The gestation period of moles is approximately 42 days. A litter of 3 to 5 young are born each year, mainly in March and early April. Young pups leave their mother after only a few months and often travel aboveground because they are not as strong as adult moles. Moles are sexually mature about 10 months after birth and may live 3 to 5 years.
Nests of moles typically are located in the root system of trees. Deep runways lead from the den to hunting grounds. The den consists of irregular chambers connected to deep runways. The runways follow a course 5 to 8 inches beneath the surface of the ground. The chambers from which the runs radiate are about the size of a quart jar.
Moles are not social. Two or 3 moles may be trapped at the same spot, but that does not necessarily mean they had been living together in a burrow. Networks of runways that were independently made occasionally join separate burrows. They do not hibernate and are active during all seasons. Moles are most active when they are finding food during periods of rain in the late spring and early summer.
The home range of a male eastern mole is thought to be about 2.7 acres. Moles cover a larger amount of area than do most subterranean animals due to their substantial food requirements. Three to 5 moles per acre is considered an average to high density.
Moles live in underground burrows and come to the surface only rarely, often by accident. They favor wooded habitats where soil is loose and moist. Moles cannot survive in hard, compact, semi-arid soils. Moles make nesting burrows in high, dry areas, but they prefer to hunt in soil that is shaded, cool, moist, and populated by worms, grubs, and insects. This preference accounts for the often abundant populations of moles in lawns and parks. When the season gets very dry, moles often move to areas that are irrigated.
Most of the runway system consists of shallow tunnels ranging over its hunting ground. The subterranean hunting paths are 1¼ to 1½ inches in diameter. The tunnels may not be used again, or they may be used at irregular intervals. Eventually, the tunnels are filled by soil that is settling, especially after heavy rain. In some cases, moles push the soil they have excavated from their deep runways into shallow tunnels. Moles usually ridge up the surface of the soil, so their tunnels can be followed readily. In wet weather, runways are very shallow: during dry periods they range deeper, following the course of earthworms and insects. The maze of passages provides protective cover and traffic for several species of small mammals. Moles “swim” through soil, often near the surface of ground, in their search for food. In doing so, they may damage plants by disrupting the roots.
The teeth of moles are indicators of food preferences and general behavior. They are very sharp and resemble those of a coyote. Their diet consists mainly of insects, grubs, and worms. Plant material is taken inadvertently and when alternative foods are unavailable.
Moles consume 70% to 100% of their body weight each day. Experiments with captive moles show that they usually eat voraciously as long as they are supplied with a preferred food. The tremendous amount of energy expended in plowing through soil requires a correspondingly large amount of food.
Areas that have been used for feeding are identified by the volume of short, crooked, tunnels in a concentrated area (Figure 4). Mounds indicate where moles have pushed soil to the surface to clear deep tunnels.