Tailed Frog (Ascaphus truei) 



Description: Adults are gray or brown with gray, brown, or occasionally yellow blotches; the 

 skin has a distinctly bumpy texture. The adult has a snout-vent length of 1 .5-2" and lacks a 

 tympanum. The outer toe of the hind foot is broader than the other toes. The male has a 

 bulbous "tail" which acts as a penis. 



Eggs and Larvae: Approximately 50 eggs are laid in rosary-like strings attached to the 

 underside of rocks. The tadpole (up to 2" long) is unique in that it has a large mouth 

 modified into a sucker; the color is quite variable. 



Similar species: No other frog or toad has the outer toe of the hind foot broader than the other 

 toes; all other frogs and toads have a tympanum behind each eye. 



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

 the L&CNF. they have been found only on the RMRD in four locations, and none on the 

 study area. The elevations range from 4900 feet in Falls Creek to about 6000 feet in a small 

 stream on the Mount Wright trail. This elevation range will likely increase with additional 

 sightings from the area. In the Cascade Mountains of Washington and Oregon, the Tailed 

 Frog appears to be ver>- sensitive to siltation and frequently disappears in and downstream 

 from clearcuts and water diversions (Bury. pers. comm.). Preliminarv' findings do not 

 indicate that this is the case in Montana. Eggs are laid during the late summer and take 

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

 water temperature (Nussbaum at al. 1983; Metter 1967). Sexual maturit>- in Montana is 

 attained at 6-7 years old, (Daugherty and Sheldon 1 982) which is the latest age for sexual 

 maturity of any North American amphibian. 



Status: Tailed Frogs were not found in any streams on the study area, however, they are known 

 from a small tributar\' to the West Fork Teton River a few miles west of the study area. They 

 are known from only a few locations east of the Continental Divide on the L&CNF and 

 Beaverhead National Forest. Many of the streams on the study area periodically dry up, 

 which would not allow Tailed Frogs, with their multi-year tadpole stage, to survive. They 

 may still be found to occur in the upper reaches of some streams on the study area, if any 

 flow year-long during drought years. While Tailed Frogs should be considered a species with 

 a ver>' localized distribution on the RMRD of the L&CNF. it may be more common and 

 widespread in suitable habitat than is currently knovm. It is common and widespread in 

 western Montana. Due to declines in the Cascade Mountains apparently related to logging, 

 the Tailed Frog is currently on the Watch List of the Montana Natural Heritage Program. 



Montana Natural Heritage Program rank: G5 S3S4. Watch List. 



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