Order Insectivora

The Mammals of Texas - Online Edition

ORDER INSECTIVORA:

SHREWS AND MOLES

The name insectivora (insect eater) has reference to the food habits of the group as a whole. Although moles and shrews are not all strictly insectivorous, insects and other small animal life constitute the chief dietary items of most members of the group. Some kinds, the otter shrews of Africa and the star-nosed mole of 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 which they usually excavate for themselves. Correlated with this fossorial habit, the eyes of all moles are very small, in some species actually not opening to the outside, and of little value to them. On the other hand, their senses of touch and smell are highly developed.

Most 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 the 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 the short-tailed shrew, store food for winter use, but this habit is not common. Surprisingly little is 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 less than 2 years, but specific information is lacking.

One species of mole and four species of shrews occur in Texas.

Family Soricidae (shrews)

Southern Short-tailed Shrew, Blarina carolinensis
Elliot’s Short-tailed Shrew, Blarina hylophaga
Least Shrew, Cryptotis parva
Desert Shrew, Notiosorex crawfordi

Family Talpidae (moles)

Eastern Mole, Scalopus aquaticus

KEY TO THE INSECTIVORES OF TEXAS

1.	Front feet broad and paddle-shaped; eyes non-functional: Scalopus aquaticus (eastern mole). Front feet normal, not paddle-shaped; eyes small, but functional: 2
2.	Total number of teeth 30 or 32; ears nearly hidden in the fur; tail short, less than twice as long as hind foot: 3 Total number of teeth 28; ears rather conspicuous; tail more than twice as long as hind foot; total length about 80 mm: Notiosorex crawfordi (desert shrew).
3.	Total number of teeth 30; four upper unicuspids, with only three readily visible in lateral view; color of dorsum brownish or brownish gray: Cryptotis parva (least shrew). Total number of teeth 32; five upper unicuspids, with four 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 but often tinged with brown; cranial breadth usually less than 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 greater than 10.5 mm. Blarina hylophaga (Elliot’s short-tailed shrew).