What do they look like?

Southern bog lemmings are small voles, weighing 20 to 50 grams and measuring 110 to 140 mm in total length. The fur on the back ranges in color from a reddish to dark brown that has a grizzled appearance. The belly is silver-gray. Females of this species have 6 mammary glands, which distinguishes it from its closest relative, the northern bog lemming, which has 8 mammary glands. The tail is short, barely longer than the hind foot.

Where in the world do they live?

Southern bog lemmings are found in eastern North America, from southeast Canada to western Minnesota, down to southwest Kansas and east to northeast North Carolina.

What kind of habitat do they need?

Southern bog lemmings occur mainly in sphagnum bogs, as their name suggests, but they may also occur in grasslands, and in Canada they occur in coniferous or deciduous forests. In Michigan, they can be found in clear cuts, old fields, or upland woods. They tend to live in habitats within their geographic range where they do not have to compete with meadow voles.

How do they reproduce?

Breeding occurs in all seasons, especially where there is plentiful food. Most young are born between April and September. Females may have many litters in a year--one captive bore 6 litters in 22 weeks. Wild females produce 2 or 3 litters per year. Pregnancy lasts from 23 to 26 days. Average litter size is 3 but can range from 1 to 8. Males can reach sexual maturity in 5 weeks.

Southern bog lemmings weigh 3.7 grams at birth. Young are born with no fur, closed eyes, and with the ear flaps folded over. Claws are visible at birth. By the end of the first week, the young are well furred. The female nurses her young for three weeks.

How long do they live?

Wild southern bog lemmings usually do not live for more than a year. In captivity, they may live up to 29 months.

How do they behave?

Not much is known about social interactions of southern bog lemmings. Anywhere from 6 to 35 individual bog lemmings may be found per hectare of land. Southern bog lemmings do not hibernate and can be active any time of day or night, but they are mostly nocturnal. They makes runways and tunnels or use those of other species. They also builds nests from dry grasses which are concealed under stumps or mounds of moss.

How do they communicate with each other?

Southern bog lemmings are thought to communicate using scent marking. They also make squeaking vocalizations.

What do they eat?

Southern bog lemmings eat mostly vegetation such as grasses, sedges, mosses, fruits, fungi, bark and roots. Bog lemmings snip stems near the ground to get access to the upper parts. Often surrounding vegetation stops the stems from falling, so additional snips must be made. Some invertebrates such as slugs and snails are also taken. The jaws are powerful and thought to be used quite often for gnawing.

What eats them and how do they avoid being eaten?

Southern bog lemmings have many predators, including owls, red foxes, gray foxes, domestic dogs, badgers, and house cats.

What roles do they have in the ecosystem?

Southern bog lemmings have important ecosystem roles as food for a number of predators (see above) and as competitors with other small rodents, such as meadow voles.

Are they endangered?

Once very common, numbers seem to be declining as a result of habitat destruction and the overgrowth of bogs. One subspecies, the Dismal Swamp bog lemming, is thought endangered and possibly extinct. Other subspecies also appear to be threatened.

Contributors

Bridget Fahey (author), University of Michigan: June, 1999.

Allison Poor (editor), University of Michigan: March, 2005.

References

Linzey, A. V. 1983. Syamptomys cooperi. Mammalian Species, no. 210: 1-5.

Kurta, A. 1995. Mammals of the Great Lakes Region. University of Michigan Press, Ann Arbor MI

Nowak, R.M. Walker's Mammals of the World, 5th Edition. Johns Hopkins University Press.

"Animal Life Histories Database" (On-line).

Ruff, S., D. Wilson. 1999. The Smithsonian Book of North American Mammals. Washington [D.C.]: Smithsonian Institution Press in association with the American Society of Mammalogists.