Habitat Utilization by the Turtle, Graptemys geographica, along a River

Abstract

Differential habitat utilization by size classes of map turtles, Graptemys geographica, was examined in the Raystown Branch of the Juniata River, Pennsylvania. A total of 924 captures or sightings was made of 92 males, 76 females, and 11 juveniles. Significant positive relationships were found between size (carapace length) and four variables: distance from shore, water depth, surface current and swimming speed. Medium-sized turtles were pushed off basking sites by large turtles significantly more often than the inverse. Relative swimming speeds, basking interactions, and predator avoidance may all play a role in size-related differential habitat utilization.