Northern Map Turtle

Graptemys geographica (State Status: S1; critically imperiled)

Description

While relatively common in the Midwest and northern US, the Northern Map Turtle may rarely be encountered in extreme northeast Mississippi. Shell is flatter than other map turtles in the state, with a reduced ridge of dorsal spines. Shell color is brown or olive with light yellow “map” network of lighter marks throughout. The species may be identified by its separated triangular or rounded spot behind the eye (Guyer et al., 2015). These map turtles exhibit sexual dimorphism, with females sporting megacephalic head development to aid in crushing shelled organisms such as mollusks. Map turtles often bask on branches, logs, and other vegetative matter, often angled at 45°.

Megacephalic adult female, Tishomingo Co. (MS), © Kevin Narum

Identifying Traits

  • Separated dot behind eye
  • Reticulation or ring patterns of light orange or yellow on carapace
Range

Habitat

Rivers and lakes within their range. May be found in the Tennessee River system in Northeast MS

Behavior

Map turtles often bask on branches, logs, and other vegetative matter, often angled at 45°. 

Diet

Females use their large jaws on freshwater invertebrates such as snails and mussels

Young individual, Tishomingo Co. (MS), © Grover Brown
Adult male, Tishomingo Co. (MS), © Grover Brown