Species known to be present on the Sioux District of the Custer National Forest 



Tiger Salamander (Ambystoma tigrimim) 



Description: Adults have a smooth moist skin without scales and the color pattern is highly 

 variable; usually the background color is dark, with lighter blotches of yellow, tan or green. 

 The adult is large and heavy-bodied with a snout-vent length of 3-6". Adult Tiger 

 Salamanders can be separated from other Montana species by: 1) their large sized and heavy 

 body; and 2) two prominent tubercles on the bottom of each hind foot. 

 Eggs and Larvae: Egg masses are typically laid in small clusters of 5-120, but may be laid 

 singly (Nussbaum et al. 1983, Leonard et al. 1993). They are usually attached to vegetation 

 and placed 2"- 10" below the surface of the water (Hammerson 1982a). Larval Tiger 

 Salamanders are typically pale green or brown-colored, though those living in bentonite clay 

 ponds may be nearly white. They are found in lakes and ponds, have external gills, and are 

 relatively large (0.75-4" snout- vent) and heavy-bodied. 



Similar species: None in the Sioux-CNF. Adult Tiger Salamanders have two prominent 



tubercles on the bottom of each hind foot which Idaho Giant Salamanders lack. Idaho Giant 

 Salamanders also have a more marbled color pattern and a very large head. 



Habitat and Habits: Tiger Salamanders in Montana and South Dakota are primarily associated 

 with prairie or agricultural habitats in eastern Montana. On the Sioux-CNF the are also foimd 

 in wooded draws and ponderosa pine forests. They breed in ponds or lakes, usually those 

 without fish present. In arid areas, they may also be found in springs, intermittent streams, 

 and stock ponds. Larvae found in our June surveys were mid- to large-sized. They were not 

 found at any locations in September surveys; they had apparently already transformed. In 

 Blue Lake, Madison County, Montana, eggs were laid from early June to mid-August, 

 hatched in about 2 weeks, and metamorphosis occurred after more than a year (Micken 1968, 

 1971). In Colorado and Wyoming egg laying takes place from mid-March to mid- August 

 (Hammerson 1982a, Baxter and Stone 1985). Following breeding, adults may either remain 

 in the pond or move to upland areas and live in burrows of their own or in those of other 

 animals. Eggs hatch in 2-5 weeks in Colorado and metamorphosis occurs after 2-24 months 

 (Hammerson 1982a). In some locations, such as Blue Lake in Madison County, larval 

 salamanders never transform, but rather become sexually mature and breed while still 

 retaining external gills. This process is referred to as neoteny and these salamanders are 

 often referred to as "axolotls" or "water dogs." Neoteny may be rare on the Sioux-CNF since 

 none were found in September-October surveys. 



Surveying: Larvae and eggs may seen in ponds during the day and may be sampled with a 

 dipnet. Migrations of hundreds or thousands of newly transformed adults are occasionally 

 seen in mid-late summer or early fall. During the breeding season, adults are often seen 

 moving to or away from the water or breeding in it. Pitfall and minnow traps may be used at 

 this time to capture adults. Throughout the rest of the summer adults, are difficult to find; 

 using pitfall traps or driving roads on warm rainy nights may be the best techniques then. 



Status: The most common salamander in eastern Montana. They are known from all Units in 

 the Sioux-CNF except the Short Pine Hills and should be considered common on the District. 



Montana Natural Heritage Program rank: G5 S5. 



