Spring peeper. Photo by David Preston
Spring Peeper
Pseudacris crucifer
Cool fact: Spring peepers survive the winter by becoming dormant under leaf litter and under logs, relying on the same sugars they use as nutrients to also serve as a kind of natural “antifreeze” that keeps the tiny frogs safe to temperatures around six degrees below zero.
The northern spring peeper became Maine’s Official State Amphibian in 2025, so what better creature to highlight? It is one of only two tree-dwelling frogs in Maine, the other being the gray tree frog.
You may know the spring peeper as a tell-tale sign of spring in Maine, as their chorus harkens from moist forest areas and fields near ponds, streams, or swamps, a joyful noise to the human ear after months of dormancy. In Maine, expect to hear their chorus again within a few weeks of the spring equinox.
Northern peepers are a woodland species that live in the eastern half of North America, from Florida to Canada and west to Minnesota and eastern Texas.
Their skin is smooth and varies in shades of gray, green, tan, or brown; their bellies are cream-colored or grayish white. Further identifying them is a dark “X” pattern on their backs, and bands on their legs and face. An adult male is less than an inch in length; the female, about 40% larger. Their weight averages from 0.11 to 0.18 ounces, so they can easily fit on the end of your finger!
Like most amphibians, they have slightly enlarged toe pads with glands that secrete a mucus that acts as an adhesive for better gripping ability on various surfaces. Although good climbers, they spend most of their time on the ground, often hiding under leaf litter during the day. While they typically remain among vegetation along the water’s edge, they are excellent swimmers thanks to webbed hind feet.
Spring peepers belong to a group known as “chorus frogs.” Males have dark wrinkles of extra skin on their throats, that expands when calling. The peeps are produced when they close their nostrils and force air from their lungs over their vocal cords. The sound is amplified by an air sac almost the length of the frog’s body that expands under the throat, letting the sound resonate.
The timing of breeding depends on temperatures, but generally begins in late February or March and continues into May. Spring peepers are known for the males’ mating call: a high-pitched whistling or peeping sound repeated about 20 times a minute. The faster and louder they sing, the greater the chances of attracting a mate. As dusk arrives, males gather near water in search of a mate and will often sing in trios, with the deepest-voiced frog starting the call.
Small groups will coordinate and alternate their calls, so that females can hear and evaluate each one. (A frog’s version of The Dating Game?)
Unlike many other frog species, spring peepers lay their eggs singly, rather than in a mass. Females lay their eggs in vernal pools, ponds, and other wetlands where fish are not present, offering a higher survival rate of their offspring. She may lay from 750 to 1,200 eggs, which attach to submerged aquatic vegetation. Males fertilize the eggs as they are laid; they can hatch within two days to two weeks, depending on temperature. The tadpoles have gills for breathing under water and tails to help them swim, but over 6 to 12 weeks they transform into frogs, losing their tails and using their lungs as they move onto land for the rest of their lives. Spring peepers are said to have short lives, living three to four years at most.
Adults eat a variety of foods, including beetles, flies, ants, spiders, and snails, and play a signifi- cant role in controlling insect populations. Tadpoles consume tiny eggs, algae, and microbes in the water. Spring peepers are on the menu for large carnivorous insects, salamanders, snakes, skunks, raccoons, and many types of birds; tadpoles are also eaten by aquatic invertebrates and salamander larvae.
Thanks to efforts to preserve wetland environments and clean water, the peeper population in Maine seems stable and distribution is widespread. As with many other wildlife species, loss of habitat does pose a threat.
If you’re interested in helping spring peepers and other amphibians cross roads safely during their nighttime migrations, check out how to participate in a Maine Big Night. Maine Audubon is a Big Night host; to request a kit, email naturalist@maineaudubon.org.
In addition, if you’d like to share your photo-documented observations, please consider sharing them with the Maine Amphibian & Reptile Atlas Project (MARAP).
More “Cool Facts”
- Spring peepers hibernate during the winter in soft mud near ponds, under logs, and in holes or loose bark in trees. They have a natural glucose “antifreeze” in their blood to help them survive cold temperatures; up to 70% of their body can freeze — even the heart stops pumping! Their metabolism drops to minimal activity and they can survive months without food intake. Due to this ability to survive frigid temperatures for long periods of time, peepers are believed to have been one of the first amphibians to move north after the last ice age.
- Pseudacris means “false locust” and comes from their high-pitched calls being confused with insect sounds. Crucifer is from the cross or X on their backs; other chorus frogs have spotted or striped markings.
- Males can peep 3,000-4,000 times per hour for several hours, adding up to 13,500 peeps per night. Their calls can be heard up to two miles away!
- Smaller “satellite” males take advantage of group vocals: they wait near a loud, fast-peeping male, and when a female responds to the call, the satellite frog attempts to intercept her before the singing male has a chance.
- Peepers are able to make themselves lighter or darker to better match their surroundings, e.g., when moving from dry to wet leaves, full sun to shade, or climbing from the shady forest to bright green.
- Sensitive skin makes spring peepers good indicators of environmental health.
Written by Jayne Winters – March 25, 2026
Resources:
https://www.nwf.org/Educational-Resources/Wildlife-Guide/Amphibians/Spring-Peeper
https://extension.umaine.edu/signs-of-the-seasons/indicator-species/spring-peeper-fact-sheet/
https://natureformysoul.com/2014/03/10-things-you-didnt-know-about-spring-peepers/
https://maineaudubon.org/news/small-wonders-how-to-be-a-spring-peeper/
https://hhltmaine.org/11123/nature-notes-spring-peepers/
