1 
Fes., 1912. MammMats oF ILLINOIS AND WISCONSIN — CorRY. 141 
The amount of damage done depends upon the abundance of the animals 
and is often serious. If the field is small and isolated, the spermophiles 
sometimes collect and destroy almost the whole crop.” (J. c., p. 42.) 
Concerning the habits of this species in Illinois, Kennicott says: 
“Before the production of the young in May or June the old male 
leaves the female, and appears to lead a solitary and more or less 
wandering life, digging a temporary burrow, or occupying a deserted 
one for a few days, wherever he may take up his abode. These summer 
burrows may often be found, and sometimes are of considerable extent; 
several of those which were examined were more than 20 feet in length, 
being simple galleries from six inches to a foot below the surface — 
deeper in sandy soil — opening at both ends, with the nest placed in 
a small side chamber; others were of much less extent, sometimes with 
but one entrance, and sometimes without nests. The winter burrow, 
in which the pair hibernate and the female brings forth her young, is 
deeper and more complicated, having always two entrances, or more. 
In this, in a side chamber of suitable size, excavated above the level 
of the rest of the burrow, is a large spherical nest of soft grass, entered 
by an opening on one side. This nest is sometimes of the size of a 
half bushel, the interior being generally lined with softer material than 
the outside. The young are produced at the end of May or early in 
June. I have observed from five to nine brought forth at a birth and 
I am informed of two instances in which ten were found in a nest; 
but the number is variable, the usual number being six or seven. The 
young at birth are naked, blind and remarkably embryonic. Dr. 
Hoy, who observed them in confinement, says that they have no 
hair on the body before they are twenty days old and that the eyes do 
not open until the thirtieth day. They continue to require the nourish- 
ment and care of the mother for a much longer period than most rodents. 
During the summer they begin to dig shallow burrows and leave her 
before winter, to shift for themselves.” (J. c., pp. 76-77.) 
This species hibernates during the winter. At the approach of 
cold weather it retires into its burrow and remains there in a torpid 
state for several months, or until the return of mild weather in the 
spring. In northern Illinois it generally goes into winter quarters 
late in October and reappears again about the first of April. On 
March 27, 1910, I saw two at Burnside near Chicago, and on March 
28 and 29, 1911, several were seen running about in the same locality. 
On both occasions the weather for several days had been unusually 
warm for the season. 
Hibernation — Hibernation is a term applied by zodlogists to 
express a peculiar condition of torpid sleep in certain animals, which 
