Happy start of spring, everybody!
The view outside of the window by my tank is starting to look greener, and my coworkers tell me that the early spring wildflowers are beginning to bloom. That means that it’s time to be on the lookout for my friends, the wood frogs, to start emerging from their winter rest.
Wood frogs are one of the earliest species of frogs to come out in the spring. They are able to do this because of their special physiology. When winter arrives, wood frogs burrow into the leaf litter of forests and meadows, rather than hibernating in the mud underwater like other types of frogs. Since they are very close to the surface, they are exposed to freezing temperatures just like the rest of the plants and animals out in the open.
Normally, this would be a major problem for an amphibian, but wood frogs have a special super-power! They are able to freeze and thaw without the ice damaging their muscles and organs. A special antifreeze-like chemical protects their heart and lungs, but up to 65% of the water in the rest of the body will freeze solid! When the temperatures start to rise again with spring, they are able to quickly thaw out and become active faster than other amphibians, who are still buried beneath cold waterways.
You can identify them by their pale brown color, with a dark mask-like stripe from their nose to their eyes. However, the best way to find them is often to follow your ears! The males make loud quacking sounds during the breeding season to attract mates, and these calls can be heard from quite a distance (check out our video below).
Their preferred habitat is forests and other wooded areas, as well as marshes and meadows. Here in the park, we often see wood frogs in the Beech Forest and Frog Pond. They love to lay their eggs in small seasonally-flooded areas called vernal pools. In fact, my coworkers have been working hard to improve habitat for wood frogs in the park by building them new vernal pools for breeding. You can spot one new pool currently under construction next to the millrace by the dam.
If you are out in the park and see or hear a wood frog, be sure to stop by the Visitor Center to let my coworkers know! They keep track of the number of breeding frogs every year to make sure the population is healthy and stable.