Wood Frog

Key Characteristics: Dark mask on side of head extending backward from the eye; tan to black in coloration; unspotted back

Adults: Wood Frogs are medium-sized brownish frogs with a dark brown ?mask? extending back through the eye and the tympanum to the shoulder, a dark stripe extending forward from the eye to the snout, and a white stripe extending along the upper lip. The ground color varies from grayish-brown, bronze, reddish-brown, to tan. Wood Frogs are usually unmarked dorsally except for some dark spots along the dorsolateral fold and on the sides and dark bands on the upper legs.

Larvae: Wood Frog tadpoles reach up to 4.8 cm in length and are plump with a short, high tail fin. The groundcolor is brownish or olive brown with gold and black speckles. The tail fin is usually lighter and blotched with black. The belly is irredescent white or bronze, and the intestinal coil is visible through the skin.

Eggs: Wood Frog eggs are laid in a large, gelatinous structure containing 500-3,000 eggs and attached near the surface to a submerged substrate. The mass is initially clear or grayish in color, but may turn greenish from the growth of algae.

Distribution: Wood Frogs range further north than any other amphibian in North America. They extend from Labrador south through Georgia and west through the Great Lakes Basin to South Dakota, then north through northern Alaska to the edge of the permafrost.

Habitat: Restricted to fairly large tracts of mesic coniferous, mixed, or deciduous forest where vernal pools are present.

Ecology: Wood Frogs are less aquatic than the other species of Ranids, usually only congregating around water during breeding?for the rest of the year Wood Frogs are solitary woodland animals. They hibernate on land under loose soil, leaf litter, or in decaying logs. Wood frogs are known to undergo a form of cryogenics (freezing) during winter and survive till spring when they thaw out. Their diet consists of terrestrial invertebrates such as beetles, crickets, earthworms, slugs, and spiders. Juveniles may eat a larger percentage of aquatic invertebrates, while tadpoles eat algea, diatoms, and decaying plant and animal matter. They may at times consume larvae and eggs of other amphibians.

Reproduction: The breeding season is protracted (usually lasting only a week or two) and early. Migration by males to the breeding pools typically takes place in late March to early April following the first warm days of spring. Wood Frogs are often in migration when there is still snow on the ground. Females lay eggs in large globular masses, usually attached to a submerged plant stem or twig near the water's surface. Tadpoles develop quickly, usually transforming in May and June.

Voice: A series of explosive clucklike grunts. A distant chorus has been likened to the quacking of ducks or clucking chickens.