Tailed Frog (Ascaphus truei) 



Description: Adults are gray or brown with gray, brown, or occasionally yellow blotches. The 

 adult has a snout- vent length of 3-5 cm. The outer toe of the hind foot is broader than the 

 other toes, unlike other frogs and toads. Tailed Frogs have no tympanum, while other frogs 

 and toads have a tympanum. The male has a bulbous "tail" which acts as an external 

 copulatory organ. Approximately 50 eggs are laid in rosary-like strings attached to the 

 underside of rocks. The tadpole (up to 5 cm snout- vent length) is unique in that it has a large 

 mouth modified into a sucker. 



Habitat and Habits: Tailed Frogs are found in and along small, swift, cold mountain streams, 

 often in a variety of forest cover (Harris 1984). In the BNF, they are found in all districts, 

 usually wdth trout and sculpin species in fast-moving, clear water with temperatures rarely 

 exceeding 54° F. The distribution of frogs within a stream was spotty and unpredictable on 

 the Kootenai National Forest (Werner and Reichel 1994). Adults show extreme philopatry 

 (Daugherty and Sheldon 1982b); absence in suitable habitat may be prolonged by low rates of 

 dispersal and colonization by adults. The highest elevations at which the Tailed Frog were 

 found on the Kootenai National Forest survey of 1994 was 5500' in the Whitefish Range. 

 The lower limit was 2800' along Libby Creek. Most records for the BNF are from lower 

 elevations (< 5000'), but Tailed Frogs have been collected as high as 6300' at Skalkaho Falls 

 in the Sapphire Mountains. Both the upper and lower elevation limits are probably dictated 

 more by the nature of the stream than elevation per se. In the Cascade Moimtains of 

 Washington and Oregon, the Tailed Frog appears to be very sensitive to siltation, and 

 frequently disappears in and downstream from clearcuts and water diversions (Com and Bury 

 1989, Bury, pers. comm.). Eggs are laid during the early summer and take approximately 4 

 weeks to hatch. Tadpoles take 1-4 years to metamorphose, depending on water temperature 

 (Nussbaum et al. 1983; Metter 1967). Sexual maturity in Montana is attained at ages 6-7 

 (Daugherty and Sheldon 1982a) which is the latest age for sexual maturity of any North 

 American amphibian. 



Surveying: Tadpoles are frequently found while fish shocking or conducting snorkel surveys. 

 They may also be found by turning over rocks in rapid water with a net held just downstream. 

 Adults are best found by walking up streams starting shortly after dark. 



Status: Apparently common in suitable habitat on the BNF and elsewhere in western Montana. 

 Tailed Frogs were present in 77 (48%) of 160 reaches on 84 streams surveyed on the BNF in 

 1995 (C. Clancy pers. comm.); >200 reports exist from the BNF since 1990 (Appendix 3). 

 Tailed Frogs have been reported from all four Forest Districts. The Tailed Frog was formerly 

 classified as a Candidate (C2) species by the USFWS, and is listed as an Animal Species of 

 Special Concern by the Montana Natural Heritage Program. 



Montana Natural Heritage Program rank: G3G4 S3S4 



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