16 



NORTH AMERICAN FAUNA 66 



Sorex cinereus cinereus Kerr 



/Sorex arcticus cinereus Kerr, The animal kingdom . . ., p. 206, 1792. 

 Type locality. — Fort Severn, Ontario, Canada. 



General distrihution. — This is a wide-ranging subspecies, distributed over 

 much of the northern part of North America. In the eastern United States it 

 ranges throughout New England, New York, and western Pennsylvania, and 

 south in the Appalachian Mountains to North Carolina. 



Distribution in Maryland. — Kidge and Valley, and Allegheny Moun- 

 tain sections. (See fig. 4.) 



Distinguishing characteristics. — Teeth 3/1, 1/1, 3/1, 3/3, = 32; third 

 unicuspid usually larger than, or equal in size to, fourth unicuspid; 

 size very small; snout elongated and pointed; tail long, slightly less 

 than half the total length of the animal; ears short and hidden in fur; 

 coloration in winter pelage dark brown to almost black on upper parts, 

 lighter brown or grayish on underparts; in summer, coloration is some- 

 what lighter and more brownish. 



Measurements. — An adult female from 9 miles east of Oldtown, 

 Allegany County, measures: Total length 88; tail 40; hind foot 11; 

 ear 7 ; condylobasal length of skull 15.7 ; cranial breadth 7.4; inter- 

 orbital breadth 2.3; maxillary breadth 3.9; crown length of upp-^r 

 toothrow (exclusive of first incisors) 5.4. 



Habitat and habits. — This shrew is most common around rocks in 

 moist or damp coniferous or deciduous woods. Sometimes it lives in 

 grassy bogs and swamps, but rarely if ever in dry fields or woods 



The nest is located on or near the surface of the ground, in a cavity 

 under a log, rock, or other object. It is composed mainly of leaves, and 

 in shape resembles a flattened sphere some 3 inches in diameter. In 

 its ramblings this shrew utilizes surface runways that it constructs 

 itself and subterranean runways that have been dug by mice. 



The masked shrew is a voracious eater and consumes a wide variety 

 of foods. These include beetles, moths, caterpillars, bugs, flies, crickets, 

 spiders, worms, and the flesh of mice and other shrews. It also eats 

 some vegetable matter such as moss and seeds. 



Little is known of the breeding habits of the masked shrew. The 

 breeding season may extend from March to September, and as many 

 as three litters may be produced in a single season. The gestation period 

 is probably about 18 days, and from 4 to 10 young are produced per 

 litter, the usual number being 7. The male stays with the female before 

 and after pregnancy and during the early development of the young. 

 A young shrew is able to shift for itself within 20 to 25 days after its 

 birth. 



The shrew is physically strong for its size, but being extremely active 

 it seems to bum itself out at an early age. Its longevity is probably 

 not over 2 years if it is allowed to live its full life span. 



