This is a common musk turtle (Sternotherus odoratus) from southern Indiana. These are small turtles ranging in size from 3-5.5 inches. They are strongly aquatic and are mainly carnivorous eating insects, snails, fish, tadpoles, and crayfish as well as some algae and vegetation. They are commonly called stinkpots because of the glands on the plastron that secrete a smelly musk.
The Bearded Biologist 