Page:Popular Science Monthly Volume 30.djvu/342

326 acorns, chinkapins, hazel-nuts, and corn; and so there really seems to be no necessity for bush-dwelling mice ever to return to the ground when once they have taken up their quarters in a smilax thicket—that is, return before the winter is over.

In this my experience is quite the opposite to that of others who have found underground retreats beneath the bush-nests, and have seen the mice, when forced to leave the latter, take refuge in them. It is possible, certainly, that these were burrows of the meadow-mouse (Arvicola riparia), and it would be hard to prove, in a meadow everywhere tunneled by mice and shrews, that the presence of burrowings, whether deep or shallow, beneath nests in bushes, was not merely a coincidence; and, again, I am quite sure the same tunnels are often used in common by widely different species of small mammals.

The stores of food for winter use are of much interest as connected with the subject of hibernation; but I can at present merely outline what I have seen, and what conclusions I have reached from such observations. It can be truthfully said that, while the white-footed mouse is not a hibernating animal, nevertheless it frequently hibernates. In other words, its prolonged sleeping, sometimes extending over several weeks, depends not upon the temperature, for I have seen them scampering over the snow when the mercury was nearly at zero, but upon their access to the food they have laid up for winter use. Cut this off and they will not starve, but pass into that curious torpid state which, with many mammals, continues for the entire season. I have experimented so frequently with them in regard to this, that I feel warranted in saying that one wonderful capability of the creature is, to be able to avoid starvation and its attendant horrors by optional hibernation.

Why, it will probably be asked, do so many of these mice quit their cozy quarters in or on the ground, and which have served them every purpose, and take all this trouble to build a new home in the bushes for the winter? It has been suggested that the nest was worn out, and better fitted for entomological research than for hesperomoid habitation. I had myself thought of this, but have never detected such abundant evidences of this disastrous condition as would warrant the removal; and certainly the fur of these creatures would carry, in all cases, a sufficient number of acari to bring about, in a brief space, a repetition of the plague.

The supposed excessive dampness during autumn and winter of many situations where the summer nests of the mice abound has also been urged as a probable reason for the marked exodus that, as we have seen, occurs on the approach of cooler and wetter weather; but the exposure to sudden summer showers would, in this respect, be more objectionable than the steadier rains and gradual melting of snow during winter; when, as a matter of fact, they are less apt to suffer from water encroaching upon their nests than at other times—the frozen condition of the rough surface tending to carry off the water and