Wood Frog

A Wood Frog (Lithobates sylvaticus) is a small North American frog known for its remarkable ability to survive being frozen solid during the winter. They are found across a wide range of habitats, from forests to tundra.

The Wood Frog is a brownish, reddish, or grayish frog with a dark "robber's mask" extending from its eyes to just behind its eardrums. Its underside is a light color. They have smooth skin and can grow to about 2 to 3 inches in length.

The most incredible aspect of the Wood Frog is its natural antifreeze system. During the winter, when temperatures drop below freezing, the frog's heart and breathing stop, and it appears to be dead. It can survive with up to 65% of its body water turned to ice. To prevent cell damage, the frog produces a high concentration of glucose (sugar) in its vital organs. This glucose acts as a cryoprotectant, drawing water out of the cells and into the spaces between them, where it can freeze without harming the cells. When spring arrives, the frog thaws out and its bodily functions resume.

Wood Frogs live in moist woodlands and forests and breed in temporary or vernal pools that are free of fish. They are active during the day, hunting insects, spiders, slugs, and worms. The male Wood Frog has a distinctive call that sounds like a series of short quacks, often heard in early spring as they gather to breed.