Habitat alteration and destruction have contributed to the demise of the turtle in western Washington. These turtles are very shy and will dive into the water at the least disturbance. Food items include various insects, frogs and frog eggs, fish and carrion. Mating in the wild takes place in the spring and possibly also in the fall. Nesting occurs from late May until the middle of July.
Females find a suitable site, usually with dry soil, sparse vegetation and a southern exposure.
A hole is dug by softening the soil with urine and then scooping out the soil alternately with hind feet. They will deposit a clutch of three to 13 eggs. After laying the eggs, the hole is filled with a mixture of vegetation and dirt to provide an air space, and covered with wet soil as a plug to keep the eggs in a humid environment. This process can take from two to four hours. Incubation takes 90-130 days, depending on summer temperatures.