BARBOUR’S MAP TURTLE } Graptemys barbouri
DESCRIPTION: The Barbour’s map turtle is a medium- to large-sized turtle, with males growing to about 3.5 to 5.5 inches long and females reaching 6 to 12.5 inches. Its shell keel is exaggerated as a hatchling but becomes less prominent with age. The shells of both males and females are dark brown or black with light yellow or green markings; the chin has a light bar that generally follows the curve of the jaw.
HABITAT: Barbour’s map turtles are found in clear, limestone-bottomed streams and large rivers with abundant basking sites in the form of snags and fallen trees. Use of silty channels is also widespread. Typically they prefer to bask on large logs rather than small branches. They are inactive at night, and rest on the bottom in limestone depressions when the water becomes cold. Males and juveniles prefer the brush along the sides of the river, while females tend to prefer the deeper water and bask further into the river. Females bury their eggs at the water’s edge.
RANGE: Florida — in the Apalachicola, Chattahoochee and Chipola; Alabama — in the Chattahoochee; and Georgia — in the Chattahoochee and Flint river systems.
BREEDING: Males reach sexual maturity around three to four years, but females require any where from 14 to 20 years to reach sexual maturity. Males attract females by approaching them with their necks extended, in an attempt to be face-to-face. The male then undertakes a courtship routine in which he touches the sides of the female’s head with the inner surfaces of his front legs for a few seconds. Females have a prolonged nesting season that lasts from late April to early August. They have a small clutch size, with 7-10 eggs laid in May and June. The sex of the turtle is determined by the temperature at which the eggs incubate, not by chromosomes as with humans. Eggs at 77 degrees Fahrenheit produce only males, whereas eggs at 86 degrees Fahrenheit produce only females. Recruitment is often affected by raccoons and crows that feed heavily on the eggs and young map turtles.
LIFE CYCLE: The average life expectancy of map turtles ranges from 15 to 20 years. The longest observed lifespan of a Barbour’s in captivity was over 31 years, at the National Zoo in Washington, D.C.
FEEDING: Adult females feed almost entirely on mussels and snails, while adult males and juveniles mainly feed on insects and insect larvae. But they are also opportunistic eaters, occasionally feeding on fish.
THREATS: Habitat destruction and modification, overcollection for the pet trade and human consumption, dredging, barge traffic, plant overgrowth of nesting sites and pollution.
POPULATION TREND: This turtle is declining.