Elliptio crassidens, the elephant-ear, is a species of freshwater mussel, an aquatic bivalve mollusk in Unionidae, the river-mussel family.

After living parasitically on the host fish for several weeks, juvenile clams break free and fall to bottom of the river where they burrow and develop into adult mussels.

Common predators include otters, raccoons, muskrats, herons, egrets, and a variety of fish.

Although widespread, elephant-ears are relatively rare in the Midwest, but are locally abundant in some parts of the Ohio and White rivers of Illinois and Indiana.

[5] Elephant-ear mussels are listed as endangered in Minnesota, Missouri, Wisconsin,[4] Ohio[6][7] and Virginia,[8]: 3  and are considered threatened in Illinois.