North American Wood Frog Habitats Are Also North of the Arctic Circle

Summary: North American wood frog habitats are also north of the Arctic Circle, along which wood frogs abide as only tetrapods at 66°33′49.2″ north of the Equator.

wood frog (Lithobates sylvaticus): Savannah River Ecology Laboratory (SREL)/John D. Willson, via USGS Amphibian Research and Monitoring Initiative (ARMI)

North American wood frog habitats are also north of the Arctic Circle, where wood frogs abide as only cold-blooded tetrapods (from Greek τετρα-, “four” and ποδός, “foot’s, leg’s”) at 66°33′49.2″ N latitude.

The Anura (from Latin an-, “not” and Greek - οὐρά, “tail”) amphibian order member of the Tetrapoda superclass bears the common name wood frog as forest-loving. The Ranidae (from Latin rāna, “frog” and from Greek -ειδής, “-like” via Latin -idæ) true-frog family member claims as scientific names Lithobates sylvaticus and Rana sylvatica. John Eatton Le Conte, Jr. (Feb. 22, 1784-Nov. 21, 1860) in 1825 scientifically described Rana sylvatica (from Latin silva, “forest” and -āticus, “regarding” via silvāticus) specimens.

Three- to 5-year wood frog lifespans expect marshy, treeless taigas and tundras northwards; moist, hilly and mountainous woodlands eastwards; and open grasslands and wet meadows westwards.

Georgia northward through Newfoundland and Labrador and westward through Oklahoma, Colorado northward through Northwest Territories, Montana northwestward through Yukon Territories and everything in-between favor wood frogs.

Fish-free, seasonal or semi-permanent water bodies in 3 Canadian territories, 10 Canadian provinces and one Unitedstatesian federal district and 35 Unitedstatesian states guard wood frog-breedable habitats. January through April herald breeding-season months despite adult-preying garter, ribbon and water snakes; herons; mink; raccoons; skunks and tadpole-preying diving beetles, leeches, newts, salamanders and waterbugs. Freezing temperatures infrequently imperil breeding in response to physically and sexually mature 1- to 2-year-old males cackling duck-like, rolling, soft, serialized ca-ha-ha-ac, ca-ha-ha-ac, ca-ha-ha-ac advertisement calls.

Batrachochytrium dendrobatidis fungal disease, fertilizer runoff, globally warmed climate change, nonnative species, toxic pesticides, trematode fluke-induced deformities and ultraviolet radiation jeopardize North American wood frog habitats.

Physically and sexually mature 2- to 3-year-old females keep their close-fitting, globular, 10- to 13-centimeter (3.94- to 5.12-inch) diameter, 1,000- to 3,000-egg masses attached or free-standing.

Small green algae in jelly loped around each egg leave egg masses looking green like their aquatic-plant attachments and like shallow pond and pool surface waters. Nine- to 30-day-old eggs mature into tadpoles maintained initially, temporarily by their nutritious yolk sac and measuring 42 to 48 millimeters (1.65 to 1.89 inches) long. Tadpoles need algae, organic debris, plant tissue and suspended matter even as beetles, caterpillars, crickets, flies, mosquitoes, moths, pillbugs, sowbugs, spiders, stinkbugs and worms nourish adults.

North American wood frog habitats offer season's coldest temperatures, north to southward, from minus 60 to 5 degrees Fahrenheit (minus 51.1 to minus 15 degrees Celsius).

Metamorphosis produces juvenile wood frogs, who peregrinate in their adult periods to 83.6-square-meter (899.86-square-foot) home ranges from 50- to 60-millimeter- (1.97- to 2.36-inch-) long, two-month-old tadpoles.

Lang Elliott, Carl Gerhardt and Carlos Davidson quantify 1.375- to 3.25-inch (3.49- to 8.25-centimeter) snout-vent (excrementary opening) lengths in The Frogs and Toads of North America. Adults reveal black-brown, brown, copper or tan bodies darkly masked from their snouts, through gold-rimmed dark eyes to eardrums, prominent dorsolatral (back-to-side) folds and yellow-tinged abdomens. Fallen logs and leaf litter in wooded ravines shelter female and male, juvenile and mature Lithobates (from Greek λίθος, “stone” and βάτης, “I tread”) overwintering populations.

Brown, copper, pink-brown or tan bodies with dark masks, dorsolateral folds and yellow underparts trademark antifreeze-like cryoprotectants and duck-like quacks for North American wood frog habitats.

range map for wood frog (Lithobates sylvaticus): U.S. Geological Survey, Public Domain, via Wikimedia Commons

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

A light stripe on the upper jaw and a brown-black mask across the eyes from snout back to below the tympanum (external hearing structure) characterize wood frogs (Lithobates sylvaticus); Islesboro Island, Waldo County, south central Maine: Savannah River Ecology Laboratory (SREL)/John D. Willson, via USGS Amphibian Research and Monitoring Initiative (ARMI) @ https://armi.usgs.gov/gallery/result.php?search=Lithobates+sylvaticus

range map for wood frog (Lithobates sylvaticus): U.S. Geological Survey, Public Domain, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Rana-sylvatica_Range.gif?uselang=fr

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