Vernal Pools: Woodland Nurseries for Frogs and Salamanders

This past weekend, I went hiking with my family in Harriman State Park in New York. We’ve had a very wet spring—well, actually it sometimes seems as if we’ve been living in a rainforest. It’s possible that all this rain will means lots of frogs and toads this summer.

While hiking we found a swamp and listened to a wonderful chorus of spring peepers and (we think) Eastern American toads.

My son Jeremy listening to a chorus of spring peers, Surebridge Swamp, Harriman State Park, New York

My son Jeremy listening to a chorus of spring peepers, Surebridge Swamp, Harriman State Park, New York

We also saw lots of vernal pools, bodies of water that appear in the spring and last from two to three months before they dry up in the summer. Some types of amphibians, crustaceans, and other wildlife need these pools for breeding, hatching eggs, or as a nursery while they are young. Because they are temporary, vernal pools do not contain fish (which eat tadpoles and larvae).

When you hike by vernal pools, they don’t look like much. In fact, my sneakers got soaked as I tried to jump over one. Yet they are of critical importance to wildlife. I’ve noticed, however, a lot of comments on environmental blogs that read something like this, “Only treehuggers would want to save these mud puddles!” Yet wood frogs, some species of salamander, and fairy shrimp need these “mud puddles” in order to survive. Every year hundreds of acres of wetlands are lost (usually forever) to commercial or residential development. According to the Ohio Vernal Pool Partnership

These usually small, but very dynamic wetlands fill with water, blossom with life and host a cacophony of sounds and a plethora of life forms every spring, only to disappear into the forest floor every autumn…. A vernal pool is a place where a good naturalist can weave many fascinating stories about the amazing life forms, adaptations, and life histories of its inhabitants, and demonstrate it by a single swoop of a dip net! Vernal pool is a miniature, fascinatingly complex and fragile world, with all of its drama played out every year close to our homes, and yet most of us have never witnessed it. [Ohio Vernal Pool Partnership].

Salamanders and woodfrogs migrate from their wintering sites to vernal pools for breeding when the conditions are right, courtesy of The Vernal Pool Association
Salamanders and woodfrogs migrate from their wintering sites to vernal pools for breeding when the conditions are right, courtesy of The Vernal Pool Association

Here are some sites and articles I’ve found (you can also try putting “vernal pool” and the name of your state in google).




New Jersey

Massachusetts (The Vernal Pool Association)



Winter Turns Frogs into Frogsicles

This past Sunday, my husband and I went for long hike in Harriman State Park in New York. In late March and early April, the sound of the spring peepers is deafening. But the other day we heard only one or two peepers. I did a little research to find out what happens to the peepers in the fall and winter. What exactly do they do from now until early spring?

Wood Frog

Wood Frog

Frogs and toads have evolved strategies to survive freezing temperatures. Wood frogs and spring peepers actually become a “frogsicle,” as Larry Lyons explains in his article, “All the Frogs Will Soon be Frogsicles” in the Niles (MI) Daily Star. The frogs will soon find a place under the leaf litter or in a crack in a log or rock to settle for their winter nap. They’ll slowly begin to freeze as soon as temperatures reach the freezing point. The frog’s blood stops flowing, its lungs, heart and muscles stop functioning, and ice fills the body cavity. As Niles writes, “We now have a frogsicle in suspended animation.”

About 65% of the frog is frozen. It manufactures large amounts of blood sugar that serve as anti-freeze, preventing ice damage to its organs. When spring temperatures are consistently above freezing, they begin to thaw out and break out in a chorus of frog calls (as mating season begins).

What about other frogs and toads? Toads dig a burrow under the frost line, where they go into a mild state of hibernation. Their metabolism slows down and they no longer need food or water. Aquatic frogs such as green frogs go into what’s called a state of torpor. They descend to oxygen rich deep water, find a hiding place, and don’t move around much until the spring comes.

Perhaps we are more like animals than we care to admit. I know I slow down in late fall and hibernate until spring!