Definitions

mole

mole

[mohl]
mole: see birthmark.
mole, in chemistry, a quantity of particles of any type equal to Avogadro's number, or 6.02×1023 particles. One gram-molecular weight of any molecular substance contains exactly one mole of molecules. The term mole is often used in place of gram-molecular weight; e.g., one speaks of 18 grams of water as one mole of water rather than as one gram-molecular weight of water. The mole is a unit in the International System of Units (SI).
mole, in zoology, common name for the small, burrowing, insectivorous mammals of the family Talpidae, found throughout the temperate Northern Hemisphere. Moles are trapped as pests, although they probably do less damage than the animals they destroy, and for their fur, which is highly valued. Typical moles have rounded bodies about 6 in. (15.2 cm) long covered with soft black or gray fur; they have pointed muzzles and lack external ears. They have acute hearing and a highly developed sense of touch at the ends of their noses and tails; their tiny eyes, covered with skin or buried in fur, are sensitive to changes in light level but provide little visual acuity. Moles have short, powerful legs and extremely broad front feet, which are used as shovels and are equipped with enormous digging claws. They can move backwards almost as rapidly as forwards, and most are good swimmers. Moles tunnel just below the surface of the ground, where they hunt for food. Their tunnels make ridges and mounds in fields, gardens, and lawns; quarters for living, nesting, and wintering are in deeper burrows. A single mole can dig about 20 yd (18 m) of tunnel in a day. Moles are voracious eaters, consuming about half their own weight daily. Their diet consists mainly of earthworms and insects, but also includes small mammals such as mice; one mole may even kill and eat another when they happen to meet. They are solitary most of the year, but during the breeding season they travel in pairs. The litter, born in the spring after four weeks of gestation, consists of two to seven young. Typical species include the common European mole, Talpia europaea, and the eastern, or garden, mole of North America, Scalopus aquaticus, both about 6 in. (15.2 cm) long with a 1-in. (2.54-cm) tail. The largest moles are the western moles of North America, genus Scapanus, which may reach a length of 9 in. (22.9 cm). The smallest New World mole is the 3-in. (7.6-cm) shrew mole, Neurotrichus gibsii, of the Pacific Northwest, which resembles a shrew and prefers a forest habitat, spending much time above ground. The strangest-looking of the family is the star-nosed mole, Condylure christata, of northeastern North America, which has a ring of mobile fleshy protuberances around its snout. This mole is a good diver and leads a semiaquatic life; apparently it uses the protuberances to pick up sounds in the water. There are no true moles in the Southern Hemisphere. The golden moles of S Africa are members of the insectivorous family Chrysochloridae; they are burrowing animals with bright golden fur. There are burrowing rodents in Africa called strand moles and burrowing marsupials in Australia called marsupial moles. True moles are classified in the phylum Chordata, subphylum Vertebrata, class Mammalia, order Insectivora, family Talpidae.

See study by K. Mellanby (1973).

Pigmented flat or fleshy skin mark, made up mostly of cells that produce melanin, which gives moles their light to dark brown or black colour and, in the dermis, a bluish cast. Thicker moles also contain nerve elements and connective tissue. Moles often begin in childhood, usually as flat spots between the dermis and epidermis. Those that remain there are more likely to become malignant. Most move into the dermis and become slightly raised. In children, moles may undergo changes resembling cancer but are benign. Malignant melanoma can begin in moles but almost never before puberty. During pregnancy, moles may enlarge and new ones may appear. Moles sometimes disappear with age. The term nevus refers to a congenital skin mark, whereas a mole may develop after birth. Epidermal nevi are usually the same colour as the surrounding skin.

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Moles are the majority of the members of the mammal family Talpidae in the order Soricomorpha. Although most moles burrow, some species are aquatic or semi-aquatic. Moles have cylindrical bodies covered in fur, with small or covered eyes; the ears are generally not visible. They eat small invertebrate animals living underground. Moles can be found in North America, Europe and Asia.

Terminology

Male moles are called boars; females are called sows. A group of moles is called a labor. By the era of Early Modern English the mole was also known in the British Isle as mouldywarp, a name echoed in other Germanic languages such as Norwegian (muldvarper), Swedish (mullvad) and German (Maulwürfe).

Diet

A mole's diet primarily consists of earthworms and other small invertebrates found in the soil. The mole may also occasionally catch small mice at the entrance to its burrow. Because their saliva contains a toxin that can paralyze earthworms, moles are able to store their still living prey for later consumption. They construct special underground "larders" for just this purpose; researchers have discovered such larders with over a thousand earthworms in them. Before eating earthworms, moles pull them between their squeezed paws to force the collected earth and dirt out of the worm's gut. The Star-nosed Mole can detect, catch and eat food faster than the human eye can follow (under 300 milliseconds).

Evolution

Darwin cites moles as an example of mammals that have organs that have become vestigial and are being phased out by natural selection:

The eyes of moles and of some burrowing rodents are rudimentary in size, and in some cases are quite covered by skin and fur. This state of the eyes is probably due to gradual reduction from disuse, but aided perhaps by natural selection. In South America, a burrowing rodent, the tuco-tuco, or Ctenomys, is even more subterranean in its habits than the mole; and I was assured by a Spaniard, who had often caught them, that they were frequently blind. One which I kept alive was certainly in this condition, the cause, as appeared on dissection, having been inflammation of the nictitating membrane. As frequent inflammation of the eyes must be injurious to any animal, and as eyes are certainly not necessary to animals having subterranean habits, a reduction in their size, with the adhesion of the eyelids and growth of fur over them, might in such case be an advantage; and if so, natural selection would aid the effects of disuse. (Charles Darwin, The Origin of Species, The Origin of Species/Chapter V)

Classification

The Talpidae family is divided into 3 subfamilies, 7 tribes, and 17 genera. The genera bolded in the listing below are the ones whose species are called moles:

Pest status

Moles are considered to be an agricultural pest in some countries, while in others, such as Germany, they are a protected species but may be killed if a permit is received. Problems cited as caused by moles include contamination of silage with soil particles making it unpalatable to livestock, the covering of pasture with fresh soil reducing its size and yield, damage to agricultural machinery by the exposure of stones, damage to young plants through disturbance of the soil, weed invasion of pasture through exposure of fresh tilled soil, and damage to drainage systems and watercourses. Other species such as weasels and voles may use mole tunnels to gain access to enclosed areas or plant roots.

Moles burrow in lawns, raising molehills, and killing the lawn, for which they are sometimes considered pests. They can undermine plant roots, indirectly causing damage or death. Contrary to popular belief, moles do not eat plant roots.

They are controlled with traps, smoke bombs, and poisons such as calcium carbide and strychnine.

Other common remedies for moles include cat litter and blood meal, to repel the mole, or flooding or smoking its burrow. There are also devices sold to trap the mole in its burrow, when one sees the "mole hill" moving and therefore knows where the animal is, and then stabbing it. Humane traps which capture the mole alive so that it may be transported elsewhere are also options.

Similar animals

Several groups of animals have a similar burrowing lifestyle, and some have developed close physical similarities with moles, forming good examples of convergent evolution.

Mole-like mammals are found in the family Chrysochloridae (the golden moles) and the family Notoryctidae (the marsupial moles). These are not related to true moles, but like moles they live underground and are insectivorous.

There are also similar-looking rodents called mole-rats. These do live underground, but are herbivorous.

Mole-crickets are large burrowing insects which have strong digging forelimbs remarkably like those of moles.

See also

References

External links

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