AmphibiaWeb - Rana sylvatica
AMPHIBIAWEB
Rana sylvatica
Wood Frog
family: Ranidae
Taxonomic Notes: This species was placed in the genus Lithobates by Frost et al. (2006). However, Yuan et al. (2016, Systematic Biology, doi: 10.1093/sysbio/syw055) showed that this action created problems of paraphyly in other genera. Yuan et al. (2016) recognized subgenera within Rana for the major traditional species groups, with Lithobates used as the subgenus for the Rana palmipes group. AmphibiaWeb recommends the optional use of these subgenera to refer to these major species groups, with names written as Rana (Aquarana) catesbeiana, for example. However, Rana sylvatica has proven difficult to resolve phylogenetically and it remains the only member of the genus not assigned to a subgenus.

© 2007 Twan Leenders (1 of 90)
Conservation Status (definitions)
IUCN (Red List) Status Least Concern (LC)
NatureServe Status Use NatureServe Explorer to see status.
CITES No CITES Listing
National Status None
Regional Status None
Access Conservation Needs Assessment Report.

   

 

View distribution map in BerkeleyMapper.

Description
Adults are 37 to 83 mm in length, and females are larger. Prominent dorsolateral folds extend from the bead to near the vent. The lateral edge of each fold is darker than the medial edge. The smooth to moderately rough back often has short folds between the dorsolateral folds. Toes are webbed, with tow or three phalanges of the fourth toe free of the web. Dorsal coloring may be gray to tan to vivid reddish brown , and is coppery or golden in some individuals. Females are usually more reddish. Black or dark brown markings may be present on the back and sides, and many northern and western specimens have a middorsal white line. A conspicuous dark brown or blackish mask extends from the snout to just behind the tympanum. The white venter is sometimes darkly mottled on the throat and breast, and is smooth except for a granular region under the thighs. There also is a prominint dark marking in the pectoral region. The tympanum is smaller than the eye. Males have paired vocal sacs, stout forelegs, and a "thumb" and enlarged webbing between the toes during the breeding season.

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Canada, United States

U.S. state distribution from AmphibiaWeb's database: Alaska, Alabama, Arkansas, Colorado, Connecticut, District of Columbia, Delaware, Georgia, Idaho, Illinois, Indiana, Kentucky, Massachusetts, Maryland, Maine, Michigan, Minnesota, Missouri, Montana, North Carolina, North Dakota, New Hampshire, New Jersey, New York, Ohio, Oklahoma, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Virginia, Vermont, Wisconsin, West Virginia, Wyoming

Canadian province distribution from AmphibiaWeb's database: Alberta, British Columbia, Manitoba, New Brunswick, Newfoundland and Labrador, Nova Scotia, Northwest Territories, Nunavut, Ontario, Prince Edward Island, Quebec, Saskatchewan, Yukon

 

View distribution map in BerkeleyMapper.
R. sylvatica is the only cold-blooded tetrapod known to occur north of the Artic Circle in the Western Hemisphere. It is found over most of Alaska and Canada and over the northeastern part of the United States. Its northern limit lies along the treeline from Alaska to Labrador. Its range extends southward coastally to Maryland and in the Appalachian Mountains to northern Georgia and northeastern Tennessee. The southern edge of the range passes northward through southern Illinois and the norteastern corner of South Dakota, the noreastern half of North Dakota, northern Idoah and westward in Canada to near the Pacific coast. Isolated populations are found in souteastern Wyoming and northern Colorado, in eastern Kansas, in the Ozark Mountains of Arkansas and Missouri, and perhaps in areas north of the Artic tree line.
It is a terrestrial species, often found in or near moist wooded areas, sometimes considerable distances from open water.

Life History, Abundance, Activity, and Special Behaviors
Rana sylvatica is well known for hibernating and freezing during winters. Nitrogen balancing has been known to play a role in osmoregulation, cryoprotection, and metabolic inhibition in amphibians. In some vertebrates, gut bacteria aid this balance by producing urease, an enzyme that breaks down urea. However, until 2018 it was unknown if gut bacteria played a role in amphibian nitrogen-recycling. Wiebler et al. (2018) investigated the role of hindgut microbiomes in Rana sylvatica, which is known for storing urea during its hibernation, by comparing the urease activity and microbial community in hibernating males with active males and by artificially increasing the concentration of urea in the blood stream. They found that while active frogs have a greater concentration of bacteria in their hindgut, hibernating frogs have a greater diversity of bacteria that produce urease, and have more urease activity. Additionally, increasing the concentration of urea in the blood stream increase bacterial urease activity. They, thus, provided the first report of nitrogen-recycling by hindgut bacteria in amphibians.

Comments

This species was featured as News of the Week on 14 January 2019:

Human activities ranging from vehicle traffic to industry are making the world an increasingly noisy place to live in; two recent studies show frogs have found ways to cope with the human soundscape. Tennessen et al. (2018) studied wood frogs (Rana sylvatica) in northeastern United States where noise from vehicle traffic is physiologically stressful to recently metamorphosed tadpoles, negatively impacting frog health. However, these researchers found that wood frogs from populations living near human noise have rapidly evolved to no longer be stressed by noisy human environments. In Panama, predators like bats and midges avoid noisy urban areas because they rely on sounds to hunt. Halfwerk and colleagues (2018) found that male tĂșngara frogs (Engystomops pustulosus) from urban habitats can flexibly adjust their calls. Urban dwelling male tĂșngara create more conspicuous calls, which are more attractive to females. When these urban males are placed in the forest, they adjust their calls to be less conspicuous and therefore less obvious to predators. Male tĂșngara frogs from forests are unable to flexibly adjust their calls if they are placed in the city. Together, these studies show that some frogs species can rapidly evolve to deal with noisy human environments whereas others can adjust their behaviors accordingly (Written by Max Lambert).

References

Martof, B. S. (1963). ''Rana sylvatica (Le Conte). Wood Frog.'' Catalogue of American Amphibians and Reptiles. American Society of Ichthyologists and Herpetologists, 86.1-86.4.

Wiebler JM, Kohl KD, Lee Jr RE, Costanzo JP. (2018). ''Urea hydrolysis by gut bacteria in a hibernating frog: evidence for urea-nitrogen recycling in Amphibia.'' Proceedings of the Royal Society B, 285, 20180241.



Originally submitted by: Franziska Sandmeier (first posted 2001-02-21)

Edited by: Arie van der Meijden (28/2/2001) Ann T. Chang (2019-01-16)

Species Account Citation: AmphibiaWeb 2019 Rana sylvatica: Wood Frog <https://amphibiaweb.org/species/5162> University of California, Berkeley, CA, USA. Accessed Aug 3, 2021.



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Citation: AmphibiaWeb. 2021. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 3 Aug 2021.

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