Affectionately known by some as “free-range pancakes,” Illlinois' two softshell turtle species—the spiny softshell (Apalone spinifera) and the smooth softshell (A. mutica)—are easily distinguished from other turtle species by their soft, leathery carapace/shell.
These softshell species are similar in appearance but can be distinguished by their nostrils. The spiny softshell has U-shaped nostrils (projections between the nostrils) while the smooth softshell has round nostrils that lack projections between them.
As with many turtle species, both spiny and smooth softshells can extend their neck far from their body and do not necessarily enjoy being held by humans. If attempting to identify a softshell turtle, we recommend holding it far from your face while observing the nostrils.
The spiny softshell ranges as far north as Minnesota and south to northern Mexico. It prefers the slower-moving water of rivers, ponds, and lakes with mud or sand bottoms. These softer substrates allow it to bury itself for cover, camouflage itself while feeding, and hibernate during the colder months. It feeds primarily on aquatic insects and occasionally crayfish and fish.
Breeding occurs in late spring, where the female spiny softshell generally lays between 10–30 eggs that get buried and take 3–4 months to incubate and hatch.
An adult spiny softshell can live up to 50 years!
The spiny softshell is one of the most common turtle species in the Illinois River along with the red-eared slider. INHS Illinois River Biological Station researchers commonly catch these creatures in the hoop nets they use to sample fishes.
Unlike its common relative, the smooth softshell is Illinois state endangered. Its declining numbers have been attributed to agricultural runoff, pollution, and siltation.