Spring Peepers are tiny Chorus Frogs that are about one inch in length when full grown. Their skin coloring can be brown, green, gray, olive, a pale yellow or a pink tone. Spring Peepers can be identified by the "X" markings on their backs and toe pads that help them to climb. They are nocturnal and are rarely seen but easily heard. Their loud high pitched peeps sound like the peeps of young birds. If a person is lucky enough to spot one of these small frogs, the first thing that would most likely catch the person's eyes are the frogs large shiny vocal pouches. When Spring Peepers vocalize, their vocal sacs inflate and deflate as air fills and empties their sacs.