RICE RAT 



coloring above. Color of upperparts grayish brown with- 

 out the wash of tawny or buffy. Total length, 9-1 1 inches; 

 tail vertbrce, 4.3-5.3 inches; hind foot, 1.2 inches. Found 

 "From Corpus Christi Bay north and east along the Gulf 

 coast of Texas and Louisiana to the delta of the Mississippi, 

 thence north in the Mississippi Valley to southeastern Mis- 

 souri ; general range reaching southeastern Kansas, probably 

 by way of the Arkansas River valley through Oklahoma 

 (not yet known from Oklahoma) ; altitudinal range in 

 Austroriparian Zone, mainly below 500 feet; but extending 

 up to about 1,000 feet in Kansas." (Goldman) 

 Rio Grande Rice Rat. — Oryzomys couesi aquaticus (Allen). 

 Large in size; total length, 11. 3-12. 4 inches; tail vertebrae, 

 5.5-7.2 inches; hind foot, 1.3-1.5 inches. Color above, 

 ochraceous buff, paler along sides, below, buffy. Pelage 

 shorter than in the forms of palustris. Found in "Rio 

 Grande Valley, from Camargo, Tamaulipas, to Gulf coast 

 near Brownsville, Texas; altitudinal range from sea level 

 to about 300 feet in Lower Sonoran Zone." (Goldman) 



******* 

 The Rice Rats are a large group of southern distribution. 

 North of the Rio Grande they occur in only a narrow strip 

 along the southern border and north along the Atlantic coast 

 to New Jersey. While they may be locally common within 

 this range, the Rice Rats are not a predominating element in 

 the fauna, as they are in much of their southern range. 



Our Rice Rats may be easily distinguished from other native 

 rodents on the basis of size, pelage, and color. They are larger 

 than any of the common Mice, Peromyscus or Microtus, and 

 may be known from the "Wood Rats by their coarser pelage 

 and smaller size. Rice Rats bear a superficial resemblance to 

 some of the introduced Rats, especially the Roof Rat, but are 

 smaller and have shorter tails. 



These rodents live in grassy localities, marshy meadows, or 

 open brush lands, are prolific breeders, and sometimes are an 

 economic problem in farming districts. The number of 

 young to a litter varies from three to seven but is usually four 

 or five. The first young appear in April or May but there 

 may be a later brood as well. 



Genus Sigmodon^ 



Dentition: Incisors, {\ Canines, g ; Premolars, g ; Molars, f = 16. 



^For a revision of this genus see Vernon Bailey, Proceedings Bio- 

 logical Society Washington, Vol. 15, pp. 101-116, 1902. 



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