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This site was created by students in the herpetology class at Towson University. Site last updated: 05/21/07.
Acknowledgements: Herb Harris - Range Maps; Mark Tegges - Photography; Dan Lapascha & Gigi Forester - TU Herpetology Logo
Northern map turtle
(Graptemys geographica)
Description
The map turtle is named for its carapace which is green to olive-brown with a reticulated pattern of thin yellow-orange lines loosely resembling a topographic map. The posterior edge of the carapace is serrated and there is moderate dorsal keeling. Marginal scutes are yellowish with dark, circular patterns underneath. The plastron is yellow and patternless in adults. The skin is a dark green color with plentiful yellow striping and a yellow spot, often triangular in shape, located behind each eye. The map turtle appears to have big lips due to the wide, smooth and lightly colored jaw surfaces. This medium-large turtle varies greatly in size by sex. Males range in length from 8.9 – 16.0 cm while females are much larger ranging from 17.8-27.4 cm in length with a proportionately larger head. Hatchlings have a strongly keeled carapace with more vibrant coloration and black-bordered plastral scute seams.
Habitat
Preferred habitats are deep, slow-moving rivers and lakes with muddy bottoms, ample vegetation and abundant basking sites.
Breeding
Mating season extends from spring through fall. Males exhibit courtship behavior that includes swimming in front of the female, snout nudging and head bobbing. Nesting occurs from May to mid-July. Females lay 9-20 elliptical eggs in soft soil or sandy bottom nests. Hatchlings emerge from the nest in August or September unless they overwinter. Overwintering hatchlings will emerge in May or June of the following year.
Distribution in Maryland
Range map adapted from Harris, 1975.
Links
http://animaldiversity.ummz.umich.edu/site/accounts/information/Graptemys_geographica.html
http://graptemys.com/ggeographica.htm
http://www.dgif.state.va.us/wildlife/species/display.asp?id=030065