Southern bog lemmings have been collected and observed in grassy openings in woods, among mossy boulders in spruce forests, in bogs, in clearcuts, pastures, and power line rights-of-way. Only 8 have been recorded in the park since 1934. Bog lemmings are primarily nocturnal, and are active during all months of the year.

Species Measurements:
- Adult Total Length: 100-138 mm (4-5? in.)
- Tail: 15-27 mm (3/5-1 in.)
- Hind Foot: 18-21 mm (?-⅞ in.)
- Weight: 14-42 g (?-1 2/5 oz.)

Physical Characteristics:
The small, short-legged southern bog lemming is brownish-gray above and grayish below. The short tail is usually less than one inch long, and the massive head contains small ears that are nearly concealed in the fur. Each broad upper incisor has a shallow groove near its outer edge.

Habitat:
Southern bog lemmings have been taken in grassy openings in woods, among mossy boulders in spruce forests, in bogs, in clearcuts, pastures, and power line rights-of-way.

Reproduction:
In the park, southern bog lemmings generally breed from February to November. The Komareks recorded females containing one to four embryos in various stages of development during March: March 12 (4 - well developed), March 17 (1 - near birth), March 19 - (3 - half developed), and March 23 (1 - well developed). Embryos have also been recorded on July 5 and September 9. An immature Synaptomys was taken on October 31.
Gestation is 23 days, and several litters may be produced each year. Females usually mate again shortly after the birth of a litter. Litter sizes range from one to eight, although three or four is the usual size.

Newborn bog lemmings are pink except for the light gray dorsum. They weigh approximately 4 g. They are well furred by seven days. The lower incisors erupt between six and eight days, and the eyes open at 10 to 11 days of age. Weaning is completed by the end of the third week (Linzey, 1983).

Longevity:
Connor (1959) reported wild individuals surviving at least 7 to 8 months. A female captured as an adult lived two years and five months in captivity (Linzey, 1983). Most wild individuals probably survive less than one year.

Terrestrial Ecology:
Bog lemmings are primarily nocturnal and are active during all months of the year. Surface and underground runways are constructed. Nests may be built either above ground or in underground runways, and are composed of coarse fibers with a lining of finer material.

Home ranges, ranging from 0.04 ha to 0.32 ha, have been reported (Buckner, 1957; Connor, 1959; Getz, 1960). Population densities up to 51 per ha have been reported, although 4 to 12 per ha is probably more representative (Linzey, 1983).

Feeding Behavior:
Studies in Tennessee (Linzey and Linzey, 1973a) have shown that the food consists primarily of green vegetation but may be supplemented with fruits and fungi.

Predators and Defense:
Snakes, owls, hawks, and a variety of carnivorous mammals prey on bog lemmings.

Parasites:
Linzey recorded an undescribed louse and two mites (Androlaelaps glasgowi) (Linzey and Linzey, 1968). The undescribed species was described as Laelaps stupkai (Linzey and Crossley, 1971). Three specimens of Laelaps stupkai were removed from a male Synaptomys taken along Newfound Gap Road at Kanati Fork, 2,800 feet (Swain Co., North Carolina) in December (Linzey, 1995b).

The southern bog lemming ranges from New Brunswick and Nova Scotia, south along the Atlantic Coast to Virginia, and in the Appalachian Mountains to western North Carolina. It occurs westward to western Kansas, Nebraska, South Dakota, western Minnesota, and eastern Manitoba.

Southern bog lemmings are found most commonly at the higher elevations, although they have been recorded as low as 1,400 feet at Greenbrier (Linzey, 1995a). The Komareks recorded this species from "small, scattered grassy patches throughout the mountains," while Linzey has found bog lemmings in marshy meadows at Cataloochee and among rocks along a swiftly flowing mountain stream (Linzey, 1995b). The Komareks collected 26 individuals, but only 8 have been taken in the park since 1934.

References:

Buckner, C.H. 1957. Home Range of Synaptomys cooperi. Journal of Mammalogy 38(1): 132.

Connor, P.F. 1959. The Bog Lemming Synaptomys cooperi in Southern New Jersey. Publications of The Museum, Michigan State University, Biological Series 1: 161-248.

Getz, L.L. 1960. Home Ranges of the Bog Lemming. Journal of Mammalogy 41(3): 404-405.

Komarek, E. V. and R. Komarek. 1938. Mammals of the Great Smoky Mountains. Bulletin of the Chicago Academy of Sciences 5(6): 137-162.

Linzey, A.V. 1983. Synaptomys cooperi. Mammalian Species No. 210: 1-5. American Society of Mammalogists.

Linzey, A.V. 1999. Bog Lemming. Pages 657-658. In: D.E. Wilson, and S. Ruff (eds.). The Smithsonian Book of North American Mammals. Smithsonian Institution Press, Washington, D.C.

Linzey, D. W. 1995b. Mammals of Great Smoky Mountains National Park-1995 Update. Journal of the Elisha Mitchell Scientific Society 111(1): 1-81.

Linzey, D. W. and D.A. Crossley, Jr. 1971. A New Species of Laelaps from the Lemming Mouse, Synaptomys cooperi (Acarina: Laelaptidae). Proceedings of the Entomological Society of Washington 73(4): 408-410.

Linzey, D. W. and A.V. Linzey. 1973a. Notes on Food of Small Mammals from Great Smoky Mountains National Park, Tennessee-North Carolina. Journal of the Elisha Mitchell Scientific Society 89 (1 and 2): 6-14.

Linzey, D. W. and A.V. Linzey. 1973b. Notes on Parasites of small Mammals from Great Smoky Mountains National Park, Tennessee-North Carolina. Journal of the Elisha Mitchell Scientific Society 89 (1 and 2): 6-15.