SHREW

any of the 290 species of mammals of the family Soricidae, order Insectivora. For ordinal relatives with this name, see elephant shrew; otter shrew. See also tree shrew. For rat shrew, see gymnure. Soricids, the true shrews, are mouselike creatures found throughout the Northern Hemisphere and in mountains of northwestern South America; a few have reached oceanic islands, chiefly by human agency. Shrews have tiny eyes and small, external ears. The skull is narrow, and the snout overhangs the lower lip. The 26 to 32 teeth are permanent from birth; the incisors are long and hook tipped. All shrews are small: Savi's pygmy shrew (Suncus etruscus) of the Mediterranean region and Africa to Malaya is perhaps the world's smallest mammal, with head and body length of 3.5 centimetres (1.5 inches) and a 2.5-cm tail (minimum measurements of adult male, Italy); it may weigh only 2 grams (about 0.07 ounce)less than a U.S. dime. The American pygmy shrew (Microsorex hoyi) and the European pygmy shrew (Sorex minuta) are only a trifle larger. Shrews are chiefly terrestrial, living among ground litter; some are burrowers, and a few are semi-aquatic or arboreal. They are active day and night, with regular periods of rest. Shrews feed mainly on invertebrates and help to control noxious insects; some also eat plant material or carrion. A number of species have toxic saliva (painful to humans) for quelling prey. A shrew has a high metabolic rate and may consume more than its own weight in food daily; it cannot live more than a few hours without eating, and in the absence of normal prey it turns cannibal. Shrews have 2 to 10 blind, naked young in one or more litters toward the end of the female's brief life (about 18 months). Few mammals will eat shrews, because many species have glands on the flanks that emit a disgusting scent; however, birds of prey and snakes will feed on them. A shrew may die from the shock of a rough touch or a loud noise. The 40 species of the genus Sorex are found in North America (chiefly) and Eurasia. Examples are the common shrew (S. araneus) of Eurasia and, across northern North America, the common, or masked, shrew (S. cinereus) and the northern water shrew (S. palustris). From the eastern United States to the Andes are the 25 species of Cryptotis. The largest genus is Crocidura, the 160 species of musk shrews, which have a strong odour. If disturbed, the young may form a chain, each holding the tail of the one ahead in its mouth, with the mother as the forward anchor. The biggest species, the Goliath shrew (Crocidura goliath; sometimes Praesorex goliath) of Africa, is 37 cm long, including its 10-cm tail. Musk shrews range from Europe and Africa to the Philippines. Of similar range are the 20 species of thick-tailed shrews (Suncus); they, too, have the chain-forming habit. The two armoured, or girder-backed, shrews (Scutisorex) of the Ituri Forest of central Africa have supernumerary and enlarged lumbar vertebrae; from these arise, uniquely, a mesh of interlocking spines. Thus armoured, the animal can support the weight of a person.