Earth Notes
4:23 pm
Wed July 6, 2011

Earth Notes: Mud Turtles

Flagstaff, AZ – Most of the Southwest is hardly turtle habitat. But in the scattered places where water rests in the open, or runs slowly, you can find them in mild weather.

In central Arizona, some of those aquatic animals are Sonoran mud turtles. As their name implies, most live mainly to the south. But Sonoran mud turtles do range as far north as Montezuma Well in the Verde Valley and into Oak and Beaver creeks, where they're fairly common.

Their domed shells, about six inches long, are olive green to brown and are sometimes coated with green algae. They spend part of their lives in the ground, hibernating in winter cold or estivating in summer heat. Sometimes they're seen on land or out basking on a log in the sun.

But these turtles do need water, in the form of pools, ponds, cattle tanks, or streams. Sonora mud turtles are well tuned to the summer monsoon season. The females lay eggs in summer in underground nests, and the eggs hatch a year later, just before or during the rainy season, when moisture and food are available. Though conditions are favorable then, the quarter-sized hatchlings are vulnerable to foxes, skunks, raccoons, even crayfish.

At Montezuma Well, mud turtle numbers have been on the downturn, possibly because of competition from nonnative turtles called sliders. Now almost all the sliders have been removed, and U.S. Geological Survey biologists are monitoring the native mud turtles to see how they fare.