Pickerel frogs emerge early in spring from their muddy, pond-bottom hibernacula. They mate in April and May in the Northeast, and males call to attract females for four to six weeks. The calls resonate inside their internal vocal sacs located between their tympanum (eardrum) and foreleg, unlike spring peepers and American toads, whose vocal sacs are located directly under their mouths. Pickerel frog calls resemble short “snores,” which last a second or two. The call is similar to the sound made by running your thumb across a comb’s teeth. Pickerel frogs call from underwater as well as on top of mounds of vegetation.