Reptiles
Texas Map Turtle
Graptemys versa · also called Texas map turtles
Basking on a sun-warmed log along the Colorado River, a Texas map turtle shares its perch with several others, an entire species whose global range begins and ends within this single central Texas watershed.
Overview
The Texas map turtle, Graptemys versa, is a keeled, sexually dimorphic turtle found only within the Colorado River system of central Texas. Its striking male-female size and jaw differences, along with its extraordinarily narrow single-river range, make it one of the more geographically and physically distinctive map turtles in North America.
Two very different jaws in one species
A male and female Texas map turtle can look almost like different species, the female’s noticeably wider, crushing jaw opening up a food source her smaller, narrower-jawed male counterpart simply cannot access, letting one species effectively split a single food supply two ways.
Status
Least Concern — present and stable across suitable habitat within the Colorado River system of central Texas, its sole home anywhere in the world.
Texas Map Turtle: common questions
Why do female Texas map turtles have wider jaws than males?
A female Texas map turtle develops a considerably wider head and jaw than a male, an adaptation that lets her crush hard-shelled prey such as snails and mussels, food sources a male's narrower jaw is not well equipped to handle, allowing the sexes to specialise on somewhat different parts of the same food supply.
How restricted is the Texas map turtle's range?
The Texas map turtle is found only within the Colorado River system of central Texas, making it endemic to this single river drainage and found nowhere else in the world, a genuinely narrow range for a freshwater turtle species.
Does the Texas map turtle bask in the sun?
Yes, a Texas map turtle basks readily on exposed logs, rocks, and sandbars, often alongside other turtles, though it is quick to slip back into the water at the first sign of an approaching disturbance.
Where does the Texas map turtle live?
The Texas map turtle is native exclusively to the Colorado River system of central Texas, making it endemic to this single watershed and found nowhere else.