Habitat Map turtles are predominantly lotic, living in moving water, such as rivers and larger creeks, streams, and bayous. The northern and wide-ranging Mississippi River species (
G. geographica,
G. pseudogeographica,
G. ouachitensis) tend to inhabit more diverse habitats, including sloughs, oxbow lakes, and backwater areas of river bottoms, as well as lakes and occasionally even ponds and marshlands. Other species use these environments much less frequently, or as juveniles or during seasonal flooding, and a few species have never been reported from areas beyond the main channels of their respective river systems (e.g.
G. gibbonsi,
G. pearlensis,
G. sabinensis). Several species will inhabit manmade reservoirs in their river systems, while other species are very uncommon in such impoundments (e.g.
G. oculifera,
G. versa), and still others are entirely absent from reservoirs (e. g.
G. caglei). With few exceptions (
G. barbouri,
G. flavimaculata,
G. nigrinoda), most species do not occur in tidally influenced waterways,
estuaries, or
brackish waters, which are occupied by their closest relative the diamondback terrapin (
Malaclemys terrapin). The upstream distributional limits of many species are often associated with the level of sunlight penetration through the forest
canopy. Larger, wider waterways allow sunlight to reach the surface, providing for the growth of aquatic vegetation and algae (food) and basking sites for
Graptemys populations. Smaller streams in the shadow of forest canopies, or that receive brief patchy sunlight, are rarely inhabited by
Graptemys. The natural meandering of rivers,
riparian forest, and fallen trees and deadwood in the water are all key and vital elements to sustain most map turtle populations, particularly the
Gulf Coast species. The outer bend in a river is typically the deeper side, with the stronger current of the main channel, eroding and cutting into the outer bank and falling trees of the riparian zone forest as it does. While the inside of the bend is shallower, with a slower current, dropping silt deposits and building beaches and sandbars. The meandering course maintains a diverse spectrum of water depths, temperatures, currents, soft and hardpan bottoms, as well as fallen trees and logs that get lodged in the bends. Beaches and sand bars are essential nesting sites. The presence of partially submerged deadwood and trees are critical, not only for basking, but for the growth of
algae,
bryozoans,
sponges, snails, insects and their eggs larva that live in the growth, which are important food items for turtles.
Longevity Complete and accurate longevity records for map turtles are lacking. A review of zoo records published in 1992 identified the maximum period of time that many species of
Graptemys lived in captivity in North American zoos, ranging from eight to 35 years, including: Barbour's map turtle (
G. barbouri) 31 years 8 months; false map turtle (
G. pseudogeographica ssp.) 32 years and 6 months; Mississippi map turtle (
G. pseudogeographica kohnii) 35 years 5 months. However, these records involve turtles that were acquired by the zoos as adults from the wild, or of unknown origins and of undetermined ages. Therefore the records only reflect the period of time that an individual turtle was maintained at the institutions before it died, not the full lifespan of the individual. Subsequently, the longevity of two female Barbour's Map Turtles (
G. barbouri) of unknown ages and origin at the
Columbus Zoo were reported at 37 and 43 years. Herpetologist Carl Ernst noted northern map turtles (
G. geographica) and Alabama map turtles (
G. pulchra) likely live well over 20 years in the wild, Based on records of other turtles in the
Emydidae family, it is likely
Graptemys longevity exceeds these records significantly, perhaps by decades. ==Conservation==