Species Potentially Present on the Custer National Forest 



Snapping Turtle (Chelydra serpentina) 



Description: The Snapping Turtle appears too large for its shell. The upper shell is olive-gray, 

 or brovvTi to black with the posterior edge very serrated; it has three low keels with 

 protrusions positioned on each scute (a scale-like plate on the shell). The much-reduced 

 lower shell is cream-colored. A long, keeled tail and ^' .irty tubercles on the head and neck 

 are distinguishing characteristics. Males average about 10-20% larger than females, and have 

 the anal opening posterior to the rim of the upper shell (Ernst et al. 1994). Most adults range 

 from 13-30 pounds in Montana; the largest known Montana specimen was a 47-pound male 

 (Reichel and Flath 1995). 



£■^^5 and Young: The spherical, white, tough-shelled eggs are about 23-33 mm in diameter 

 (Ernst et al. 1994). They typically number 20-40 per clutch (Ernst et al. 1994). Coloration 

 of young turtles is similar to adults and the upper shell is 24-3 1 mm long. 



Similar Species: Spiny Softshells do not have scutes on the shell. Painted Turtles are smaller 

 and more colorful. 



Habits and Habitat: Snapping Turtles occur in stock ponds, reservoirs, sloughs, backwaters, 

 rivers, and irrigation ditches. They prefer waters with a soft mud or sand bottom, and much 

 aquatic vegetation or debris (Ernst et al. 1994). They do occasionally move overland, but are 

 found doing so less frequently then Painted Turtles. Food is mostly animal matter, consisting 

 of anything that can be caught, including small birds. While it is nocturnal in southern areas, 

 in the north it is most active in the morning and evening (Ernst et al. 1 994). Adult females 

 first breed at 12-19 years of age in Michigan and Ontario (Ernst et al. 1994). Eggs are laid in 

 nests excavated in sandy or gravelly areas or muskrat houses in late spring or early summer. 

 Sex is determined by the temperature of incubation (Ernst et al. 1994). Hibernation is in soft 

 bottoms, under cut-banks, or among submerged roots. Snapping Turtles have a reputation for 

 an evil temper, and are quick to bite. They can be handled safely if carried by the tail with 

 the upper shell away from the captor. 



Surveying: Although various turtle traps can be used for surveys, visual identification is suitable 

 for presence/absence studies since the three turtle species in Montana are easily 

 distinguished. Surveys should be done on surmy days with a pair of binoculars. During cold 

 or cloudy weather, turtles tend to remain underwater for long periods and can be missed on a 

 walk-through survey. 



Status and Distribution: Snapping Turtles occur in the Yellowstone River below Billings, the 

 Missouri River below Ft. Benton, and all tributaries with suitable water. They also occur in 

 water bodies that can be reached by a short trek across land. Irrigation ditches have 

 undoubtedly aided their distribution. Records from western Montana are probably the result 

 of translocation by humans. One historic location is near the Sioux-CNF on Boxelder Creek. 

 Visher (1914) says it is "fairly frequent in water holes." It should be watched for, particularly 

 at lower elevations in ponds and streams on the Sioux-CNF, and any animals located should 

 be documented. 



Montana Natural Heritage Program Rank: G5 S3. A Species of Special Concern. 



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