Spring Peepers Alert us to Beginning of the Season

by Crystal Cockman

February 16, 2016

Though you wouldn’t know it from the freezing rain we had this week, spring is on its way. One signal of this is the emergence of spring peepers (Pseudacris crucifer). Spring peepers are a small chorus frog found in the eastern United States and Canada. They are easy to identify as they have a distinctive cross marking an X on their backs. Their overall body coloration can vary with temperature and other surrounding conditions, from brown to grey to even red or yellow. A small frog, they grow to only about 1.5 inches in length.

There are two subspecies of spring peeper, the Northern and Southern. Northerns can be found all across the eastern U.S. and Canada, whereas southerns are only found on the southern Gulf Coast from Texas to Florida north into Georgia. Southerns can be distinguished from northerns by their darkly speckled bellies. Spring peepers are found throughout most of North Carolina, but not on the outer banks. They prefer marshy woodlands near ponds and wetlands.

Spring peepers are most active at nighttime when they feed on small insects and arthropods, including ants, beetles, caterpillars, and spiders. They help control populations of these species. They are also food for a variety of other species, including snakes, fish, larger frogs, and birds.

As their name implies, the call of a spring peeper sounds much like a young chick. Only the males call, and they are calling for a mate, typically at the edge of a pond or wetland. Their loud high-pitched calls can be heard up to over a mile away. Females lay up to 1000 eggs in clusters, typically attached to submerged vegetation. Tadpoles emerge after 10 days or so, and metamorphose into frogs around 2 to 3 months later.

They are able to withstand some very cold temperatures by a unique adaptation. The onset of freezing temperatures triggers an overproduction of glucose or glycerol that protects them against the cold. Water from organs is transmitted to other body spaces, which reduces damage by freezing. By these methods, they are able to hibernate below the forest floor and withstand body temperatures up to -8 degrees Celsius.

Spring peepers are common and widespread, with an estimated population of millions of individuals. Loss of wetlands has contributed to their decline in certain areas; however, and they are listed as threatened in the states of Iowa and Kansas. By helping control the pest population, including mosquitos, spring peepers provide a benefit to humans, and preserving their habitat is an important way to keep the species and related benefits around.