senter2080.JPG | New England Freelance Photographer Cheryl Senter

Grafton, NH: Tuesday, June 10, 2014: Wood frogs mating in a small pond.<br />
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The wood frog (Lithobates sylvaticus) has a broad distribution over North America, extending from the southern Appalachians to the boreal forest with several notable disjunct populations including lowland eastern North Carolina. The wood frog has garnered attention by biologists over the last century 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 a great deal of research attention in recent years. This may be because they are often considered "obligate" breeders in ephemeral wetlands (sometimes called "vernal pools") that are themselves more imperiled than the species that breed in them. The wood frog is the state amphibian of New York.<br />
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Similar to other northern frogs that hibernate close to the surface in soil and/or leaf litter, wood frogs can tolerate the freezing of their blood and other tissues. Urea is accumulated in tissues in preparation for overwintering, and liver glycogen is converted in large quantities to glucose in response to internal ice formation. Both urea and glucose act as "cryoprotectants" to limit the amount of ice that forms and to reduce osmotic shrinkage of cells. Frogs can survive many freeze/thaw events during winter if no more than about 65% of the total body water freezes. Lithobates sylvaticus primarily breeds in ephemeral pools rather than permanent water bodies such as ponds or lakes. This is believed to provide some protection of the adult frogs and their offspring (eggs and tadpoles) from predation by fish and other predators of permanent water bodies. Adult wood frogs emerge from hibernation in early spring and migrate to nearby pools. There, males chorus, emitting duck-like quacking sounds. A male approaches a female and clasps her behind her forearms

Grafton, NH: Tuesday, June 10, 2014: Wood frogs mating in a small pond.

The wood frog (Lithobates sylvaticus) has a broad distribution over North America, extending from the southern Appalachians to the boreal forest with several notable disjunct populations including lowland eastern North Carolina. The wood frog has garnered attention by biologists over the last century 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 a great deal of research attention in recent years. This may be because they are often considered "obligate" breeders in ephemeral wetlands (sometimes called "vernal pools") that are themselves more imperiled than the species that breed in them. The wood frog is the state amphibian of New York.

Similar to other northern frogs that hibernate close to the surface in soil and/or leaf litter, wood frogs can tolerate the freezing of their blood and other tissues. Urea is accumulated in tissues in preparation for overwintering, and liver glycogen is converted in large quantities to glucose in response to internal ice formation. Both urea and glucose act as "cryoprotectants" to limit the amount of ice that forms and to reduce osmotic shrinkage of cells. Frogs can survive many freeze/thaw events during winter if no more than about 65% of the total body water freezes. Lithobates sylvaticus primarily breeds in ephemeral pools rather than permanent water bodies such as ponds or lakes. This is believed to provide some protection of the adult frogs and their offspring (eggs and tadpoles) from predation by fish and other predators of permanent water bodies. Adult wood frogs emerge from hibernation in early spring and migrate to nearby pools. There, males chorus, emitting duck-like quacking sounds. A male approaches a female and clasps her behind her forearms
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