INSECTIVORES

 

INSECTIVORES, members of the mammalian order, small animals with several conservative anatomical characteristics. They retain five digits on all limbs and walk or run with soles and heels on the ground (plantigrade). They have flexible snouts and relatively small eyes and ears, sometimes lacking external evidence of either one or both. Most of them are solitary and nocturnal. They are carnivorous and predatory, although not all are exclusively so; many feed also on carrion and some, hedgehogs particularly, take some vegetable matter as well. As their name suggests, most feed on invertebrates primarily. Three families are represented in Persia and Afghanistan: hedgehogs, family Erinaceidae; moles, family Talpidae; and shrews, family Soricidae. (Illustrations, maps of distribution in Persia, and brief species accounts in Persian are to be found in Hušang Ziāʾi’s book; illustrations and species accounts in English are provided by Fred A. Harrington; another Persian summary of the Persian insectivores is in Eskandar Firouz’s work.)

There are four species of hedgehogs in Persia and at least two in Afghanistan (Figure 1; see HEDGEHOG).

Moles (Figure 2). Moles are subterranean mammals with poor vision, but keen senses of smell, hearing, and touch. They feed on earthworms and insect larvae encountered as they burrow just below the surface of the ground. As they tunnel, they hump up the surface into characteristic trailways that mark their passage. They excavate deeper burrows for their permanent habitation, and much of their food is derived from insects that fall into these. Their excavations disturb the soil and the roots of plants, so that they are considered a nuisance by farmers, who do their best to exterminate them. In their natural habitats, such activity is part of the soil cycle that maintains the vegetation of the region, serving to both aerate and irrigate the soil.

Moles are highly specialized for their tunneling life. Their eyes, while structurally complete, are tiny; they have no external ears; their bodies are flattened; their powerful forelimbs are short and paddle-like, turned permanently outward. The fur is free to move in any direction as the mole moves forward or backward through its tight burrows.

Moles have a short breeding season, producing a single litter of two to seven each year. The young disperse from their mother’s territory after weaning, about a month after birth. They begin breeding in the following year. Most moles are solitary and territorial, coming together only during a short period in the spring for mating. The breeding season varies with latitude and perhaps altitude. Due to the secretive and hidden nature of their activities, little is known of the details of the natural history of most species of moles. As is the case for most animals, no life history studies have been carried out on moles in Persia.

Moles are confined to the Northern Hemisphere and probably evolved first in Europe (Gorman). Two species of moles are known from Persia. No moles have been collected in Afghanistan.

Talpa caeca Savi, 1822, Mediterranean mole, found in southern Europe, Turkey, Persia, and the Caucasus. In Persia it is found in the Caspian and Azerbaijan regions. This mole is dark gray to black; the naked nose is pink in life, and the feet are white. It is about 150 mm in total length, the tail about 25 mm. Its strongly reduced eyes often have no external openings. It lives in mature forests and in the scrublands of wild pomegranate along the northwestern beaches of the Caspian Sea (Harrington).

Talpa streeti Lay, 1965, Persian (or Street’s) mole, found in Kurdistan, northwestern Persia. It is slightly larger than the Mediterranean mole but similar in appearance and replaces it at elevations above 2,000 meters, where it inhabits open grassland (Harrington).

Shrews (Figure 3). These are mouse-sized and smaller animals, generally unspecialized in their anatomy, with tiny eyes and reduced external ears. Their senses of smell and hearing are acute. They vocalize in their social interactions, and at least some species may use the voice in echolocation, that is, receiving information about the environment in high-pitched sound reflected back from surrounding objects. Species that have been studied have a life span of only a year to eighteen months. Shrews are voracious feeders and must be active day and night to obtain enough food. They must live in habitats where food is constantly abundant. The saliva of at least some species is venomous, probably an advantage in managing large prey species, for some species of shrews will attack and kill rodents, frogs, and other animals larger than themselves. Although humans have had various reactions to shrew saliva, none has been life-threatening. Shrews forage in leaf litter in woodlands and beneath herbage in grassland and steppes. A few, including one Persian species, are aquatic. Some species dig tunnel systems, the focal points of their territories, while others are often encountered in burrows of voles and other small rodents. Shrews are protected to some degree from predation by a musky smell produced by skin glands so that most carnivores find them unpalatable. Reptilian and avian predators are less deterred.

Shrews may produce several litters in a year, and the gestation period is about two weeks to twenty-four days, depending on the species. The young are born blind and naked but are weaned within two to three weeks. In the genera Suncus and Crocidura, when the young are ready to leave the nest, they form a “caravan,” the first youngster gripping the rump of the mother with its teeth, each of the others similarly grasping the rump of the one in front. Shrews are of some benefit to agriculture where their population densities are high, as they consume vast numbers of insects.

Two subfamilies of shrews recognized are the Soricinae, the red-toothed or “hot” shrews (Sorex and Neomys), and the Crocidurinae, white-toothed or “cold” shrews (Crocidura and Suncus). The Soricinae are called “hot” because they have an extremely high metabolic rate, even for their small size, while the Crocidurinae have a slower metabolism, and, often, a somewhat longer life span. They may even lower their body temperature in response to food deprivation.

Natural history studies of shrews remain to be done in Persia and Afghanistan. What we do know of the ecology and life history of the species that occur in these countries come from a few studies done elsewhere in their ranges. Much of the information presented above is covered at greater length by Margaret A. Kuyper. Information about shrews in Persia has been summarized by Harrington, and Jerry D. Hassinger has recorded information on shrews in Afghanistan.

Shrews are found in Eurasia, Africa, North America, and north of the equator in South America. Nine species of shrews occur in Persia, four of which are also found in Afghanistan.

Sorex minutus Linnaeus, 1766, Eurasian pygmy shrew, found from Europe to the Himalayas, including northern and western Persia. Its habitat in Persia has not yet been well defined. It is distinguished from most other shrews in Persia by its red-tipped teeth.

Neomys anomalus Cabrera, 1907, southern water shrew. Its habitat is southeastern Europe to northern Persia. In Persia it lives in streams in the Caspian region and Azarbaijan. It may also occur in the Zagros Mountains. These red-toothed shrews add fish, amphibians, and crustaceans to their diet of worms and insects. They are adapted to their aquatic life by having long, stiff hairs on the rear feet that add surface area, increase traction, and trap air bubbles that enable them to scamper over the water surface and help them to swim.

Crocidura leucodon (Hermann, 1780), bicolored white-toothed shrew. It is found in southern Europe, the Levant, Turkey, and Persia in the Caspian region and the south side of the Alborz mountains. It lives in moist habitats of mature forests and in meadow or grassland. It is distinguished by its contrasting dark brown back and white under parts.

Crocidura russula (Hermann, 1780), greater white-toothed shrew, western Palearctic, found in central and southern Europe, North Africa, and western Asia, including Persia and Afghanistan. It occurs in north central, northwest, and southwest Persia and in eastern Afghanistan. It inhabits a wide variety of moist habitats in evergreen oak and coniferous forests, meadows, and farmlands, often along irrigation ditches. This is the largest of the Persia-Afghanistan shrew species, up to 95 mm in length. It is uniformly dark gray-brown above and below. Populations from eastern Europe to Persia formerly included in C. russula (Corbet, 1978) have been assigned to C. suaveolens by some workers (Catzeflis et al.).

Crocidura suaveolens (Pallas, 1811), lesser white-toothed shrew, found in southwestern Europe and North Africa to China, Korea, and Taiwan. In Persia it has been found on the northern slopes of the eastern Alborz mountains and on the Turkmen plains. It is also found in northern and western Afghanistan. It inhabits rather dry areas in grassland steppe and mountain valleys, where it prefers vegetation cover of medium to high density.

Crocidura susiana Redding and Lay, 1978, Susian shrew, endemic to southwestern Persia (Ḵuzestān). Nothing is yet known about its natural history. Its taxonomic relationships need further study.

Crocidura zarudnyi Ognev, 1928, “Zarudny’s shrew,” found in eastern Persia and western Afghanistan. This pale-colored shrew inhabits drier desert habitats than other Persian shrews. It is often associated with human habitation and is found in burrows in the sides of buildings and mud walls. It is of benefit in such habitats in that it eats scorpions as well as pest insects. In eastern Afghanistan, a distinct subspecies has been described as Crocidurus zarudnyi streetorum Hassinger, 1970 “Streets shrew.” It probably extends into western Pakistan.

Suncus etruscus (Savi, 1822), Pygmy white-toothed shrew, found from Mediterranean to India and Sri Lanka, including Persia on the Gorgān steppe in fairly dry areas. It is found on the grassy turf and around shrubs in low-lying areas. This is the smallest terrestrial mammal in the world, weighing only 2 grams. Only the extremely rare Kitti’s hog-nosed bat from Thailand is smaller at 1.3-3 grams.

Suncus murinus (Linnaeus, 1766), House shrew, found in southern Asia, from China to East Africa. It is associated with human habitation and thus far, in Persia has only been found in Ḵuzestān and in Afghanistan in the Jalālābād region. It is a large shrew, up to 190 mm total length. It takes food scraps as well as insects.

 

Bibliography:

P. M. Butler, “The Problem of Insectivore Classification,” in Kenneth Allen Joysey and Thomas S. Kemp, eds., Studies in Vertebrate Evolution: Essays Presented to F. R. Parrington, Edinburgh, 1972, pp. 253-65.

F. M. Catzeflis et al., “Unexpected Findings on the Taxonomic Status of East Mediterranean Crocidura russula auct. (Mammalia, Insectivora),” Zeitschrift für Säugetierkunde 50, 1985, pp. 185-201.

Gordon B. Corbet, The Mammals of the Palaearctic Region: A Taxonomic Review, British Museum (Natural History), London and Ithaca, N.Y., 1978.

Idem, The Mammals of the Palaearctic Region: A Taxonomic Review, Supplement, British Museum (Natural History), London, 1984.

E. Dannelid, “The Genus Sorex (Mammalia, Soricidae): Distribution and Evolutionary Aspects of Eurasian Species,” Mammal Review 21, 1991, pp. 1-20.

Eskandar Firouz, Ḥayāt-e waḥš-e Irān/A Guide to the Fauna of Iran, Tehran, 2000, pp. 341-44.

Martyn L. Gorman, “Moles and Desmans,” in D. Macdonald, ed., The Encyclopaedia of Mammals, New York, 1984, pp. 766-69.

I. M. Gromov and G. I. Baranova, eds., Katalog mlekopitayushchikh SSSR (Catalogue of the mammals of the USSR), Leningrad, 1981.

Fred A. Harrington, A Guide to the Mammals of Iran, Tehran, 1977.

Jerry D. Hassinger, “Shrews of the crocidura zarudnyi-pergrisea Group with Descriptions of a New Subspecies,” Fieldiana: Zoology 58/2, 1970, pp. 5-8.

Idem, A Survey of the Mammals of Afghanistan Resulting from the 1965 Street Expedition (Excluding Bats), Fieldiana: Zoology 60, Chicago, 1973.

J. H. Hutchison, “Notes on Type Specimens of European Miocene Talpidae and a Tentative Classification of Old World Tertiary Talpidae (Insectivora: Mammalia),” Geobios 7, 1974, pp. 211-56, pls. 37-39.

Rainer Hutterer, “Order Insectivora,” in D. E. Wilson and D. M. Reeder, eds., Mammal Species of the World: A Taxonomic and Geographic Reference, Washington, D.C., 1993, pp. 69-133.

D. Jammot, “Evolution des Soricidae: Insectivora, Mammalia,” Symbioses 15, 1983, pp. 253-73.

P. D. Jenkins, “Variation in Eurasian Shrews of the Genus Crocidura (Insectivora: Soricidae),” Bulletin of the British Museum (Natural History), Zoology Series 30, 1976, pp. 271-309.

Margaret A. Kuyper, “Shrews,” in D. Macdonald, ed., The Encyclopaedia of Mammals, New York, 1984, pp. 758-63.

Douglas M. Lay, A Study of the Mammals of Iran Resulting from the Street Expedition of 1962-63, Fieldiana: Zoology 54, Chicago, 1967, pp. 1-282.

T. Maddalena, “Systematics and Biogeography of Afrotropical and Palaearctic Shrews of the Genus Crocidura (Insectivora: Soricidae): An Electrophoretic Approach,” in G. Peters, and R. Hutterer eds., Vertebrates in the Tropics, Bonn, 1990, pp. 297-308.

David W. Macdonald, ed., The Encyclopaedia of Mammals, Facts on File Publications, New York, 1984.

R. W. Redding and D. M. Lay, “Description of a New Species of Shrew of the Genus Crocidura (Mammalia: Insectivora: Soricidae) from Southwestern Iran,” Zeitschrift für Säugetierkunde 43/5, 1978, pp. 306-10 (illustration).

C. A. Repenning, “Subfamilies and Genera of the Soricidae,” Geological Survey, Professional Paper 565, 1967, pp. 1-74.

Don E. Wilson and DeeAnn M. Reeder, eds., Mammal Species of the World: A Taxonomic and Geographic Reference, Washington, D.C., 1993.

Hušang Ziāʾi, Rāhnemā-ye ṣaḥrāʾi-e pestāndārān-e Irān, Tehran, 1996.

A. C. Ziegler, “Dental Homologies and Possible Relationships of Recent Talpidae,” Journal of Mammalogy 52, 1971, pp. 50-68.

A. E. Zykov, “Zoogeographic Analysis of the Small Mammal Fauna (Insectivora, Rodentia, Lagomorpha) of Kopet-Dagh Mountain Range,” Vestnik Zoologii 5, 1991, pp. 3-11.

(Steven C. Anderson)

Originally Published: December 15, 2004

Last Updated: March 29, 2012

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