Scalopus aquaticuseastern mole

Geographic Range

Scalopus aquaticus is found from southeastern Wyoming, South Dakota, and central Texas east to Michigan, Massachusetts, and New England, south to the tip of Florida, and north to Ontario. Small relict populations are found in southwestern Texas and in northwestern Mexico.

Habitat

The eastern mole prefers fields, meadows, pastures, and open woodland. It is not found in stony or gravelly soils or in clay but frequents moist, sandy, and loamy soils.

Physical Description

Head and body length in Scalopus aquaticus ranges from 110 to 170mm. Tail length ranges from 18 to 36mm. This size variation occurs on a gradient with the largest animals in the northeast and the smallest in the southwest. The robust body is covered with a thick velvety fur of a color that varies from silver to black to copper. The short tail is round, almost hairless, and indistinctly scaly. The feet are scantily haired above, naked below, and quite large. The webbing between the toes of each foot aids in digging. These moles have no external eyes or ears. It is thought that the poorly developed eye may be effective in detecting light.

  • Sexual Dimorphism
  • male larger
  • Range mass
    32.0 to 140.0 g
    1.13 to 4.93 oz
  • Average mass
    74.6 g
    2.63 oz
  • Range length
    110.0 to 170.0 mm
    4.33 to 6.69 in
  • Average basal metabolic rate
    0.378 W
    AnAge

Lifespan/Longevity

One captive animal lived longer than 36 months. In the wild it is likely that eastern moles live for less than this.

Behavior

A study in Kentucky found that S. aquaticus has daily activity peaks from 0800 to 1600 and from 2300 to 0400. Male home range averages 1.09 hectares whereas female home range averages only .28 hectares. These moles are not solitary. Their home ranges often overlap and several individuals have been found using the same tunnel systems. These tunnels are found in two forms. One type consists of deep, fairly permanent passageways that are used as burrows and as routes to feeding sites. The other consists of surface runways used for collecting food. Winter tunnels tend to be deeper than summer tunnels. Nest chambers of dry vegetation are usually below the surface underneath a boulder or the roots of a plant. Eastern moles can dig up to 4.5 meters in one hour with their powerful forefeet. One individual dug 31 meters of shallow tunnels in one day. Special morphological developments enable the mole to burrow with such speed. Their forefeet are large and as wide as they are long. The bones of their shoulder girdles and upper forelimbs provide broad suraces for muscle attachment. When they burrow, these moles essentially "dive" into the earth; they first thrust their forefeet into the soil and then follow with the head and body as they rotate their forelimbs and pull the loosened dirt backwards.

Scalopus aquaticus has high energy requirements and needs considerable amounts of food daily. As a result this animal forages widely; the incidence of inbreeding is low and the level of gene flow is fairly high. These patterns are unusual for fossorial mammals. Soil type and moisture are the eastern mole's major barriers to dispersal. They are good swimmers and are limited not by water itself but rather by the moist, clay-filled soils that accompany water courses. Soil acidity, which determines food abundance, provides another potential barrier to dispersal.

Communication and Perception

Although eastern moles have no vision, they may be able to detect the presence or absence of light. Their ears are also covered by a layer of skin but they may be able to detect sounds and vibrations. Eastern moles probably find their way around and detect prey by their acute senses of smell and touch.

Food Habits

Scalopus aquaticus eats primarily earthworms. It also eats insects and their larvae, some vegetation, and, in captivity, ground beef, dog food, mice, and small birds. Each day this mole eats 25 to 100% of its own weight in food.

  • Primary Diet
  • carnivore
    • eats non-insect arthropods

Predation

Eastern moles spend 99% of their time in their underground tunnels, there are few predators that can find and catch them there.

Ecosystem Roles

Eastern moles are important predators of insect larvae and other invertebrates, they can profoundly impact the communities of their prey. They also act to aerate and turn soil where they live through their extensive tunneling activities.

Economic Importance for Humans: Positive

As an insectivore, this animal eats the larvae of many insect pests. It also helps to aerate and turn over the soil.

  • Positive Impacts
  • controls pest population

Economic Importance for Humans: Negative

The eastern mole damages pastures and gardens by digging and injuring bulbs and root masses.

Conservation Status

The eastern mole is not endangered but has suffered persecution by avid gardeners and farmers who are displeased by the mounds of earth left behind and by the root damage caused by this animal.

Contributors

Antonia Gorog (author), University of Michigan-Ann Arbor.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

crepuscular

active at dawn and dusk

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

female parental care

parental care is carried out by females

fertilization

union of egg and spermatozoan

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

internal fertilization

fertilization takes place within the female's body

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

soil aeration

digs and breaks up soil so air and water can get in

solitary

lives alone

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

References

Harvey, M.J. (1976). Home Range, Movements and Diel Activity of the Eastern Mole, Scalopus aquaticus, The American Midland Naturalist, Vol. 95, No. 2.

Macdonald, David. (1984). The Encyclopedia of Mammals, Facts on File Publications, New York.

Nowak, Ronald M. and Paradiso, John L. (1983). Walker's Mammals of the World , The Johns Hopkins University Press, Baltimore and London.

Yates, Terry L. and Schmidly, David J. (1972). Mammalian Species, No. 105, The American Society of Mammalogists.

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