The spring peeper is Michigan's smallest frog (0.75 - 1.38 in. long) but is also the loudest. Peepers are found in brushy and woodland ponds and call most energetically at night. They can be distinguished from the western chorus frog by the x-shaped mark on the back.

The spring peeper "peeps" or jingles. When they are in full chorus, the sound can be unbearably loud and make it difficult to distinguish any other species, especially the western chorus frog.