Short usually black fur. Spade-like forelimbs. Pink fleshy snout. Head/body length: 113-159mm. Tail: 25-40mm. Weight: 72-128g. Males usually larger.
Moles are found throughout Britain but not in Ireland. An ice age wiped them out and Ireland was cut off by sea before they could re-colonise.
They are present in most habitats where the soil is deep enough to allow tunnelling but are uncommon in coniferous forests, on moorlands and in sand dunes, probably because their prey is scarce.
Moles spend almost all their lives underground in a system of permanent and semi-permanent tunnels. Surface tunnels are usually short-lived and occur in newly cultivated fields, in areas of light soil and in very shallow soils, where prey is concentrated just below the surface. More usual is a system of permanent deep burrows which form a complex network hundreds of metres long at varying depths in the soil. The deepest tunnels are used most in times of drought and low temperatures. Permanent tunnels are used repeatedly for feeding over long periods of time, sometimes by several generations of moles.
Within the tunnel system moles construct one or more spherical nest chambers, each lined with a ball of dry plant material. Nests are used for sleeping and for raising young.
Earthworms are the most important component of the mole’s diet; an 80g mole needs 50g of earthworms per day. Moles also eat many insect larvae particularly in the summer. Earthworms dominate the winter diet. Moles sometimes collect and store them alive in special chambers. The stored worms are immobilised by a bite to the head segment, 470 worms have been recorded in one chamber. Food is either actively dug out of the soil by the mole or more often collected from the floor of the tunnel. Many soil animals fall through into the tunnels. Moles rarely forage on the surface, most often in times of drought.
Males and females are solitary for most of the year, occupying exclusive territories. With the start of the breeding season males enlarge their territories, tunnelling over large areas in search of females. A litter of 3 or 4 naked babies is born in the spring. Fur starts to grow at 14 days, eyes open at 22 days and they are weaned at 4-5 weeks. The young start to leave the nest at 33 days and disperse from their mother’s range at 5-6 weeks. Dispersal takes place above ground and is a time of great danger. Moles are sexually mature in the spring following birth.
Most moles don’t live beyond 3 years but can live up to 6 years. Their main predators are owls, buzzards, stoats, cats and dogs but vehicles and humans also kill many.
Moles have no legal protection in the U.K. and are frequently regarded as pests by farmers, horticulturists and green-keepers. Surface tunnelling in newly planted fields may disturb plant roots so much that they will wilt and die. Mole hills cause damage to farm machinery. Mole hills also cause contamination of grass used to make silage.
At the beginning of the century moles were trapped in large numbers for their pelts but today they are killed as pests.
Moles can be beneficial to man, preying on many harmful insect larvae such as cockchafers and carrot fly, while tunnels help drain and aerate heavy soils.
How do moles dig?
Fore limbs are used to dig, shearing soil from the sides of the tunnel with alternate strokes. Hind limbs are used to brace the mole’s body against the tunnel walls. The mole turns round, scoops up accumulated soil with its fore limbs and pushes it along a previously dug side tunnel leading to the surface. The soil is pushed out above ground to form a molehill.
What is a mole fortress?
Moles sometimes construct very large mounds containing more than 750kg of soil. The mounds have an internal structure with one or more nests and a network of tunnels and can have food stores. They are built by males and females, and they occur most often in areas with shallow soil on hard substrate and in areas prone to flooding. The fortress acts as a refuge in times of flooding and also helps insulate the nest against low temperatures.