Pickerel Frogs: Night Eyes on Folded, Spotted, Toxic Tan Bodies

Summary: North American pickerel frog habitats get day-active eyes on tan bodies with brown-spotted rows and orange-yellow inner thighs in eastern wooded wetlands.

pickerel frog (Lithobates palustris; formerly Rana palustris); Leesylvania State Park, Woodbridge, Prince William County, Northern Virginia; Sept. 2, 2012: Judy Gallagher (judygva), CC BY 2.0, via Flickr

North American pickerel frog habitats accomplish distribution ranges from Nova Scotia through Georgia, Alabama through Louisiana, Texas through Kansas, Missouri through Minnesota, Wisconsin through Maine, Ontario through New Brunswick and everywhere in-between.

Pickerel frogs bear their common name as bait for American, chain, grass, muskellunge, northern and redfin pickerel fish and as true frogs in the Ranidae family. The scientific names Lithobates palustris and Rana palustris carry the respective English equivalents of "haunter of (climber over, treader upon) stones in marshes" and "marsh frog." Scientific designations defer to descriptions in 1825 by John Eatton Le Conte (Feb. 22, 1784-Nov. 21, 1860), United States Army Corps of Topographical Engineers officer, 1818-1831.

Pickerel frog life cycles expect twilight zones of caves near clear, cool, northerly waters and tannin-stained, warmer, southerly floodplain swamps in woodland pools, ponds and springs.

December through June favor pickerel frog life cycles with breeding season months despite predatory bald eagles, garter, ribbon and water snakes, insects, mink, newts and raccoons.

Pickerel frogs get around in water and on land through front toes without terrestrial life-unfriendly webbing that gives space for male swollen thumbs during mating seasons. Matched filtering helps them hear, despite mixed-species choruses, by calls having frequency ranges that vibrate two circular tympanic-membraned eardrums and the inner-ear's amphibian and basilar papillae. Closed-mouth, closed-nostril advertisement, similar courtship and rain, aggression and similar release calls involve lung expirations that impel air streams over vocal cords and inflate vocal sacs.

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

Two thousand to 4,000-egg clusters and, 11 to 21 days later, gill-breathing, keel-tailed tadpoles keep to water whereas legged, lung-breathing, tailless adults know land and water.

Multicolored masses 1.97 to 3.4 inches (5 to 10 centimeters) in diameter latched brown-topped, cream-bottomed, spherical eggs onto aquatic vegetation at surface to 4-foot (1.22-meter) depths. Yellow to yellow-brown tadpoles, with eyes close together and pointed snouts, mature within about three months to cream-bottomed, four-legged, gray brown-topped, 1.02-inch (2.6-centimeter-) long, olive-brown metamorphs. Unlike algae-, debris-, diatom-eating tadpoles, adults need ants, beetles, caddisflies, craneflies, crickets, flies, grasshoppers, mites, mosquitoes, moths, pillbugs, sowbugs, spiders, springtails, stinkbugs, termites, wasps and worms.

North American pickerel frog habitats offer season's coldest temperatures, northward to southward, from minus 45 to 25 degrees Fahrenheit (minus 42.11 to minus 6.66 degrees Celsius).

Wooded wetlands with bogs, breeding ponds, cool-watered, slow-moving lakes, rivers, streams and swamps, dense, low-lying vegetation, flooded ditches and meadows and rocky ravines promote pickerel frogs.

Lang Elliott, Carl Gerhardt and Carlos Davidson quantify 1.75- to 3.4375-inch (4.44- to 8.73-centimeter) snout-vent (excrementary opening) lengths in The Frogs and Toads of North America. Adults reveal on their tan bodies gold-rimmed, night-active eyes; light, unbroken dorsolateral (back-to-side) folds; two parallel rows of brown rectangular or squarish spots; orange-yellow inner thighs. Advertisement calls sound like grating, soft, two-second snores, similar to drawn-out, northern leopard frog-like, rattling, snore-like, three-second advertisements; and like garbled, green frog-like, throaty guck vocalizations.

North American pickerel frog habitats team guck-punctuated snoring with toxin-secreting bodies with dorsolateral folds, black-brown, rectangular, squarish spots in two parallel rows and orange-yellow inner thighs.

pickerel frog (Lithobates palustris) under synonym Rana palustris; depiction by Italian-born scientific illustrator J. Sera, lithograph by George Lehman/Lehman & Duval Lithographers; J.E. Holbrook's North American Herpetology (1836), vol. I, Plate XIV, opposite page 93: Public Domain via Biodiversity Heritage Library

Acknowledgment

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

Image credits:

pickerel frog (Lithobates palustris; formerly Rana palustris); Leesylvania State Park, Woodbridge, Prince William County, Northern Virginia; Sept. 2, 2012: Judy Gallagher (judygva), CC BY 2.0, via Flickr @ https://www.flickr.com/photos/52450054@N04/7917501420/

pickerel frog (Lithobates palustris) under synonym Rana palustris; depiction by Italian-born scientific illustrator J. Sera, lithograph by George Lehman/Lehman & Duval Lithographers; J.E. Holbrook's North American Herpetology (1836), vol. I, Plate XIV, opposite page 93: Public Domain via Biodiversity Heritage Library @ https://biodiversitylibrary.org/page/4075426

For further information:

Elliott, Lang; Carl Gerhardt; and Carlos Davidson. 2009. The Frogs and Toads of North America: A Comprehensive Guide to Their Identification, Behavior and Calls. Boston MA; New York NY: Houghton Mifflin Harcourt.

Frost, Darrel. "Lithobates palustris (LeConte, 1825)." American Museum of Natural History > Our Research > Vertebrate Zoology > Herpetology > Amphibians Species of the World Database.
Available @ http://research.amnh.org/vz/herpetology/amphibia/index.php//Amphibia/Anura/Ranidae/Lithobates/Lithobates-palustris

Holbrook, John Edwards, M.D. 1836. "Rana palustris." North American Herpetology; Or, A Description of the Reptiles Inhabiting the United States. Vol. I: 93-94. Philadelphia PA: J. Dobson.
Available via Biodiversity Heritage Library @ https://biodiversitylibrary.org/page/4075426

Le Conte, Captain John. 1825. "Remarks on the American species of the Genera Hyla and Rana: 2. Rana palustris, or marsh frog." Annals of the Lyceum of Natural History of New-York, vol. I, part 1: 282. New York NY: J. Seymour.
Available @ https://archive.org/stream/annalsoflyceumof11824lyce#page/282/mode/1up

Patterson, Daniel, ed. 2008. Early American Nature Writers. Westport CT: Greenwood Press.

"The 2012 USDA Plant Hardiness Zone Map." The National Gardening Association > Gardening Tools > Learning Library USDA Hardiness Zone > USDA Plant Hardiness Zone Map.
Available @ https://garden.org/nga/zipzone/2012/