68 
JOUKNAL OF MAMMALOGY 
All of the mice are interested in little “ferris wheels’’ in which they 
spin and ride by the hour, getting their exercise and much evident 
enjoyment from them. Even the little pocket mice, usually so quiet, 
become enthusiastic, spinning their wheel. 
We have learned much that is new to us of their habits, dispositions, 
tastes, voices, calls, signals, hours of work and play, sleep, nest-building, 
sanitation and general home-making. Their time and manner of molt 
have been carefully noted. Their breeding habits are still to be studied. 
The only trouble is for busy people to get time enough to watch them, 
but there are many who need just such occupation and would greatly 
enjoy it. I hope to see a large number of people started in this kind 
of study, the results of which will be far-reaching in practical knowl- 
edge of our numerous species of small mammals. 
Biological Survey, Washington, D. C. 
THE MAMMALS OF ITASCA COUNTY, MINNESOTA 
By Alvin R. Cahn 
Itasca County, one of the largest of the Minnesota counties, lies in 
the north central part of the state, Koochiching County intervening 
between it and the Canadian boimdary. Sparsely settled, with few 
cities of any size, the county retains a considerable variety of primitive 
qualities, though lumbering years ago and frequent forest fires have 
done much to ruin an otherwise ideal environment. A myriad of lakes, 
countless small streams and sphagnum bogs, hemmed in and surrounded 
by pine woods, however, still shelter and protect an abundance of 
animal life. 
Yet this county, like so many of the unsettled regions of the north, 
is doomed in the not far distant future to undergo great changes. Fur- 
ther Ihmbering, clearing of land, homesteading, and road building will 
open up what is now almost inaccessible territory, and these develop- 
ments will of course exert great influence upon the wild life of the 
region. The transition from the primitive conditions of the woods to 
their present state has led to the total extinction of several mammals, 
and to the reduction of others almost to the point of extermination. 
Further change will stamp out these latter and greatly reduce other 
species. 
