Spotted Frog {Rana pretiosa) 



Description: The adult has a snout-vent length of 2-4". Adults are dark to light brown, gray, or 

 olive green with dark spots (frequently with lighter centers) found on the back, sides and legs. 

 The number and pattern of spotting is quite variable. The back and sides are often covered 

 with small bumps. The underside of the legs is bright red, salmon, or orange; this bright 

 color may extend up to the chin or be replaced by a light, mottled gray on the chin, chest, 

 and/or belly. In younger subadults, bright leg color is often lacking and instead a light, 

 lemon-colored wash is present. In these subadults there is often a dark mask present, with a 

 light jaw stripe extending to the shoulder; both the mask and jaw stripe may be less obvious 

 in larger, older animals. 



Eggs and Tadpoles: Eggs are laid in large, globular masses of 150-500 at the surface of the 

 water. The tadpoles are dark green to brown on top with some gold flecking whereas the 

 underside has an iridescent bronze or silver color. Total length of tadpoles may reach 3"; the 

 eyes are located on top of the head. 



Similar species: The bright-colored pigment on the undersides of the adult's legs distinguish this 

 species from all other frogs in Montana. Younger individuals, without colored legs, may 

 usually be distinguished from other frogs by a combination of: 1 ) dorsal spots usually present 

 but not surrounded by light-colored halos; 2) dorsolateral folds present; 3) toes without pads 

 at the tips; and 4) a pale gray, (rather than white) belly. 



Habitat and Habits: Spotted Frogs are regularly found at the water's edge in openings within 

 forest habitats. Wetlands in or near treeline are also used, but populations are uncommon in 

 the large, open intermountain valleys. The Spotted Frog was found at only two ponds on the 

 study area, despite the ease of surveying for this species. It is apparently uncommon on the 

 study area, probably due to the scarcity of permanent ponds in a forest landscape and the 

 ephemeral nature of many of the streams. Across western Montana, breeding takes place in 

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

 ponds in streams. All the egg masses in a particular pond are often found in the same 

 location at the margin of the pond; therefore, the eggs are susceptible to drying up if pond 

 levels recede substantially before hatching. The only tadpoles observed were found 31 May 

 96 at a pond near the North Fork of Dupuyer Creek. Previous surveys on the L&CNF 

 indicated that tadpoles in this area metamorphosed beginning in late July. Throughout their 

 range. Spotted Frog eggs hatch in 2-3 weeks and tadpoles take 2-14 months to 

 metamorphose, depending on water temperature (Nussbaum at al. 1983, Turner 1958). 

 Young and adult frogs often disperse into marsh and forest habitats but are not usually found 

 far from open water. 



Status: The most common ft-og in western Montana, there are no indications of declines in the 

 state. It was observed on the study area, however only a single breeding location is known at 

 this time and, if new ones are found they should be reported. It was not seen outside of 

 forested habitat. Significant declines are known fi'om the southern end of the range (Nevada, 

 southern Idaho, Utah). While significant declines are also apparent in coastal Washington 

 (McAllister at al. 1993), Oregon, and California, recent research indicates that those 

 populations are actually a different species (Green at al. 1996, 1997); if that taxonomic 

 arrangement is accepted, the fi'og here in Montana will become the Columbian Spotted Frog 

 {Rana luteivenths). 



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