Wood Frog
The wood frog has a distinct dark "mask" behind each eye.
About This Species
Wood frogs vary greatly in color, with females more brightly colored than males. Wood frogs are able to survive winters by freezing themselves. While their hearts stop beating and they no longer breathe, their cells do not freeze as this would be fatal, but ice does form between their cells. In the spring, they thaw and resume their normal behaviors. Wood frogs are the only frogs that can be found north of the arctic circle.
More Information:
Physical Characteristics
Dark “mask” on each side of face; ridge along each side of back; hind toes webbed; usually a light stripe along middle of back; skin relatively smooth; head and body length up to about 83 mm (3.3 inches).
Mature Male
Base of innermost toe on front feet swollen; averages slightly smaller and darker than adult female; expanded vocal sacs, one on each side, extend above front legs.
Range
Mountains surrounding North Park; upper tributaries of the Colorado River in Grand County; upper Laramie River drainage in Larimer County. Mainly at elevations of 7,900-9,800 feet. Locally fairly common in suitable habitat.
Habitat
Subalpine zone, in marshes, bogs, pothole ponds, beaver ponds, lakes, stream borders, wet meadows, willow thickets, and forests (lodgepole pine, spruce, fir, or aspen) bordering these habitats.
Reproduction
Breeding Call
A rapid series of 1–8 (usually 3–5) rough clacking notes (a chorus sounds somewhat like a group of softly quacking domestic ducks).
Larvae
Upper side with blackish and olive-gray pigment; sides shiny bronze or pinkish; eyes high on head; tail fin high, strongly arched on top, with dark spots and blotches; usually 2-3 rows od tiny teeth on upper lip, 3-4 rows on lower lip; up to about 52 mm (2 inches) long.
Eggs
Deposited in large globular masses about the size of a baseball or tennis ball and usually including several hundred eggs; usually attached to sedges in shallow water, often on north side of pond.
Life History
Breeds in shallow ponds, mainly in May-June. Breeding ponds often contain thick sedges and may dry up in summer. Larvae metamorphose into small frogs usually in July and August.