250 



MAMMALS OF AMERICA 



RED-BACKED MOUSE 

 Evotomys gapperi (I'igors) 



Other Name. — Red-backed Vole. 



General Description. — A small, dark-colored Mouse, 

 reddish along the back. Nose somewhat pointed : ears 

 fairly large ; body of normal proportions, neither slim 

 nor thick-set; tail short, only about one-quarter total 

 length ; legs short ; general color, chestnut along back, 

 with buffy sides and underparts gray ; hair rather long 

 and quite soft. 



Dental Formula 



molars 



Inc 



Canines, 



Pre- 



Molars, ^^=i6. 



3—3 



o — o 



Pelage. — .-Xdults: Sexes identical. Suiiiiiwr. A 

 broad dorsal stripe extending from neck to tail, chest- 

 nut mixed with black ; sides buffy ochraceous ; under- 

 parts pale buff with the hairs dark plumbeous at base; 

 feet silvery-gray ; tail above, brownish, beneath, grayish- 

 buff, tip black. Winter. Colors paler everywhere. 

 Young : Slaty-gray and lacking a pronounced dorsal 

 stripe. 



Measurements. — Total length, 5.2 inches ; tail ver- 

 tebrae, 1.4 inches; hind foot, .7 inch. 



Range. — Massachusetts, New Jersey and Pennsyl- 

 vania northward, and from Atlantic Coast westward 

 to Rocky Mountains in Canada. 



Food. — Inclined to be omnivorous but feeding largely 

 on seeds, berries, roots and bark of trees and shrubs. 



Remarks. — Twenty-three species and subspecies are 

 known, but all conform to the general type described 

 above. 



Rel.'^ted Species 



Red-backed Vole. — Evotomys gapperi gapperi (Vig- 

 ors). Typical animal as described above. Massachu- 

 setts, New Jersey and Pennsylvania northward, and 

 from Atlantic Coast westward to the Rocky Mountains 

 in Canada. 



Rhoads's Red-backed Vole. — Ez'otoniys gapperi 

 snturutiis Rhoads. Larger and longer tailed. Blue 

 Mountains of Oregon, mountains of northern Idaho 

 and northward into British Columbia to Caribou Lake. 



Great Plains Red-backed Vole. — E'Z'otoiuys gappiri 

 loriiuii Bailey. Size very small, colors bright. Tim- 

 bered valleys along edge of plains in Minnesota and 

 eastern Dakotas. 



Dawson's Red-backed Vole, or Arctic Red-backed 

 Vole. — li'^-olniiiys da'a'soni dan'soui Alerriam. Size 

 large ; tail short ; bright rusty red above. Finlayson 

 River and Fort Laird west to Yakutat and Juneau, and 

 north along tlie coast to Prince William Sound. 



Labrador Red-backed Vole. — Evotomys protons 

 Bangs. Size large; sepia above; below, light smoke- 

 gray ; total length nearly seven inches. Labrador. 



The Red-backed Vole may be easily dis- 

 tinguished, in the case of adult animals, from the 

 more common Aleadow Mouse by the broad, 

 chestnut-colored stripe extending along its back 

 the entire length. It is also a smaller animal, 

 with softer quality of fur and larger ears. How- 

 ever, it is a very close relative of the Meadow 

 Mice. This group is of northern distribution, 

 most of the species being found only in the 

 mountains or in high altitudes. 



In many regions the Red-backed Mouse is the 

 most abundant of mammals. It is fond of mossy 

 places, and is capttired more frequently under 

 decayed logs than in any other situation. 



Capper's Red-backed Mouse, of which there 

 are more than half a dozen varieties, is the spe- 

 cies most common in the Eastern States, from 

 Pennsylvania and New Jersey northward to 

 Canada. In the Hudson Bay region, around 

 Fort Churchill, Mr. Edward A. Preble found 

 mossy spruce woods to be its favorite habitat, 

 although he trapped it also in mixed woods, and 

 occasionally in willow thickets in swamps. 



Rhoads's Red-backed Vole is a larger and 

 longer-tailed variety. It lives in the sphagnum 



bogs of the Northwest, which are frozen for 

 several inches below the surface in the winter ; 

 hence it must subsist on the food it has stored 

 in its underground galleries. It is a hardy and an 

 active animal. 



The Dawsou Red-backed Mouse is a hand- 

 some species ranging from northwest Territory 

 west to Juneau. About Great Bear and Great 

 Slave lakes, Preble fotmd some of these animals 

 " living among the rocks on the semi-barren 

 tracts near the shore and feeding largely on the 

 cranberries." Mr. \\'ilfred H. Osgood, who 

 traversed the whole length of the Yukon river 

 in 1899. says: "Red-backed Mice are by far 

 the most abundant mammals in the Yukon 

 region. Specimens were trapped in all sorts of 

 localities ; along cold streams, imder logs, in 

 heavy moss, in Microtus runways, and among 

 rocks. We occasionally saw them during the 

 day, and often heard them rustling the dead 

 leaves on the ground about us as we lay in our 

 blankets at night. They are the vermin of the 

 miner's larder, and are always to be found about 

 log cabins." 



