1322 JOURNAL, BOMBAY NATURAL HIST. SOCIETY, Vol. XXI. 



No. VI.— THE HABITS OF VOLES. 



Where voles of the genus Microtus are common in Kashmir and 

 Himalayas, a curious phenomenon is revealed, on the melting of the snow, 

 which covers their burrows in winter, in the long tortuous ridges of clay 

 left lying on the surface of the ground. These ridges, often some yards in 

 length, are solid throughout, more or less cylindrical, and from 2 to 3 

 inches in diameter in section. As often as not they are unconnected at 

 their extremities with the entrance holes of the voles. The rough sketch 

 below will perhaps explain my meaning better than the description, viz : — 



C3 



A friend who had also noticed and taken an interest m these curious 

 ridges informed me that he had once found them in the melting snow on a 

 hillside, running through the snotv and not in contact with the ground though 

 close above it. This discovery shed some light on what was a perplexing 

 puzzle, and led to the formation in my mind of the following vague theory 

 of their origin, one which however does not altogether satisfy me. 



If any of our readers can enlighten me with the true and scientific 

 explanation I shall feel indebted to him or them. 



I imagine then that, when their burrows are buried deep in snow, 

 these voles abandon their usual habits of burrowing connecting passages 

 underground (such passages being likely to collapse when the snow melts, 

 and thus to lead to flooding of burrows), and construct instead passages 

 along the surface of the ground and through the snow. But, in order that these 

 passages may be kept dry and warm, earth is pvished up into the snow to 

 form a roof above and possibly walls along the same, the earth for this pur- 

 pose being excavated and brought from the holes, as no trench is ever 

 apparent under the ridges in question or connecting the holes. When the snow 

 melts on a slope these ridges can rarely, owing to force of gravity, be de- 

 posited on the ground vertically below the position they occupied in the 

 snow, and must therefore often come to rest some little way down hiU. 



