Description: Escambia Map Turtles are a moderately sized, sexually dimorphic species. Adult females have an average carapace length of 11 inches. Males are typically less than half the size of females with an average carapace length of 5 inches. The carapace is high-domed, and triangular in the cross-section. The carapace is an olive to light-brown color with a vertebral keel. Along the vertebral keel is a broken black stripe. The keel is prominent in males and juveniles, but more rounded in adult females. The keel is most pronounced on vertebrals two and three, with the latter much lower than the first. The marginal scutes have yellow circular borders that curve inward. The pleural scutes have yellow to orange bars with black borders on the distal portion. This forms a reticulating pattern. The pale yellow plastron is hingeless, and relatively flattened in both sexes. An inconspicuous dark pattern follows the seams of the plastron, and is more pronounced on seams running horizontal to the body.

The head and limbs are a brown to olive color with yellow markings. Occasionally, these markings can be a dark yellow-orange color. An interorbital blotch on the top of the head ends anteriorly in a distinct three-pronged shape (nasal trident). Each eye has postorbital markings that end in rounded posterior edges. The interorbital blotch is not connected to the postorbital markings. Two neck stripes form oval tips at the back of the head that may separate into supraoccipital blotches. The underside of the jaw possesses medial longitudinal striping. The limbs and tail are striped.

Female Graptemys ernsti have a much larger head than males. Males have a narrow head, while a female's head is disproportionately wide compared to her body. Males have longer tails with the vent, or cloacal opening, located nearer the tip, beyond the rear edge of the carapace. This allows the vent to extend outward far enough during copulation. Females have narrower tails, with the vent underneath the rear edge of the carapace. Large adult females may develop a humpback due to a slope of the first vertebral scute.

Habitat: Graptemys ernsti is highly aquatic, and only found in large to medium-sized rivers and streams that provide logs and deadwood for basking. Fast-moving waters are preferred. These waterways usually have gravelly or sandy bottoms. Two specific types of habitats have been described. The species can be found in rivers with steep banks that have rough substrate such as limestone and bedrock with small sandbars. These habitats do not provide many opportunities for basking. The preferred habitat is in rivers and streams with sandy banks and larger sand bars. More erosion in these habitats provides more woody debris and thus sites for basking. Although located relatively close to the Gulf of Mexico, this species does not often reside in estuaries or floodplain swamps. Instead, it prefers freshwater waterways with access to underwater retreats.

Range: >Graptemys ernsti (Escambia Map Turtle) occurs only in the Southern United States, in a relatively small range in the Pensacola Bay drainage system located in southern Alabama and western Florida. This includes the Escambia, Yellow, Conecuh, and Shoal Rivers. Recently, G. ernsti was found to inhabit the Pea and Choctawhatchee Rivers in Alabama, which drain into the Choctawhatchee Bay. Here, G. ernsti is sympatric with Graptemys barbouri. Researchers are not sure if the species is native to this area or was perhaps introduced via human activity. Escambia Map Turtles are apparently not found downstream in the Florida portion of the Choctawhatchee River.

Found in these States: AL | FL

Diet: Graptemys ernsti is carnivorous. Females are able to feed primarily on mussels, snails, and sometimes crayfish due to having wider, more powerful jaws than males. Males will also feed on mussels occasionally, but will mostly feed on fly larvae, dragonflies, snails, and beetles. Juvenile females will eat mostly insects, but will transition to mussels and snails when they reach optimal size.

Reproduction: A male G. ernsti may reach sexual maturity in as few as three years, while females are not considered to be mature until about thirteen to eighteen years of age. Mating activity has been observed throughout September to November. Courtship takes place in the water. The male will swim in front of the female and vibrate his head on the female's snout in a vertical motion. The female will withdraw her head slightly, and the male will swim behind her to begin copulation.

Females nest from late April to late July, when water levels are the highest. Eggs are usually laid in sandbars along river bends. The female will dig a small hole a few inches deep with her hind feet, and about 10 to 50 feet from the water’s edge to lay a single clutch of elliptical, soft shelled eggs. Eggs may absorb water and later become nearly spherical. Clutch size is dependent on female carapace length. Larger females will produce larger clutches. Clutch size varies from 6 to 13 eggs; average clutch size is about 7 eggs. The average number of clutches per season laid by a single female is about four. This is also dependent on female size.

Status: As of 2011, Escambia Map Turtles are listed as "near threatened" (IUCN Red List of Threatened Species). They are losing their habitats to human expansion and water pollution; survival rates have decreased due to water pollution in certain areas brought on by nearby factories. The water pollution affects them primarily by decreasing their prey base, and thus causing them to die of starvation. Use of basking turtles as targets for firearms is deplorable, and can quickly reduce populations. Some commercial collection for the pet trade may also be affecting their numbers.

Subspecies: None

Taxonomy: