These days, even the smallest things can take on greater significance. Like many of you, I’ve been in quarantine for weeks now, except to take occasional walks outdoors. And so it happened that last week, while hiking along Maryland’s C & O canal, I encountered a high-pitched sound. The single, repeated note seemed to be emanating from the forest.
Rounding a corner, I discovered the source- a shallow pool, colored neon green with algae. Leaning in, I could just make out a few voices. I had stumbled upon a chorus of spring peepers singing to their potential mates.
The Spring Peeper World
Spring peepers, or Pseudacris crucifer, are chorus frogs. They are the smallest frogs in the Chesapeake Bay area and one of the earliest to call and breed. Due to their high-pitched song, they are often confused with locusts. This explains the first part of their scientific name, pseudacris, which is derived from the Greek pseudes meaning ‘false’ and akris meaning ‘locust.’
The second part of the name, crucifer, refers to the distinctive cross-like pattern that the spring peeper bears on its back.
Spring peepers have a cross on their back/Photo: Steve Byland for shutterstock
At just under one inch and weighing less than a quarter-ounce, this tiny frog is easy to miss. Moreover, its drab gray-brown/olive color helps it blend in with its surroundings. But for what it may lack in size, the spring peeper more than makes up for in vocals. In early spring, its chirping call is so loud it can be heard for up to two miles.
How The Peep Show Works
So how does such a tiny animal make so much noise? Like all calling frogs, the male produces the sound by inflating a vocal sac located under his chin. Accomplishing this takes tremendous effort for the spring peeper, though, for when fully expanded, the sac is almost as big as he is.
Photo: Brian Lasenby for shutterstock
And these frogs can go on for hours. During breeding season, males typically gather at small pools by the hundreds to start their chorus. After establishing their territory, they begin calling, emitting a shrill peep once every second. The faster and louder a male sings, the better his chances for attracting a mate.
Sometimes, in order to boost the volume, males will even form trios (which also causes them to compete.) Females, however, typically choose mates by the quality of their individual song. This can vary depending on genetics, size and age, all of which can greatly affect the frequency of a male’s calling.
You can expect the volume to further increase following a spring rain when more males tend to congregate. Sometimes, however, an unexpected freeze can shut the show down for a while. That being said, spring peepers produce large quantities of glucose that act as a natural anti-freeze. This allows most of them to thaw back out and resume their song once temperatures warm up again.
This same quality also allows the frogs to effectively ‘freeze’ themselves to hibernate during the winter.
Spring peeper hiding in fall foliage
Spring peeper season lasts approximately from March through April. Once breeding season is over, peepers move into woodlands and other shrubby areas.