160 



Kansas Academy of Science. 



THE COMMON MOLE. 



Runway Studies ; Hours of Activity. 



By Theo. H. Scheffer, U. S. Biological Survey. 

 RUNWAY STUDIES. 



THE central part of a mole's system of runways can usually be 

 located by the little piles of earth thrust up from the deeper 

 tunnels. These are easily distinguishable from any elevations of 

 the surface ridging due to the mole's burrowing just beneath the 

 sod. They may be looked for on the higher spots of an open field 

 or where natural objects offer some concealment and shelter. 

 There are no "mole hills" in this country, such as those referred 

 to in discussions of the European mole. The deeper tunnels con- 

 stitute the real living quarters of the mole, the surface ridges be- 

 ing merely the paths ranging over his hunting grounds. 



I have at various times spent many hours in digging out mole 

 runways in places that promised interesting results. In all I have 

 thus excavated parts of six central systems and prepared several 

 diagrams, one of which accompanies this paper. In mapping out 

 the runway of any burrowing animal my plan for securing accu- 

 racy of detail is to divide all the ground covered by the excavation 

 into small squares by stakes and cross lines. Corresponding 

 squares, on a smaller scale, are then drawn on the sheets of paper 

 to be used for the map. 



Runways of the common mole. 



The galleries and highways of the central system of a mole's 

 habitation run at depths of from eight or ten inches in some places 

 to twelve or fifteen in others, rarely deeper. In several instances, 

 however, I have found the blind runs, or "bolt runs" as the Eng- 

 lish call them, descending to a depth of two feet or even more. 



