500 



REPOET OF STATE GEOLOGIST. 



and dry oatmeal wei'e favorites. Among wild fruits none were 

 eaten so greedily as the berries of the buck-bush {Symplwricarpos 

 symphoricarpos) . These berries are here the most important single 

 article of diet for these mice in winter and also are eaten exten- 

 sively by other mammals as well as by birds. Acorns were also 

 readily eaten. Seeds of the redbud {Cercis), the wahoo {Euony- 

 mus) , and the bittersweet (Celastrus) were eaten only when the 

 articles of food above mentioned were lacking. Seeds of the 

 scarlet sumac (Rhus glabra) were rejected entirely. 



"A female with three young ate her offspring soon after being 

 put in the cage, but the old one lived for several months. At one 

 time, during my absence, she was without food, but ate the paste- 

 board box which served her for a home ; she must have subsisted 

 on this for at least a week. 



"Two were taken about an old pond shortly after a period of 

 exception all}^ heavy rainfall. At this time salamander eggs had 

 been deposited in abundance around the edges of ponds and the 

 receding water left many of them stranded on the bank. The 

 stomachs of both of the white-footed mice taken at this place con- 

 tained some gelatinous matter which I could not positively identify, 

 but which resembled the coating of salamander eggs more closely 

 than any other substance apt to be found in such a place." 



The nest is often made in a woodpile, although it is also placed 

 under ground at times. It is composed of bark, small twigs, dry 

 grass or leaves and lined with some kind of soft material. In con- 

 struction it is very compact and resembles a bird's nest. Not in- 

 frequently an old bird's nest is used as a basis, and the mouse mere- 

 ly remodels and covers it. 



The young are usually four or five in number, though sometimes 

 as few as two or as many as six. They are naked and helpless 

 when born, but grow rapidly and mature in about three months. 

 Several litters ar(^ born each year, though I am unable to say how 

 many. 



After all our studies, we really know very little about the life 

 history of our smaller mammals. ITovv long do they live, provided 

 they do not meet a violent death? If any die of old age, how are 

 their last days spent? Tlow are the offspring trained in the mat- 

 ters of food getting and nest building? These are some of the ques- 

 tions still uiuinswered for most of the smaller species. I have but 

 a single observation on the life cycle of PcromyHcus. On March 15 

 at Mitchell I saw a white-fooled mouse come out of a woodpile in 

 llie br-igiit iighl of midday and walk slowly a,Fid ])ainfully toward 



