MOLES, SHREW MOLES, AND DESMANS: Talpidae

PHYSICAL CHARACTERISTICS

Moles are small, short-legged, smooth-furred animals with tiny, sometimes hidden eyes, and long, nearly naked snouts. Many land-living moles have large, wide, shovel-like front feet adapted for digging through the soil. Some moles, including the desmans, are swimmers and have slender, webbed forefeet. Shrew moles, which live on land but dig little, if at all, have feet that are neither shovel-like nor webbed. Overall, adult moles range from about 2.4 to 17.0 inches (6 to 43 centimeters) in body length and another 0.6 to 8.3 inches (1.5 to 21.5 centimeters) in tail length. They weigh from 0.4 ounces (12 grams) in the smallest species to 7.8 ounces (220 grams) in the largest.

GEOGRAPHIC RANGE

Moles, shrew moles, and desmans are found in the United States, Canada, Mexico, and much of Europe and Asia.

HABITAT

About three-quarters of the species in this family live much of their lives underground. A few live above ground on land, and others spend a good deal of their time in or near the water. Those that prefer the water usually make their homes near fresh water, but a few will also enter brackish water, water that is somewhat salty.

DIET

The primary diet among the moles is insects, earthworms, centipedes, and other invertebrates, animals without backbones, but many will also eat roots and other parts of plants. Water-living species may also include frogs and fish in their diet.

BEHAVIOR AND REPRODUCTION

Most moles have long and narrow snouts that they are able to wiggle and bend. The snout tip has tiny Elmer's organs that the mole uses to sense its environment and to find prey. Desmans that spend a good amount of time underwater use their snouts for several purposes. In one common behavior, a desman will stick just its snout tip out of the water to sniff the air for prey as well as predators, animals that hunt them for food. They will also dig through the water bottom with their snouts looking for food.

Some moles are active mainly at night, but others move around both day and night. The land-living, digging species are capable of making tunnels quickly for such a small animal. The eastern mole, which is less than 12 inches (30 centimeters) long from the tip of its nose to the end of its tail, can tunnel up to 15 feet (4.6 meters) in a single hour, and more than 100 feet (30 meters) in a day. Their tunnels are often visible from above ground, and look like long, sometimes-branching strings of broken ground. These are called mole runs. A molehill is a circular mound of dirt that is created when the mole pops above ground from the tunnel. Both the land-living and the water-loving species also dig deeper chambers for breeding and to escape the winter cold. Moles usually spend their lives alone, although some are more social. Reports suggest that Russian desmans may share their dens on occasion.

After mating one or two months earlier, most moles have one set, or litter, of about three to five babies in early to midsummer. A few species have one or more additional litters later in the year. The young are helpless and naked at birth, but after approximately four to six weeks, they are ready to leave the mother. The young can have babies of their own within a year.

IS IT A SHREW OR A MOLE?

At first glance, an observer might think that the smallest mole in North America is actually a shrew. Its size of just 3.5 to 5.2 inches (8.9 to 13.2 centimeters) is similar to shrews, and it does not have the large front feet that are common in many moles. Most of its activity occurs above ground, where it runs beneath the leaf litter in a manner similar to shrews. Land-living moles, on the other hand, are mainly tunneling animals. Even its name can be confusing. This small animal is called the American shrew-mole.

MOLES, SHREW MOLES, DESMANS, AND PEOPLE

The land-living, tunneling moles have the greatest contact with humans. Their tunneling activity is beneficial in that it loosens the soil and actually helps plants to grow, but their plant-eating habits and the visible mole runs frequently make them an unwelcome guest in yards, gardens, and farm fields. At one time, people also hunted moles for their silky fur, which was used for collars and cuffs on women's clothing. People even hunted some species, like the Russian desman, for their scent, which was used in perfumes.

CONSERVATION STATUS

According to the World Conservation Union (IUCN), two species are Critically Endangered, facing an extremely high risk of extinction in the wild. Five species are Endangered, facing a very high risk of extinction in the wild, and three are Vulnerable, facing a high risk of extinction in the wild. That means that nearly one quarter of all mole species are at some risk. The U.S. Fish and Wildlife Service lists no species as endangered. Many of the at-risk moles have small populations and/or live in habitats that are disappearing due to human activity. In addition, some species are facing threats from hunting or from introduced species that are invading their habitat. The Vulnerable Russian desman, for example, is now competing for food and shelter with the introduced muskrat and coypu (KOY-poo).

EASTERN MOLE (Scalopus aquaticus): SPECIES ACCOUNTS

Physical characteristics: Eastern moles are shiny grayish, occasionally black, moles with very large, clawed, shovel-like front feet that are well-suited for digging. A typical adult, which has a short tail, may be 5.9 to 7.9 inches (15 to 20 centimeters) long and weigh 3.2 to 5.0 ounces (90 to 143 grams).

Geographic range: Eastern moles are found in the eastern United States, far southern Canada, and far northern Mexico.

Habitat: Eastern moles live much of their lives underground in good soils in forests or grasslands.

Diet: Eastern moles eat mostly grubs and earthworms, but also centipedes and slugs. If they come across a root or seed during their tunneling, they will also eat those.

Behavior and reproduction: Eastern moles spend much of their time alone, making shallow tunnels in search of food. They also make deeper, living chambers. Their below-ground life protects them from most predators, although dogs, cats and other large digging mammals will sometimes root out a mole. Rarely, when a mole pops out of its tunnel, a nearby owl or snake will attack it. Moles mate once a year in early spring—a bit earlier in warmer areas and later in cooler climates—and build a nest in an underground chamber. About a month and a half afterward, the mother gives birth to a litter of three to five young. They stay with her for four to five weeks, and are ready to become parents themselves by the following spring.

Eastern moles and people: Most people are familiar with eastern moles from their mole runs, which are visible above the ground and often considered unsightly. Moles will also eat some crop roots, so they are sometimes considered pests. Homeowners, gardeners, and farmers frequently try various methods to rid their yards and fields of the moles.

Conservation status: Eastern moles are not threatened. ∎

STAR-NOSED MOLE (Condylura cristata): SPECIES ACCOUNTS

Physical characteristics: This dark-brown mole is best-known for the collection of twenty-two short and pink, fleshy tentacles on the tip of its snout. They have wide, clawed hands, and a tail that is almost as long as their body. Adults range from 6.1 to 8.1 inches (15.5 to 20.5 centimeters) and weigh 1.1 to 3.0 ounces (30 to 85 grams).

Geographic range: Star-nosed moles are found in the eastern United States and eastern Canada.

Habitat: Star-nosed moles prefer wet meadows and forests near water. Occasionally waterside homeowners may find evidence of one in a moist lawn area.

Diet: Star-nosed moles like grubs, earthworms, and other invertebrates, and will occasionally eat a small fish.

Behavior and reproduction: A star-nosed mole's always-wiggling tentacles act like feelers and help the animal to find its food and to make its way through the dark tunnels it digs. Active all year, and both day and night, this mole not only hunts for food inside its tunnels but above ground and in the water. Predators vary depending on the mole's location. When they are in the water, fish pose a threat. On land, meat-eating birds, snakes, and mammals may attack and kill moles. Other moles make long and winding mole runs, but the usual outward sign of the star-nosed mole is its molehills, which are small mounds of dirt at the entrances and exits for their tunnels. Although they are usually loners, two or more individuals may spend the winter together in shared, below-ground chambers. They do not hibernate, and even in the cold of winter, may leave their tunnels to dig through the snow. Females have one litter of two to seven babies each year. The young leave the nest in about a month, and begin having their own families by the following year.

Star-nosed moles and people: People rarely see star-nosed moles or recognize evidence of them, so interactions between these moles and humans are rare.

Conservation status: Star-nosed moles are not threatened. ∎

FOR MORE INFORMATION

Books:

Gorman, M. L., and R. D. Stone. The Natural History of Moles. Ithaca, NY: Comstock Publishing Associates, 1990.

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

Nevo, Eviatar, and Osvaldo Reig. Evolution of Subterranean Mammals at the Organismal and Molecular Levels. New York: Wiley-Liss, 1990.

Nowak, Ronald M. Walker's Mammals of the World. Baltimore: Johns Hopkins University Press, 1999.

Wilson, D., and S. Ruff, eds. The Smithsonian Book of North American Mammals. Washington, DC: Smithsonian Institution Press, 1999.

Periodicals:

Catania, K. C. "A Comparison of the Elmer's Organs of Three North American Moles: The Hairy-Tailed Mole (Parascalops breweri), the Star-Nosed Mole (Condylura cristata), and the Eastern Mole (Scalopus aquaticus)." Journal of Comparative Neurology 354 (1995): 150–160.

Mason, Matthew J., and Peter M. Narins. "Seismic Signal Use by Fossorial Mammals. " American Zoologist (November 2001): 1171–1184.

Web sites:

Hebert, P. D. N., ed. "Star-nosed mole, Condylura cristata." Canada's Aquatic Environments. http://www.aquatic.uoguelph.ca/mammals/freshwater/accounts/mole.htm (accessed on July 1, 2004).

Insectivore, Tree Shrew and Elephant Shrew Specialist Group. http://members.vienna.at/shrew/itsesAP95-desmana.html (accessed on July 1, 2004).

"Talpidae." Discover Life. http://www.discoverlife.org/nh/tx/Vertebrata/Mammalia/Talpidae/ (accessed on July 1, 2004).