Feb., 1912. Mammals or Illinois and Wisconsin — Cory. 249 



The Hudson Bay Jumping Mouse is found within our Hmits from 

 northern IlHnois northward throughout Wisconsin. I have examined 

 specimens from Lake and Jo Daviess counties, IlHnois, and from Vilas, 

 Burnett, Marinette, Pierce, Dodge and Rock counties, Wisconsin. 

 Hollister records it from Racine and Walworth counties (/. c, p. 140), 

 and Jackson from Oneida County, Wisconsin, and it undoubtedly 

 occurs throughout the state. 



This curious Mouse inhabits both fields and woodland and I have 

 seen it in bogs, although on the whole it seems to like brush grown 

 places along fences and bordering timber. It is well named, for, when 

 frightened, it makes a series of surprisingly long jumps, a distance of 

 ten feet at a single leap being by no means unusual, and to a person 

 who sees one of these little animals for the first time, its activity is 

 astonishing. Suddenly from almost under his feet it goes flying through 

 the air, barely touching the ground before it is up again with the seem- 

 ing resiliency of a rubber ball, and the next moment it has disappeared 

 in the bushes. 



It makes a nest in burrows in the ground, under logs, and in hollow 

 trees and stumps. In summer it also constructs a rounded nest which 

 is concealed behind rocks or under bushes and thick grass. These 

 nests are usually about 4 or 5 inches in diameter, the entrance being 

 a hole at one side. The young are from 3 to 6 in number. This 

 species hibernates in winter in this latitude. Preble states that during 

 the cold weather they are generally found singly, although sometimes 

 in pairs, in nests in holes in the ground, which vary from a few inches 

 to three feet below the surface. He says, "They lie rolled up like a 

 ball with the feet close together and the tail curled about them. If 

 removed from the nest and subjected to a moderate degree of heat, 

 they revive and in the course of a few hours move about freely, but 

 generally resume their lethargic state if again exposed to cold. The 

 pulse and respiration are very slow" {I.e., p. 9). He also states that 

 these animals sometimes hibernate in a nest above ground. 



Kennicott says, ''Dr Hoy informs me that when he was a boy, in 

 digging out a rabbit in winter, he found a pair of this species in a state 

 of profound torpor, exhibiting all the phenomena of perfect hibernation. 

 They were in a large nest of leaves situated two or three feet below the 

 surface" {I.e., p. 97). 



An interesting article on the hibernation of the Jumping Mouse in 

 Indiana is given by Professor Sanborn Tenney.* He says, "On the 

 1 8th of January of the present year (1872), I went with Dr. A. Patton 

 of Vincennes, Indiana, to visit a mound situated about a mile or a mile 



* Amer. Nat., VI, 1872, p. 330. 



