58 Order INSECTIVORA 



species has a range that appears to be discontinuous, fig. 43. One 

 part of the range apparently extends from Maryland to south- 

 western Mississippi and northern Florida; another part includes 

 areas in Illinois, Indiana, Kentucky, and Tennessee. 



MICROSOREX HOYI (Baird) 

 Pigmy Shrew 



Description. — The pigmy shrew is probably the smallest 

 American mammal. An adult weighs only 2 to 3 grams (less 

 than yi ounce) ; it would take 8 of these shrews to equal the 

 weight of a white-footed mouse, 400 to equal the weight of a 

 fox squirrel, and several thousand to equal the weight of a 

 bobcat. This shrew is a uniform light brown on the upper parts 

 and slightly paler brown on the lower parts. 



Length measurements (based on one Illinois specimen) : head 

 and body 1% inches (48 mm.) ; tail li/^ inches (29 mm.) ; over- 

 all 3 inches (77 mm.); hind foot }i inch (9.5 mm.). 



The skull is similar in many details to that of the southeastern 

 shrew and that of the masked shrew, but it is smaller; it has 

 only three readily discernible unicuspids on each side of the up- 

 per jaw, fig. 44c; the first and fifth are minute. Dental for- 

 mula: I 3/1, C 1/1, Pm 3/1, M 3/3. 



Life History. — Little is known about the pigmy shrew, since 

 it is very rare. The only known Illinois specimen was taken in 

 the middle of the winter of 1949 (Sanborn & Tibbitts 1949) in 

 a garage in Cook County. A masked shrew was found with it, 

 and possibly both shrews were forced there because of a heavy 

 coating of ice out-of-doors. 



Apparently the pigmy shrew inhabits dry woodlands, thickets, 

 and grassy clearings, where it feeds largely on insects. 



Si^ns. — Inasmuch as the pigmy shrew is similar to the two 

 preceding species of Sorex in body form and habits, its signs 

 are probably also similar. 



Distribution. — The only specimen of the pigmy shrew re- 

 corded for Illinois is from Palatine, in Cook County. It belongs 

 to the subspecies Alicrosorex hoyi hoyi (Baird). The range of 

 the species includes most of Canada and Alaska except the West 

 Coast. It extends into the United States as far as northern 

 Illinois, eastern Ohio, and down the Appalachians to North 

 Carolina, fig. 43. 



