242 



MAMMALS OF AMERICA 



Dental Formula. — Incisors, Li ■ Canines,-— ; Pre- 



I— I '0—0 



molars,"-^; Molars,^-^=i6. 

 0-0' '3—3 



Pelage. — Adults: Sexes identical. Slimmer. Gen- 

 eral color of upper parts grizzled gray and yellowish- 

 brown, lined with black ; underparts. whitish ; tail above, 

 brown, below, whitish. Winter. Grayer and less red- 

 dish-brown. YouNc: Slate or grayish-brown according 

 to age. 



Measurements. — Total length, 5 inches : tail ver- 

 tebrae. .75 inch ; hind foot, .8 inch. 



Range. — Eastern Massachusetts to Minnesota, south 

 to North Carolina, Tennessee, Indiana and Iowa. 



Food. — Stems of grasses, green vegetation, roots. 



Cooper's Lemming Mouse. — Synattomys cooperi 



The Lemming Mice are in appearance inter- 

 mediate between the True Lemmings and the 

 Meadow Mice. The characters outlined above 

 are ample to separate this Mouse from cither of 

 the.'-e two groups. Some of the Lemming Mice 

 range up into Arctic America, but most of the 

 species are found in more temjierate regions. 

 Thirteen species and subspecies are known. 



Lemming Mice may be distinguished from 

 Meadow Mice by their very short tail and 

 grooved front teeth : but the general appearance 



Related Species 

 Baird. Typical animal of the above description. 

 Eastern United States, Massachusetts to Minnesota, 

 south to North Carolina, Tennessee, Indiana and Iowa. 



Quebec Lemming Mouse. — Synaf'tomys fahius 

 Bangs. Smaller than Cooper's Lemming Mouse. 

 New Brunswick, Quebec, Ontario. 



Labrador Lemming Mouse. — Synaftomys iniiuitus 

 iunuitn.<: (True). Grayisli-brown above; beneath, gray; 

 about size of Cooper's Lemming Mouse. Common to 

 Labrador. 



Ball's Lemming Mouse. — Synaptoiiiys dalli Mer- 

 riam. Size large ; coloration above, raw umber mixed 

 with black; beneath grayish-white. Valley of the 

 Yukon, western Alaska. 



of the two animals is so similar that one is often 

 mistaken for the other. Little is known of their 

 habits. Generally speaking, the Lemming Mice 

 are to be found in wet bogs, on the borders of 

 lakes, or about muskeg ponds, although in In- 

 diana they sometimes freqtient stony pastures on 

 hillsides. Cooper's Lemming Mouse is found 

 from Massachusetts to ]\Iinnesota and south to 

 North Carolina. It is fond of using the runways 

 of Meadow Mice and as a consequence is often 

 caught in them. 



LONG-TAILED LEMMING MOUSE 

 Phenacomys longicaudus True 



General Description. — Superficially very much like 

 a long-tailed Meadow Mouse. Head fairly blunt; ears 

 small and not very prominent; body of normal pro- 

 portions ; tail long, almost half total length ; limbs of 

 normal proportions ; feet slender ; general color, bright 

 rusty brown mixed with black; below, white tinged 

 with brown ; pelage of moderate length. 



Dental Formula. — Incisors. -"_'; Canines, 9ziP ■ Pre- 



I— 1 0—0 



molars, "^-^ ; Molars, ^^=16. 



o — o 3 — 3 



Pelage. — Adults : Sexes identical. Seasonal varia- 

 tion slight. Above, bright rusty brown mixed with 

 black ; underparts, white tinged with rusty brown ; 

 hairs on throat white to the roots, hairs of the rest of 

 underparts plumbeous at base; tail uniform chocolate 

 brown; feet brown. Young: Dark gray. 



Measurements. — Total length. 6 inches ; tail ver- 



tebrae, 2.4 inches ; hind feet, .8 inch ; ears, .2 inch. 

 Range. — Coast district of Oregon. 

 Food. — Vegetation and probably a few insects. 



Rel.\ted Species 



Long-tailed Lemming Mouse. — Phenacomys longi- 

 catidtt.s- True. Typical animal as described above. 

 Coastal Oregon. 



Mountain Lemming Mouse. — Phenacomys orophilus 

 Merriam. Tail short; above grayish-brown tinged 

 with yellow, thickly sprinkled with black. Mountains 

 of British Columbia and western United States south 

 to Mt. Shasta. 



Labrador False Vole. — Plienacomys iingava ungava 

 Merriam. Smaller than the Long-tailed Lemming 

 Mouse; face more yellow than rest of body; color 

 pale yellowish cinnamon brown. Labrador. 



The Long-tailed Lemming Mouse belongs to a 

 group very closely related to the Common 

 Meadow Mouse. For a long time naturalists 

 classified them together and this fact gave rise 

 to the name Phenacomys, which means False 

 Mouse. The characters which separate the two 

 are not superficial and can only be determined by 

 careful examination. The best dilTerence is tne 

 fact that the molar teeth of Phenacomys have 



two roots while those of the Meadow Mouse are 

 quite rootless. The Long-tailed Lemming 

 Mouse, however, may be recognized from the 

 fact that it is a tree-loving rodent and lives in 

 the Douglas fir. Bttt the other species are not 

 arboreal and consequently are very easily con- 

 fused with the Meadow Mice. Eleven species 

 and subspecies of this group of Lemming Mice 

 are known. 



