Tuesday, April 7, 2015

Spring Peepers

A Northern Spring Peeper

      Northern Spring Peepers (Pseudacris crucifer formerly Hyla crucifer) are among our smallest frogs. These tiny treefrogs only get to 1.5 inches when full grown. The males are even smaller, not even making it to that size. They may be small, but they sure do make some loud calls. Some say they're all "peep" and many consider their calls synonymous with Spring.
     Like most frogs, only the males call, forming a large chorus who's sound can carry for quite a distance. I recall one particular night long ago (one of the legendary "big nights" that herpetology fanatics always talk about when all the environmental conditions are perfect resulting in huge numbers of amphibians coming out to breed) quite well. The Peepers were so loud that I had to yell in order for my future wife to hear me, though we were barely twenty feet apart. When we left that night, the sound had been so deafening that our ears rang for an hour after leaving the swamp. Unfortunately, though I've seen some other "big nights," I've never heard that many treefrogs (and toads and even wood frogs that evening) calling at once again.
     Outside the breeding season though, Peepers are rarely seen or heard. They have excellent camouflage and can actually change color to some degree. This makes the often cited "X" field mark on their backs sometimes difficult to discern. Since they can climb into low foliage as well as hide under the leaves, they have numerous places to hide their small selves.

A pair of Spring Peepers in amplexus.

      Mating takes place in typical frog fashion: with the smaller male on top of the female in a mating position termed "amplexus." The females usually lay their eggs singly or in small batches attached to underwater objects. The eggs are tiny (though they can lay 22-1200 eggs per female) and so the resulting tadpoles are small as well. They metamorphose 45-90 days later and leave the pond or vernal pool they were using, sometimes traveling a fair distance from water.

Peepers normally lay a single egg or a small batch, but this one laid several of them together because it was in captivity with limited options on where to lay them. 

Spring Peeper tadpoles are small indeed.

     Spring Peepers are also remarkably cold tolerant, being able to survive even if portions of their bodies freeze due to production of high glucose levels in their blood system. These treefrogs often will overwinter under leaf cover, but usually above the frost line. Though known for calling in the early Spring, males sometimes get confused by the similar length days and temperatures of the Fall and will occasionally call then as well. This is sometimes referred to as the "fall echo."

A male Northern Spring Peeper calling.
     To me, the sound of a Spring Peeper chorus is one of the true signs of spring. Though I enjoy spring wild flowers and creatures, these tiny frogs embody the essence of spring for me. They will soon be quiet however, so get out to enjoy them now while you still can. Just in case though, I have a short video of a male Peeper calling from the Capital Naturalist YouTube Channel. Check it out at:


  1. Just this week, I've reread the page in your book on spring peepers. It's my go-to guide on local herps. Thank you for the update.

  2. Thanks for all the information on peepers- definitely one of my all time favorites!

  3. I have been hearing a bit of the "fall echo" from peepers this week in Reston, VA.