Distribution:Cagle's map turtle has a limited distribution; the southernmost of any Graptemys species. This species is restricted to the Guadalupe and San Antonio River watersheds of south-central Texas, but may now be extirpated in the San Antonio drainage.

Habitat: Habitat in the Guadalupe River system consists of limestone or mud-bottomed streams with moderate current, and numerous pools of varying depths. In addition, it may be found in slow moving water, 1-3 m deep, behind impoundments (Vermersch 1992).

Behavior: Cagle's map turtle is diurnal and spends much of its time basking on logs, rocks, and cypress knees. Haynes and McKown (1974) observed that logs that had fallen into the river, but were still connected to the bank, were not used as basking structures by Cagle's map turtle. Similar to other map turtles, this species is wary and difficult to approach. With the exception of nesting, this species rarely comes onto land (Vermersch 1992).

Reproduction: Limited biological data exist on this species. Haynes and McKown (1974) observed and collected hatchlings from September through November, indicating a late spring to early summer nesting season. As many as three clutches may be laid yearly containing one to six eggs (Vermersch 1992). Eggs are deposited in nests located near the water in cavities approximately 15 cm deep. Gender development is temperature-dependent, with high incubation temperatures producing only females and low temperatures producing only males (100 percent males at < 28 ^oC; 100 percent females at 30.5 ^oC) (Wibbels et al. 1991). The estimated pivotal temperature (approximately 30.0 ^oC) is higher than those reported for other species of Graptemys in North America.

Food Habits: Adults primarily feed on insects (caddisfly larvae and larval cases) and snails, and may incidentally ingest algae and plant matter such as bark. The diet of juveniles consists of small gnat-like insects with incidental pieces of bark and grass (Haynes and McKown 1974).

Populations: This turtle is the dominant turtle in certain parts of the Guadalupe watershed (Vermersch 1992).