Northern Map Turtle

Scientific Name: Graptemys geographica

Named for its markings, this turtle has lines on its upper shell that look like a topographical map.  The carapace (upper shell) is olive green or grey-brown with fine yellow lines and has a distinct ridge (keel) along the center and serrations along its back edge.  Both the head and legs have an intricate pattern of bright yellow lines.  The plastron (lower shell) is cream to light yellow in adults, but it has dark lines along the edges in juveniles.  Females get much larger than males, growing up to 27cm in carapace length, whereas males grow to only 13cm long.  Another distinguishing feature is the yellow spot behind the eyes.

These turtles have a large area of their mouths in which to crush their food.  Young turtles and males eat insects and crayfish, whereas the larger females are able to consume clams, snails, and small fish.  Like the painted turtles, northern map turtles are also frequently seen sunning themselves on fallen logs and rocks in large bodies of water.  However, this species much more skittish, dropping into the water at the slightest incident.

Female northern map turtles take at least a decade to reach breeding age.  The size of the clutch is between 10-20 eggs.  The eggs are oval, about 3.2cm long, and have a flexible shell.  After being laid in summer summer, the eggs will hatch in the fall, but they are capable of remaining submerged in the ground over winter to hatch in the spring, depending on the conditions.

Facts are from SARO (Species at Risk in Ontario) and the Ontario Turtle Conservation Center.
Photos are courtesy of DTW volunteers.