False Map Turtle
Graptemys pseudogeographica

by Jeff LeClere

Status

The false map turtle has no status in Minnesota.

Description

This is a medium to large sized Minnesota turtle that grows 5 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. A backwards L is present behind each eye. There are no large blotches orspots found on the head, and three lines reach the eye. This distinguishes falsemap turtles from all our other map turtles. 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 markings, a dark pattern on the plastron, and a pronounced vertebral keel.

Subspecies

The false map turtle Graptemys pseudogeographica pseudogeographica is the only subspecies found in Minnesota. The Ouachita map turtle Graptemys ouachitensis was once considered (and still is, by some) a subspecies of the false map turtle, until Vogt (1993) elevated it to a full species.

Range

The false map turtle is found in the Mississippi and St. Croix Rivers at least to Pine County. They extend west into Minnesota via the Minnesota River to South Dakota. They are common in the Mississippi River, but they have a lot of competition from the other map turtle species.

Habitat

This turtle is found only in slow portions of larger rivers in Minnesota. Lakes and oxbow ponds are utilized only when close to a good sized river.

Habits

False map turtles have a shorter active season when compared to other Minnesota turtles. They are active from late April to September. They are diurnal and spenda 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.

False map turtles breed in spring, 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. They 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.

Food

False map turtles a large amount of aquatic insects. They also consume aquatic plants, fish (especially dead fish), crayfish, and other aquatic life.