The flat, almost circular upper shell (the carapace) of the eastern spiny softshell turtle resembles a pancake, and it is covered by leathery skin rather than the hard scutes found on most turtle shells. In adult males, there are tiny projections on the entire surface of the carapace that make the shell feel like sandpaper. In adult females, the shell may be smooth, but there are several large spines or cone-like projections at the front of the carapace.
Large females may attain a shell length of 48 cm (19 in.). Males are usually smaller, up to 23 cm (9 in.) long.
These turtles are very aquatic, occurring in rivers and large lakes, in quiet portions of water, where they prefer areas of sand and mud. They often lie with only their nostrils out of the shallow water. They are active during the day, eating crayfish, aquatic insects and fish.
Their completely webbed large feet allow them to swim rapidly, and if basking they will quickly dash into the water at the slightest disturbance. As a consequence, they are rarely seen. They are savage if molested, and capable of inflicting significant injury with their razor-sharp jaw edges.
In Canada, eastern spiny softshell turtles have been found in southern Ontario and southwestern Quebec: in Lake Erie and Lake Ontario, in the Ottawa and St. Lawrence rivers and in Lake Champlain. They also occur in the United States, from western New York to Wisconsin and south to the Tennessee River.