Ouachita Map Turtle Graptemys ouachitensis
by Jeff LeClere
PROTECTED, except from the Mississippi River and its connected backwaters. Here, it is legal to take with a valid fishing license. These turtles may be trapped, or taken by hand, hook and line, or turtle hook. The possesion limit 100 pounds for live and 50 pounds for dressed turtles.
This is a medium to large sized Iowa turtle that grows 6 to 10 inches carapace length. The shell is dark brown, olive, or black. This turtle gets its name from the light yellow lines that form a reticulated or map like pattern on the back, but this pattern is usually obscure on adults. Old females have dark blotches on the back and plastron. There is a vertebral keel on the back that is rather prominent even in adults. The marginals on the rear of the carapace are serrated. The plastron is dull yellow with black lines and swirls. The head and limbs are black or dark olive. There are light yellow lines on the head and limbs.
There are three large blotches on each side of the head that will distinguish Ouachita map turtles from all our other map turtles. One is behind the eye, one is just below the eye, and the third is just below the mouth line. These blotches are big enough to be seen with a good pair of binoculars, but be careful. Less than three light lines reach the eye.
Females grow much larger than the males. Adult males have long claws on the front feet, and a long, thick tail with the cloacal opening past the edge of the carapace. Young have brighter shells and light yellow or orange rings that fades quickly, a dark pattern on the plastron, and a pronounced vertebral keel.
The Ouachita map turtle Graptemys ouachitensis ouachitensis is the only subspecies found in Iowa. The Ouachita map turtle was once considered (and still is, by some) a subspecies of the false map turtle, Graptemy pseudogeographica, until Vogt (1993) elevated it to a full species. Even so, Vogt (1981) and Ewert (—-) mention that these two races hybridize (or intergrade) and that young from a single clutch will represent both forms. Adults in the Mississippi River will sometimes be intermediate in appearance.
The Ouachita map turtle is found in the Mississippi River, however, they do not range very far along the Mississippi River tributaries at all. They are found in large numbers in the Mississippi, often usually out numbering the false map turtles.
This turtle is nearly restricted to the Mississippi River in Iowa. Lakes and oxbow ponds are utilized only when close to the Mississippi River. They prefer sandy or silty bottoms.
Ouachita map turtles have a shorter active season when compared to some other Iowa turtles. They are active from April to October. They are diurnal and spend a considerable amount of time basking. They forage for short periods during the day. They are very aquatic and do not roam far from water. They bask on anything above the water as long as it is away from shore in deep water. Snags and fallen trees with many limbs provide ideal basking areas and a large number of turtles may bask at this site. Approach very slowly and quietly as these turtles are extremely wary. If one dives, they all dive. The turtles remaining (if any ) are the painted turtles. They resurface fairly quickly, but will remain very cautious and in the water until the danger has past.
Ouachita map turtles breed in spring and fall, and females may deposit three clutches of eggs a year (Ernst, Lovich, and Barbour, 1994), but Minnesota specimens probably produce only one or two. They nest in late May through June and again in July. I have observed a female Ouachita map turtle nesting long the Mississippi River in Louisa County on 5 July. The soil was very sandy and it was nearing dusk. Ouachita maps usually do not migrate long distances to lay eggs. Females may dig a few “false nests” before actually depositing 12 to 22 eggs. They often nest on sand bars, where possible.
The young emerge in August or September or they may overwinter in the nest (Vogt, 1981). They mature at about 14 years of age.
Ouachita map turtles are omnivorous. They do not consume near the amount of snails and clams that common map turtles do, and will feed on the surface of the water more often than the false map turtle. This is helpful when all three species occur together in the Mississippi River. Ouachita maps will eat dead fish, aquatic insect larvae, and a good amount of vegetation. Males are more carnivorous while females are more herbivorous by comparison.