Overview

The Bog Turtle (Glyptemys muhlenbergii) is the smallest turtle species in North America, reaching only 4.5 inches in maximum carapace length, though shell lengths typically average between 3 and 4 inches. Bog Turtles are characterized by their small size, dark coloration, and large yellow to orange blotches on both sides of the head. These blotches vary in coloration from yellow, yellow-orange, orange, and orange-red from population to population. Bog Turtles have a black, brown, or mahogany colored carapace and an unhinged plastron that is typically black with yellow or cream colored spots along the midline. There is a high degree of sexual dimorphism in Bog Turtles, making it fairly simple to distinguish between males and females. The plastron in females is flat and is strongly concave in males. The tail of adult females is short with the vent barely extending beyond the rear edge of the plastron. While in males, the tail is long and muscular with the vent well beyond the rear edge of the carapace. The northern populations of Bog Turtles are found in western Massachusetts and Connecticut, New York, New Jersey, Pennsylvania, Delaware and Maryland. The southern population, separated from the northern population by 250 miles, begins in southwestern Virginia and ranges through North Carolina, Tennessee, South Carolina and northern Georgia. Bog Turtles in the southern population are more scattered in their range than in the northern population and live at higher elevations of up to 4500 feet.

Habitat

Throughout their range Bog Turtles are found in seepage or spring-fed emergent freshwater wetlands associated with streams or bordered by wooded areas. These wetlands have a variety of micro-habitats that include dry pockets, saturated areas, and areas that are periodically flooded that the turtles depend on for foraging, nesting, basking, shelter and other needs. The Bog Turtle’s preferred habitat, sometimes called a fen, is slightly acidic with continual wetness, which creates great plant diversity. The Bog Turtle uses soft, deep mud to shelter from predators and the weather, and the saturated areas provide the most favorable locations for hibernation in the winter. Bog Turtles are very sensitive to habitat changes and have suffered greatly from habitat loss and degradation such as wetland filling, fragmentation, and drainage. Due to unchecked natural succession, many bogs are overgrown with trees, which can dry out the bog and shade out the moss and grass habitats Bog Turtles prefer. Other reasons for their decline include nonnative and native plant species invasions, increased nutrient load from runoff and wood encroachment. The development of neighborhoods, roadways, farms and reservoirs obstruct the Bog Turtle’s movement between wetlands, thus inhibiting the establishment of new colonies.

For more information, download the Bog Turtle Fact Sheet