Alabama map turtle

The Alabama Map Turtle

The Alabama map turtle, scientifically classified as Graptemys pulchra, is a distinct species of emydid turtle native to the southern United States. Its most recognizable feature is a prominent black stripe running down the center of its back, which is accompanied by knob-like protrusions that gradually wear down as the turtle ages. This turtle is endemic to the Mobile Bay drainage basin, inhabiting the flowing water systems of Alabama, Georgia, Florida, Mississippi, and possibly Louisiana.

Description and Characteristics

Distinguishing the Alabama map turtle from other species within the Graptemys genus involves examining several key features. While males are relatively small, typically measuring between 9.0 and 12.7 cm in carapace length and retaining much of their juvenile coloration, females are significantly larger, ranging from 18.0 to 29.2 cm. Adult females possess notably large heads, an adaptation for crushing snails and mollusks, and their patterns become less distinct, appearing drabber than those of juveniles and males. The carapace, or upper shell, is generally olive to dull green, with a subtly visible black stripe in adults. Juveniles exhibit a darker stripe on a more olive carapace. The plastron, or bottom shell, is yellow and unhinged, with a notch at the rear. The head is typically brown to olive, marked by a prominent light green to yellow patch situated between and behind the eyes.

Habitat and Behavior

The Alabama map turtle prefers lotic, or flowing water, environments, particularly large coastal plains streams that support substantial populations of mollusks. There are notable differences in habitat preference based on age and sex; juveniles and adult males favor shallow waters with accessible basking logs, while adult females are more inclined to inhabit deeper waters and prefer sandbars with a specific coarseness.

Diet and Reproduction

As omnivores, Alabama map turtles consume a varied diet including mollusks, insects, carrion, and vegetation. The imported oriental mussel (Corbicula maniliensis) is a primary food source for adults. Smaller individuals and juveniles tend to feed more heavily on insects. Reproduction involves males reaching sexual maturity in three to four years, while females mature much later, around 14 years of age. Mating typically occurs in the autumn. Females lay an average of 29 eggs per season, usually on exposed sandbars located between 1 and 20 meters from the water's edge. The incubation period lasts approximately 74 to 79 days at a temperature of 29 °C. Nest predators commonly include fish crows and raccoons.

Conservation Status

The Alabama map turtle is designated as Near Threatened by the International Union for Conservation of Nature (IUCN). It is considered at high risk of extirpation due to its confinement to specific river systems and susceptibility to human disturbances such as habitat destruction and fragmentation. In 2024, the U.S. Fish and Wildlife Service listed the species as threatened, primarily based on its similarity in appearance to the Pearl River map turtle, which can complicate conservation efforts.