Wood frogs are the only frogs that are found north of the Arctic Circle. Discover facts about wood frogs with information from a published biologist in this free video on frogs and amphibians.
Here we have a wood frog, we have two wood frogs. Their scientific name is lithobates sylvaticus. They have a broad North American distribution, extending from the southern Appalachians to the arctic tree line. This particular species is very interesting, as it's found further north than any other North American reptile or amphibian. They are the only frogs that are found north of the Arctic Circle. This frog is very common in woodlands across the range. They are most common in the summer under stones, stumps, and leaf litter. This frog can reach lengths of two and a half inches to three inches. And the females are generally a lot larger than the males. You can see that they are often brown, tan or rust colored, and the underparts of this frog are often yellowish and their legs are generally green. They are characterized by a black line along the side of their eyes, and that extends to the back of their head. These wood frogs are seasonal breeders, and they begin very early in spring. They are often the first frogs to begin calling at the ponds, even before the ice is completely melted. The females can lay large globular egg masses in the deepest part of the ponds, of about one thousand to three thousand eggs. The jelly around the eggs become camouflaged in this green color which is actually produced by algae in the pond. The tadpoles of this species undergo a complete metamorphosis in about two months and they can reach sexual maturity in approximately two years. The wood frog tadpoles are very cool 'cause they actually have been shown to have the strongest powers of kin recognition within amphibian larvae. They've been documented by marking them with dye and releasing them into natural habitats, and it's been shown that they are able to aggregate back together with the larvae from their egg mass, and it's believed that they do this because it allows them the potential benefits of food, thermoregulation, and defense against other predators. These wood frogs are insectivores. They like to eat slugs, snails, and various insects they find on the forest floor. The wood frog is actually very interesting, as they are resistant to freezing during the winter time. This particular species of frog can convert, uses its liver glycogen and it converts it into large quantities of glucose in response to ice formation in their tissues. The glucose that they make acts as an antifreeze inhibiting ice formation and the rupturing of their cells. If the ice formation is confined to extracellular fluids, then they can survive the winter.