What the robin is to lawn and meadow, the peeper is to the wooded swamp. The first robin usually appears on a bright, though still chilly day, hopping over a bit of dry yellow grass revealed by the retreating snow. The peeper comes to us as a distant chorus on the first evening a light coat or sweatshirt will suffice, or all of a sudden when, on a night warm enough to crack a car window, we pass a bit of low ground flooded by the spring rains and snowmelt.
They’re more often heard than seen. Approach them, and the song cuts off well before you can get near. Peepers are skittish. You would be too if you were very small and made a sound that could be heard a mile away.
Nevertheless, they have some remarkable abilities.
They can survive being frozen.
Let’s start with their most amazing feat: the ability to awaken after freezing solid.
Most frogs bury themselves in mud to keep their body temperatures above freezing. Not the peeper. It hibernates under leaf litter and logs. When temperatures dip below freezing, the frog’s liver begins to flood the blood stream with massive amounts of glucose, which prevents cell damage even when most of its body is frozen. During this time, the frog’s heart stops beating and it appears dead. But the clock is ticking: One study found 85 percent of frogs survived three days in the state, while 50 percent survived for a week.
Why do they do it? Why not find a better place to wait out the winter where they won’t freeze? Because there’s an advantage to cold tolerance: it lets the peepers emerge early in the spring before predators get their bearings.
So next time you hear the peepers calling, think about how it’s only possible because those little frogs were able to withstand becoming ice cubes several times over the previous winter.
Small body, big sound.
Peepers are .8-1.5 inches long and weigh 3-5 grams. But for an animal the size of a matchstick and weight of a nickel, they can make a racket – up to 104db when they get together, which is comparable to a chainsaw. The male peeper generates his seductive and ear-splitting peep by closing his nostrils, and pushing air over his vocal chords into the throat sac, which acts as a resonator.
An article in Wired magazine analyzed the peepers’ calls and found they consistently hit a specific note – around 3000 hz, equivalent to G7, the highest G on a piano. Call rate ranges from around 20 to 90 per minute, and frequency turns out to be important. Females go for males that call frequently and loudly because it advertises fitness. According to the article: “To chirp faster, a frog has to take in more oxygen, and consume more energy. The frogs that chirp the fastest are the ones with the greatest stamina. Like the fastest long distance runners, they’re able to sustain a high consumption of energy over a long duration.”
On the move
Like many amphibians, the spring peeper breeds in temporary ponds formed by snow melt and spring rains called vernal pools. Each year, amphibians make a pilgrimage to these pools, usually on the first warm, rainy night.
Locally, many peepers made the move weeks ago during warmer weather, though not all.
Each year, locals volunteer to help amphibians cross roads. For a sense of how dangerous the trek is, here are some numbers from a recent night, reported to the DEC by local volunteers.
- wood frog (280/66)
- spring peeper (219/234)
- eastern newt (25/54)
- spotted salamander (23/8)
- Jefferson-blue spotted salamander complex (14/0)
- four-toed salamander (8/1)
- pickerel frog (1/0)
- American toad (1/0)
Interested in volunteering to help? Here’s the DEC page.
X marks the spot
The “X” marking on the frog’s back is one of easiest ways to distinguish it from other small frogs. That marking, combined with its call, is responsible for its Latin name: pseudacris crucifer, which means “cross-bearing false locust,” the latter a reference to its insect-like call.
If “crucifer” sounds familiar, it’s because it rhymes with Lucifer. The first the cross-bearer, the second the light-bearer (or bringer). It’s quite biblical, which is appropriate for a frog who begins to call around Easter.
Peepers call in a given location for 4-8 weeks; breeding season stretches from March to June. After mating, the female lays 800-1000 eggs underwater.
The eggs hatch in 6-12 days; tadpoles mature in 45-100 days, quicker in temporary pools.
Sexual maturity: 3 years.
Active: Mostly nocturnal, but sometimes active during the day in more shaded areas.
Adult: Spiders, ants, beetles; tadpole/larvae: algae and other aquatic organisms.
Is eaten by
Adult: Larger frogs, snakes, skunks, owls, other birds; tadpole/larvae: diving beetle, leeches, dragonfly larvae.