Lithobates sylvaticus or Rana sylvatica, commonly known as the wood frog, is a frog species that has a broad distribution over North America, extending from the boreal forest of the north to the southern Appalachians, with several notable disjunct populations including lowland eastern North Carolina. The wood frog has garnered attention from biologists because of its freeze tolerance, relatively great degree of terrestrialism (for a ranid), interesting habitat associations (peat bogs, vernal pools, uplands), and relatively long-range movements. The ecology and conservation of the wood frog has attracted research attention in recent years because they are often considered "obligate" breeders in ephemeral wetlands (sometimes called "vernal pools"), which are themselves more imperiled than the species that breed in them. The wood frog has been proposed to be the official state amphibian of New York. Wood frogs range from in length. Females are larger than males. Adult wood frogs are usually brown, tan, or rust-colored, and usually have a dark eye mask. Individual frogs are capable of varying their color; Conant (1958) depicts one individual which was light brown and dark brown at different times. The underparts of wood frogs are pale with a yellow or green cast; in northern populations, the belly may be faintly mottled. Their body colour may change seasonally; exposure to sunlight causes darkening. The contiguous wood frog range is from northern Georgia and northeastern Canada in the east to Alaska and southern British Columbia in the west. It is the most widely distributed frog in Alaska. It is also found in the Medicine Bow National Forest. Wood frogs are forest-dwelling organisms that breed primarily in ephemeral, freshwater wetlands: woodland vernal pools. Long-distance migration plays an important role in their life history. Individual wood frogs range widely (hundreds of metres) among their breeding pools and neighboring freshwater swamps, cool-moist ravines, and/or upland habitats.