Echigo moles and other digging animals break the soil surface and move as much earth as possible per stroke with short, powerful limbs and sharp claws.

   
  "Quite different in character are the feet of the diggers, animals that habitually burrow into the earth. The friction drag of moving through the ground is potentially enormous, so the size of the limbs and the area through which they move must be kept to an absolute minimum; but at the same time, great strength is needed. The limbs of animals that lead an almost completely subterranean life, like the mole, are short and thick, and their feet are broad and powerful. Each short stroke of a foot must move as much earth as possible, and the mole's feet are spade-like with widely spaced digits. In addition, the claws of digging animals are usually large, sharp and strong, to do the work of a pickaxe in breaking the soil surface. The aardvark of South Africa (its Afrikaans name, 'earth-pig', refers to its rather pig-like head) is a curious animal that digs for food in termite's nests. Its feet are short and massive with large, almost hoof-like claws on each toe. It is said that one aardvark can dig a hole faster than six men with shovels. Not only does it dig into termite nests to eat the insects, the aardvark digs burrows 4m or more in length in which to hide during the day.

The armadillos of Central and South America are also powerful diggers, able to conceal themselves at amazing speed; they too have short, strong legs with daunting claws. The feet of the giant anteater, another excavator of ant and termite nests, are not massive as those of the aardvark. They are long and curved -- so much so that the anteater is forced to walk on the sides of its feet with an ungainly bow-legged gait. The anteater is a scratch-digger, not a maker of burrows, so its claws do not need to be as large." (Foy and Oxford Scientific Films 1982:179-180)
  Learn more about this functional adaptation.

   

The family Talpidae consists of moles and desmans; currently, its approximately 42 species are grouped into 17 genera. Talpids can be found throughout most of North America and Eurasia. Around 2/3 of the members of this family are at least partially fossorial, digging underground tunnels in which they live and forage on subterranean invertebrates (some also eat plant parts). Others are aquatic (desmans) or forage on the surface (Asian shrew-moles, Uropsilus). Fossorial moles have evolved notable specializations for their underground lifestyle. Their bodies are fusiform, the eyes are tiny (and sometimes covered by skin), the legs are short, and external ears are lacking. The forelimbs are rotated such that the elbows point dorsally and the palms of the front feet face posteriorly. This orientation lends power to their digging strokes. In addition, the forelimbs are short and strong and terminate in formidable claws. The fur of moles is velvety and can lie equally well in any direction, which allows easy movement in the burrows backward as well as forwards.

 

Most talpids have a flattened skull with a long and narrow rostrum. Sutures between cranial bones fuse early. The zygomatic arches are complete, and auditory bullae are present. The modifications of the pectoral girdle and forearm to achieve the orientation and power described above are extreme in some species of moles; the humerus, for example, is broader than long and almost unrecognizable due to the elaboration of surfaces for the attachment of muscles. A short and broad clavicle is present.

 

The dental formula of talpids is 2-3/1-3, 1/0--1, 3-4/3-4, 3/3 = 33-44. The molars are dilambdodont.

 

Desmans and some moles are aquatic; that is, they are skilled swimmers that live near the water and eat aquatic invertebrates and small fish that they catch underwater. Desmans have webbed feet and a very unusual flexible snout that is used to probe for food at the bottoms of lakes, streams, or ponds. There are only two species of desmans, one lives in Asia and the other in Europe, and both are endangered.

 

Like shrews, moles have relatively high metabolic rates and insatiable appetites. They are active at all times of the day and night. While they can be found in a wide variety of habitats, they seem to prefer moist soils that are easy to burrow in.

 

Fossil talpids are known from as early as the Eocene.

 

    Technical characters 

   

  References and literature cited: 

 

Nowak, R.M., and J.L. Paradiso. 1983. Walker's Mammals of the World, 4th ed., Vol. I. Baltimore, Johns Hopkins University Press.

 

Gorman, M.L., and R.D. Stone. 1990. The Natural History of Moles. Ithaca, New York, Comstock Publishing Associates.

 

Vaughan, T.A. 1972. Mammalogy. Philadelphia, W.B. Saunders Co.

 

Yates, T. L. 1984. Insectivores, elephant shrews, tree shrews, and dermopterans. Pp. 117-144 in Anderson, S. and J. K. Jones, Jr. (eds). Orders and Families of Recent Mammals of the World. John Wiley and Sons, N.Y. xii+686 pp.