FIELD BOOK OF MAMMALS 



Oregon Dwarf Pocket Rat. — Microdipodops megacephalus 

 Oregon us Merriam. 

 Resembling typical megacephalus, but "tail longer; pelage 

 less fluffy, upperparts more olivaceous and less conspic- 

 uously lined with black-tipped hairs; underparts white — 

 buffy wash less marked; a whitish streak usually present 

 along underside of tail; skull smaller." (Merriam) Total 

 length, 6 inches; tail vertebras, 3.5 inches; hind foot, i inch. 

 Found in the Alvord Desert region, Harney County, Oregon, 

 and Modoc County, California. 



Pale Dwarf Pocket Rat. — Microdipodops pallidus Merriam. 

 "Slightly larger than megacephalus; pelage long, soft, lax 

 and fluffy; tail decidedly longer and without dark tip; body 

 much paler. Color. — Upperparts pale buffy fulvous, finely 

 and inconspicuously lined with dark-tipped hairs; under- 

 parts, including sides of nose, lower sides of face, legs, feet, 

 and underside of tail white; upperside of tail buffy through- 

 out without dark tip." (Merriam) Total length, 6.8 

 inches; tail vertebrae, 4 inches; hind foot, i inch. Found in 

 the region of the Sink of the Humboldt and Carson, Church- 

 ill County, Nevada. 



California Dwarf Pocket Rat. — Microdipodops calijornicus 

 Merriam. 

 Equal to megacephalus in size but with longer tail and hind 

 foot, more compact pelage and snow white head markings 

 and underparts. Upperparts olivaceous finely sprinkled with 

 black; sides of nose, spot over eye, patch back of ear clear 

 white; tail above buffy with blackish near tip, below white; 

 underparts clear white. Total length, 6.4 inches; tail verte- 

 bras, 3.6 inches; hind foot, i inch. Found in Sierra Valley, 

 Plumas County, California. 



Mono Dwarf Pocket Rat. — Microdipodops polionotus Gv'irmeW. 

 Most like pallidus but even paler in color; pelage shorter 

 and less fluffy, smaller and with shorter tail. Upperparts 

 cartridge-buff with faint sprinkling of black-tipped hairs, 

 especially on rump; ashy on sides of face and rump; con- 

 spicuous white spot at base of and behind each ear; 

 underparts clear white in marked contrast to color of sides. 

 Total length, 6 inches; tail vertebrae, 3.3 inches; hind foot, 

 .96 inch. Found in Mono County, California (near Benton 

 Station, alt. 5200 feet). 



Dwarf Pocket Rats are apparently rare and local in distri- 

 bution. There are comparatively few in museum collections 

 and not much has been written about habits. They live in a 

 very restricted section where they seem to prefer arid and 

 desert conditions. These Rats have been found on sandy, 

 sagebrush flats. 



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