Scalopus aquaticus (Linnaeus)
Color photo by Barbara L. Clauson.
Description: Eastern moles are related to shrews, and of the four kinds of insectivores in Kansas, they are best adapted to underground life. Eastern moles are distinguished from other Kansas mammals by: 1) rudimentary eyes partially covered with skin, 2) no pinnae or external ears, 3) a short stubby tail that is used as a lever and is sensitive to touch, 4) a naked cone-shaped muzzle for probing soil for food, 5) front legs and feet that are highly adapted for burrowing in soil (they extend laterally from the stocky body like two paddles with the palms facing toward the rear), 6) palms that are about as wide as long, 7) each toe equipped with an unusually large claw, 8) relatively small hind feet, and 9) lax, short, silky silvery-gray to grayish brown hair which permits movement in any direction in the animal's tunnel. The skeletal structure of the forelimb is adapted for attachment of large muscles to provide powerful leverage for digging. Males are slightly larger than females.
Size: Adults may attain the following measurements: total length 136-187 mm; tail 19-38 mm; hind foot 19-27 mm; weight 54-99 grams.
Range and Habitat: Eastern moles live in burrows and are seldom seen above ground. It is found in favorable places throughout Kansas wherever soils are loose and earthworms and other invertebrates are plentiful. In western Kansas, it is found only in valleys where soils are deep and soft. The three subspecies in Kansas are Scalopus aquaticus caryi, Scalopus aquaticus aereus, and Scalopus aquaticus machrinoides.
Reproduction: Moles are solitary except during the breeding season in early spring. After a gestation period of approximately 40 days, two to five (usually four) naked, blind young are born in March or April. The nest is placed in well drained soils and constructed of grasses, leaves, and other plant fibers. It is frequently situated under objects that give overhead protection such as stumps or rocks. In 22 days the eyes open and in one month the young leave the nest, but remain with the mother for a short period. They are sexually mature at ten months.
Habits: Surface tunnels of eastern moles are characterized by continuous and irregular elevated ridges of soil which are forced up as the animal digs its way just beneath the ground in search of invertebrates. Soft soils are preferred, but hard soils can be penetrated, especially after rain softens the ground. A labyrinth of deeper tunnels is made that require removal of dirt to the surface, where it is pushed out perpendicularly as a conical mound. These deep subterranean tunnels contain the nest. Radiating from the nest are long tunnels that occupy the general hunting territory and from which lateral surface tunnels are temporarily extended. Abandoned subterranean and surface tunnels are used by other small mammals. Eastern moles do not hibernate in winter. During that time they are active and will dig tunnels into the snow, later filling them with soil. In spring, after snow melts, the solid cores some to rest upon the surface of the ground. This activity by eastern moles mixes and aerates the soil.
Food: The main food of eastern moles is larval insects and earthworms. Like shrews, they also eat snails, adult insects, and other invertebrates found while excavating tunnels. Although very little vegetation is directly consumed, secondary effects such as exposure of roots to air or disturbance from excavation of tunnels may cause death of some plants. The metabolic rate of eastern moles is not as rapid as that of the smaller shrews (1.8 cm3 oxygen per hour per gram body weight). Eastern moles may eat up to one-half times their weight daily, and, like shrews, are active foragers.
Remarks: Tracks of eastern moles are occasionally imprinted in dusty corridors of tunnels, or on the snow on those rare occasions when they come to the surface. Both male and female have a strong odor which may discourage predators. Maximum longevity is about three years.
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