Cagle's map turtle (Graptemys caglei) is a species of turtle in the family Emydidae. The species is endemic to Texas, where it is native to the Guadalupe, San Antonio, and San Marcos Rivers. Cagle's map turtle has intricate patterns on the carapace and plastron, as well as serrated edges on the posterior of the carapace, as is typical of all map turtles. It is smaller than most map turtles, and very sexually dimorphic, with males reaching only 4 in (10 cm) straight carapace length, while females can exceed 7 in (18 cm) in straight carapace length. The specific name, caglei, is in honor of American herpetologist Dr. Fred Ray Cagle (1915-1968). Adult females of G. cagle feed mainly on molluscs, but males and juveniles feed mainly on aquatic insects. Like all turtles, G. caglei is oviparous. A sexually mature female may lay up to three clutches of eggs in a year. Clutch size is small, only one to six eggs. Graptemys is a genus of freshwater turtles containing 14 species, commonly known as map turtles. Graptemys are small to medium-sized turtles that are sexually dimorphic, with females attaining as much as twice the length and ten times the mass as males in some species. Depending on the species, adult males range from 7–16 cm (2.75–6.25 in), adult females 10–29.5 cm (4–11.62 in), and hatchlings 2.5–3.8 cm (1–1.5 in). although some sources indicate female Barbour's map turtles (Graptemys barbouri) grow to 33 cm (13 in) in length. Most species have a distinctive dark pigmented keel that is often notched or serrated running down the center of the carapace and serrated scutes on the rear margin. The head, neck, and limbs exhibit bold patterns of yellow (occasionally orange or red) lines and spots against darker green, olive, or black base colors. The patterns on the head can be important characters in identifying the various species. The common name "map turtle" is derived from the intricate patterns on their shells that are suggestive of topographical maps, although the patterns are more apparent in some species than others, and often become obscure in older specimens. Some species are occasionally called "sawbacks", in reference to the serrated keels on their shell.