Order Soricomorpha

Shrews and Moles

The name Soricomorpha, meaning shrew form, refers to the morphological appearance of the group.  This order previously was treated in the larger, broader context as the order Insectivora, a name primarily referring to the generalized diet of these animals.  The Soricomorpha are restricted to the northern hemisphere (Europe, Asia, northern Africa, and North America), with only a single species occurring in South America.  This is a diverse group with 45 genera and 428 species. 

Although moles and shrews are not all strictly insectivorous, insects and other small animal life constitute the major dietary items of most members of the group.  Some kinds, the otter shrews of Africa and the star-nosed mole of North America, for example, feed also upon fish.  The Townsend mole of the Pacific Northwest often is a nuisance to bulb growers because of its fondness for the bulbs of many kinds of plants. 

Moles, as a group, are subterranean in habit and spend most of their lives in the darkness of underground tunnels that they usually excavate for themselves.  Correlated with this fossorial habit, the eyes of all moles are very small; in some species the eyes actually do not open to the outside and are of little value to the animal.  On the other hand, the senses of touch and smell are highly developed in moles. 

Most North American shrews live on the surface of the ground and occupy burrows only for sleeping or resting.  Most of them have a decided preference for damp or boggy habitats where rank vegetation, surface litter, rocks, or rotting logs afford adequate protection.  Some species, notably Crawford's desert shrew, are adapted to the arid regions of our western deserts.  At the opposite extreme are the water shrew and the marsh shrew, neither of which occurs in Texas. 

Shrews and moles are active throughout the year; the former often tunnel through snow or walk on top of it in search of food.  Some species, notably Elliot's short-tailed shrew, store food for winter use, but this habit is not common.  Surprisingly little in known regarding the habits of many species.  The exact gestation period is not known for most species, and practically nothing is known about the growth and development of the young except that they grow rapidly and reach adult proportions in about 6 weeks.  The length of life of shrews is thought to be <2 years, but specific information is lacking. 

Of the 46 species of shrews and moles in North America, only 5 (about 9%) occur in Texas -- 1 species of mole and 4 species of shrews.  

 

KEYS TO THE SHREWS AND MOLES OF TEXAS

1. Front feet broad and paddle shaped; eyes nonfunctional.  Scalopus aquaticus (eastern mole).

Front feet normal, not paddle shaped; eyes small but functional.................. 2

2. Total number of teeth 30 or 32 (unicuspids 4 or 5); ears nearly hidden in the fur; tail short, less than twice as long as hind foot .................................... 3

Total number of teeth 28 (unicuspids 3); ears rather conspicuous; tail more than twice as long as hind foot; total length about 80 mm.  Notiosorex crawfordi (Crawford's desert shrew). 

3. Total number of teeth 30; 4 upper unicuspids, with only 3 readily visible in lateral view; color of dorsum brownish or brownish gray.  Cryptotis parva (least shrew).

Total number of teeth 32; 5 upper unicuspids, with 4 readily visible in lateral view; color of dorsum dark slate to sooty black or tinged with brown........... 4

4. Restricted to the pine-oak forest and pine forest regions in the eastern one-third of the state; pelage dark gray often tinged with brown; cranial breadth usually <10.5 mm.  Blarina carolinensis (southern short-tailed shrew). 

Known only from three counties in the central and coastal regions of the state; pelage not tinged with brown; cranial breadth usually >10.5 mm.  Blarina hylophaga (Elliot's short-tailed shrew).

 

Family Soricidae

Shrews

Shrews are characterized by their small body size and high metabolic rate.  These traits force them to spend much of their time actively foraging.  They are primarily insectivorous, but they are able and willing to take down whatever small prey they encounter.  Some species have poisonous salivary secretions that help to subdue prey. 

Shrews are nocturnal creatures, and they are usually solitary except during breeding seasons.  Most shrews are terrestrial, although a few species are aquatic, and they are typically found in moist habitats.  Four genera and 39 species are found in North America. 

 

Family Talpidae

Moles

Four genera and seven species of moles are known from North America.  Small creatures with long, tubular bodies, they are well adapted for their burrowing lifestyle.  They lack external ears and have very small eyes, and their limbs are modified for digging. 

All moles are insectivorous.  Their habit of burrowing in lawns and gardens, which has garnered them a reputation as a pest, is probably more often beneficial than harmful, as they aerate and loosen the soil and consume harmful soil insects and grubs.

  

From The Mammals of Texas, Seventh Edition by David J. Schmidly and Robert D. Bradley, copyright © 1994, 2004, 2016.  Courtesy of the University of Texas Press.