Wood Frog (Rana sylvatica) 



Description: Adults have a prominent black facial mask that extends from the tip of the snout to 

 behind the tympanum; the mask is bordered below by a white lip-line. The upper 

 background color is quite variable, but most often brownish or gray. There may be dark 

 spots on the back, and a light-colored line may run down the middle of the back. The belly 

 is white to cream-colored, with often darker blotches on the chest and throat. Wood frogs 

 never have bright red, orange or yellow ventrally, as do adult (but often not subadult) Spotted 

 frogs. Wood frogs have relatively smooth skin, while similar sized Spotted frogs have skin 

 with small warts and bumps. 



Habitat and Habits: Wood frogs are regularly found near water in forest habitats. Breeding takes 

 place in lakes, ponds (temporary and permanent), springs, and occasionally backwaters or 

 beaver ponds in streams. Wood frogs are explosive breeders, with all the breeding activity 

 compressed into 1-2 weeks. They breed very early in the spring, often when ice is still being 

 formed on the ponds at night. Eggs are laid in globular masses which range from 50-1600 in 

 Alaska to 1000-3000 in Minnesota, and frequently all the masses in a particular pond are in 

 the same location (Breckenridge 1944, Nussbaum et al. 1983). Some researchers have found 

 Wood frogs to move into more terrestrial habitats following breeding (Heatwole 1961, Bellis 

 1962, Conant 1975), while others have found them near water for at least 6 weeks following 

 breeding (Haynes and Aird 1981). 



Surveying: During the spring months, both tadpoles and adults can be seen in and along the 

 water during the day and can be sampled with a dipnet. As the weather dries in the early 

 summer, the adults become much less visible but can still be found. In Wyoming, adults were 

 typically found in less than an hour of searching even during July surveys (Chris Garber, 

 pers. comm.). 



Status: Several unconfirmed museum records exist for Montana with the localities being 

 Bowman Lake (Glacier National Park, no date), Havre (no date), and Billings (1909); only 

 Bowman lake is a potentially correct habitat. Several additional unconfirmed sight records 

 exist but given the difficulty of distinguishing Wood frogs from young Spotted frogs, their 

 validity is questionable. Good quality close-up photos or specimens should be used to verify 

 the presence of this species in Montana. 



Montana Natural Heritage Program rank: G5 SR. 



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