THE FAMILY OF JUMPING MICE 



{Zapodidw) 



UMPING Mice have several strong marks of distinction which enable even the 

 ordinary observer to separate them from all other rodents. They are slender 

 and graceful Mice with exceptionally long tails, short fore legs, extremely long 

 hind legs which have given them their other name of Kangaroo Mice, and 

 cheek pouches. Probably no other family of animals has more evident peculi- 

 arities. Like the Kangaroo, their muscular hind legs give them remarkable 

 jumping powers, while their tails aid to balance them and give them direction. 

 This family of rodents have the upper incisors compressed. The premolars 

 are small, and the molars rooted. The hind foot has five separate toes. The 

 tail, which is longer than the body, is slender and scantily haired. The family 

 is widely distributed over North America, there being twenty-one species and 



subspecies, found from Canada to North Carolina, and westward to the Pacific Coast. 



JUMPING MOUSE 

 Zapus hudsonius { Zlinmermann) 



Other Name.— Kangaroo Mouse. 



General Description. — A medium-sized Mouse with 

 rather harsh pelage and e.xtremely long hind legs and 

 tail. Head of normal proportions; nose pointed; ears 

 small : body inclined to be thick-set ; tail slender, taper- 

 ing and sparsely covered with hair; hind feet enor- 

 mously elongated ; toes five in number on both fore 

 and hind feet ; pelage rather harsh because of the long, 

 somewhat cciarse, outer hairs. Hibernates in .winter. 



Dental Formula.— Incisors, ^0^ ; Canines, ~ ; Pre- 



inolars, ]f-\ \ Molars, f^=i8. 



Pelage. — .Adults: Sexes identical. Seasonal varia- 

 tion occurring but not especially conspicuous. Above, 

 strong ochraceous yellow mi.xed with blackish along the 

 dorsal line ; sides a brighter yellow ; underparts and feet 

 white, meeting the color of sides in a sharp line ; tail 

 above, dark, beneath, whitish ; pelage composed mainly 

 of a shorter coat with many long, coarser hairs. 

 Young : Like adults but lacking the well-defined dorsal 

 band of blackish mixed with ochraceous. 



Measurements. — Total length about 8 inches ; tail 

 vertebrae, about 5 inches; hind foot, 1.2 inches. 



Range. — From southern Hudson Bay region south 

 to New Jersey and North Carolina, west to Iowa and 

 Missouri, and northwest to ."Maska. 



Food. — Green vegetation. 



Remarks. — The only members of their family found 

 in North America, the Jumping Mice are so well char- 

 acterized as to need a critical comparison with no other 

 Mice. Twenty-one species and subspecies are found in 

 North America. Differentiation has taken place along 



the lines of color variation and size differences as well 

 as in cranial structure. The group is a semi-boreal one, 

 that is to say, it is found only in the mountains, in the 

 higher latitudes, or in regions with climate temperate 

 or colder. It is not known south of the United States. 



REL.VTEn Species 



Jumping Mouse. — Zafus liudsoiiius liiidsouins 

 (Zimmermann). Typical animal of the above descrip- 

 tion. From southern shores of Hudson Bay south to 

 New Jersey, and in the mountains to North Carolina, 

 west to Iowa and Missouri, and northwest to Alaska. 



American Jumping Mouse. — Zaf^us hudsonius aincr- 

 icaiiiis (liarton). Smaller. From Raleigh, North Caro- 

 lina, to southern Connecticut and lower Hudson Valley 

 along the coastal plain. 



Great Plains Jumping Mouse. — Zapus hudsonius 

 caiiiprstris Preble. Size large. Great Plains from 

 Manitoba to Nebraska, and westward to Colorado and 

 Wyoming. 



Rocky Mountain Jumping Mouse. — Zapus princcps 

 princcps .\llen. Size large, color yellowish-brown 

 instead of ochraceous-brown. Rocky Mountain region 

 from Northern New Mexico to Alberta. 



Pacific Jumping Mouse. — Zapus pacificits Mer- 

 riam. Size large, coloration very bright. Interior 

 valleys of southwestern Oregon and northwestern 

 California. 



Woodland, or Canada Jumping Mouse. — Napaeo- 

 zapHS insignis iiisignis (Miller). Lacks the premolars 

 found in true Zapus: size large; coloration pale; tail 

 white tipped. Eastern Canada south to western Mary- 

 land. 



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