural run-off, flood control (e.g., dams), and urbanization, all of which cause habitat degradation or destruction.

Loss of habitat plays a major role in the numbers of false map turtles since these turtles already face a limited range. False map turtles are rare residents in certain areas of the Missouri River, and where false map turtles commonly dwell in the Missouri River, their numbers are no longer as plentiful as in the past. False map turtles depend on sandy shorelines and large, natural river systems. Because the Missouri River continues to change ecologically, false map turtles may be affected well into the future. For this species to remain a Missouri River resident or, more specifically, a South Dakota resident, we need to maintain and enhance protection along the Missouri River. Hopefully, this will ensure the existence of false map turtles as well as other rare or protected species of the Missouri River for future generations to enjoy.

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