wood frog

(Rana sylvatica)

               
Conservation Status

IUCN Red List

LC - Least Concern

wood frog

NatureServe

N5 - Secure

S5 - Secure

Minnesota

not listed

Occurrence

Common

Habitat

Moist wooded areas, ponds in woods and prairies.

Lifespan

3 to 4 years

Size

1¼ to 2

         
          Photo by Bill Reynolds

Identification

This is an easily recognized, medium-sized, terrestrial frog. It is 1½ to 3¼ long at maturity. Females are much larger than males.

The back (dorsal surface) is smooth to moderately rough. Prominent folds on each side of the back (dorsolateral) extend from the head to near the vent. The folds are light on top, dark on the sides. There are often additional short folds on the back between the dorsolateral folds.

The color varies. It is usually tan or brown, sometimes gray, reddish-brown, or yellowish-green. Females are usually more reddish than males. The back and sides may have dark mottling.

The belly (venter) is white, yellowish-white, or greenish-white and often has dark mottling on the throat and breast. There is a prominent dark mark on each side of the chest near the forelegs (pectoral region).

A prominent dark face mask extends from the snout to just behind the ear covering (tympanum). The tympanum is smaller than the eye. The upper lip is white.

The back legs have horizontal bands that may be dark or faint. The feet are webbed. On the fourth toe two or three joints are free of the webbing. Males have larger “thumbs” and stouter forelegs.

 
Voice

A short croak repeated several times. Often compared to the quacking of a duck.

 
Similar
Species

The prominent dark face mask, often referred to as a robber’s mask, on a brown frog is a unique identifying characteristic. No other species is similar in overall appearance.


Tadpole Food

Algae, decaying organic matter, eggs and embryos of some salamanders

 
Adult Food

Spiders, beetles, bugs, moth larvae, slugs, snails, and other insects and small invertebrates.

 
Life Cycle

Breeding is explosive. It occurs from late March to late April after the first warm spring rains, often before ice is completely off the pond. Males do not defend territories at this time but frantically swim after and grab other individuals hoping to find a receptive female.

After breeding, the female will deposit 300 to 1,000 eggs in a mass (clutch) loosely attached to emergent vegetation usually near the clutches of other females. Communal egg laying is thought to raise the temperature of the of the communal mass promoting faster development and to protect the inner eggs from leeches and other predators. Metamorphosis occurs at 65 to 130 days. The tadpole is 2¾ to 2 long preceding metamorphosis.

Adults overwinter under the shelter of a log, rock, bark, or leaf litter. They are freeze tolerant and can survive multiple freeze-thaw cycles. Glycerine is produced preventing the formation of ice crystals in vital organs.

Males typically live 3 years, females 4 years.

 
Behavior

Wood frogs are territorial. Territory size is usually about 100 square meters.

Summer months are spent in moist woods or wooded swamps, bogs or ravines. In late fall the frogs migrate to nearby upland areas to find a site to overwinter.


Distribution Distribution Map   Sources: 7, 11, 12, 13, 14, 24, 29, 73.

Comments

Taxonomy
In 2006 most North American true frogs were transferred from the genus Rana to the genus Lithobates by Frost et al. The change was controversial and was not accepted by all authorities. In 2008 and 2009 the change was rejected by Stuart, Pauly et al., and other systematic reviews, and in 2009 North American true frogs were returned to their previous classification. Lithobates is once again a subgenus of Rana. ITIS37 and Amphibian Species of the World61 continue to use the 2006-08 classification. NCBI34 and UniProt33 use the new classification. AmphibiaWeb60 suggests using the original name followed by the subgenus name in parentheses. In this case, Rana sylvatica, the species is not classified into a subgenus.


Taxonomy

Superorder:

Batrachia (amphibians)

 

Order:

Anura (frogs and toads)

 

Suborder:

Neobatrachia

 

Superfamily:

Ranoidea

 

Family:

Ranidae (true frogs)

 
Synonyms

Lithobates sylvaticus

Rana cantabrigensis

Rana cantabridgensis latiremis

Rana cantabrigensis evittata

Rana maslini

Rana sylvatica sylvatica

Rana sylvatica cantabrigensis

 
Common
Names

wood frog


 

 

 

 

 

 

 

Glossary

tympanum

The circular, disk-like membrane that covers the ear opening of some reptiles and amphibians.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

       

Visitor Photos

   
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Laurie Grimm


  wood frog    

Bill Reynolds


  wood frog    

       
       

MinnesotaSeasons.com Photos

   
  wood frog    
       
       

 

Camera

     

Slideshows

   
  Wood Frog
Andree Reno Sanborn
 
  Wood Frog  
 
About

Rana sylvatica

 
     
  Wood Frog (Lithobates sylvaticus)
Bill Keim
 
  Wood Frog (Lithobates sylvaticus)  
     
  Rana sylvatica (Wood Frog)
Allen Chartier
 
  Rana sylvatica (Wood Frog)  
     
  Wood Frog
Nick Scobel
 
  Wood Frog  
     
  Wood Frog (Rana sylvatica)
WisCBMnetwork
 
   
 
About

Published on Apr 30, 2012

No description available.

 
     

 

slideshow

     

Visitor Videos

   
Share your video of this amphibian.

     
     

Other Videos

 
  Time-lapse video of a wood frog (Rana sylvatica) thawing.
The Company of Biologists
 
   
 
About

Published on Jun 26, 2013

Time-lapse video of a wood frog (Rana sylvatica) thawing at 4°C following an experimental freezing exposure to --2°C for 24 h.

The original Commentary paper is available at http://jeb.biologists.org/content/216/11/1961.abstract

 
     
  Mating Wood Frogs, Rana sylvatica
mfb99
 
   
 
About

Uploaded on Apr 11, 2009
http://www.mister-toad.com

A collection of short video clips of calling and mating wood frogs (Rana sylvatica). Videos taken the first few days of April, 2009, on the University of Michigan's E.S. George Reserve.

 
     

 

Camcorder

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