THE MIGRATIONS OF MAMMALS. 253 



of the possibility of subsistence, but also of all hope, or at least of 

 all presence of mind. 



It is under circumstances such as these that the field-voles of 

 our own country, and the Siberian voles, assemble in enormous 

 multitudes, leave their native haunts and migrate to other dis- 

 tricts, turning back for no obstacles, avoiding the water as little as 

 the forbidding mountains or the gloomy forest, fighting to the last 

 against hunger and misery, but perishing hopelessly from diseases 

 and epidemics which rage among them like plagues, reducing armies 

 of millions to a few hundreds. Thus, too, the squirrels of Siberia, 

 which, in ordinary years, undertake, at the most, only short excur- 

 sions, assemble in vast armies, hurry in troops or companies from 

 tree to tree, in compact masses from forest to forest, swim across 

 rivers and streams, throng into towns and villages, lose their lives 

 by thousands; but suffer no obstacle or hindrance — not even the 

 most obvious dangers — to delay them or divert them from their 

 path. The soles of their feet become worn and cracked, their nails 

 ground down, the hairs of their usually smooth fur rough and 

 matted. Through the forest lynxes and sables, in the open fields 

 gluttons, foxes and wolves, eagles, falcons, owls and ravens follow 

 them closely; pestilence claims more victims from their ranks than 

 the teeth and claws of beast of prey or the guns and cudgels of 

 men, yet they press on and on, apparently without hope of return. 

 A Siberian sportsman of my acquaintance gave me a verbal account 

 of the appearance of such an army of squirrels, in August 1869, in 

 the town of Tapilsk, among the Ural Mountains. It was only one 

 wing of a migrating army, pf which the main body travelled 

 through the forest about five miles farther north. Sometimes in 

 single file, sometimes in companies of varying strength, but in 

 unbroken succession, the animals pressed on, crowding as densely 

 through the town as through the neighbouring forest; used the 

 streets, as well as the hedges, and the roofs of buildings as paths; 

 filled every court-yard, thronged through windows and doors into the 

 houses, and created quite an uproar among the inhabitants — much 

 more among the dogs, which killed thousands of them, evincing an 

 unbridled bloodthirstiness till then unsuspected. The squirrels. 



