In the spring, when the soil warms and insect activity increases, moles bear their young in nests. A female usually has two to four hairless babies. By early summer the young are out on their own, which accounts for the large amount of tunnelling at this time. Much mounding and tunnelling also occurs in the fall, when the moles migrate to other areas searching for more food. Since theirs is a dark, subterranean existence, moles have very little use for sight.
Some species have eyes that are tiny, undeveloped pin-pricks.
Others have eyes covered with skin. Most moles can distinguish light from dark, but they cannot define objects. To compensate for lack of sight, moles have incredible hearing and smelling abilities, and this is what enables them to find food. Sensory hairs cover the nose and front feet, which prevent them from bumping into the sides of their tunnels when doing 80 fpm. In fact, a mole's skin has more sensory organs than any other mammal.