38 A. L. V. Manniche. 



and Mustela erminea), this does not at all apply to the parts of 

 Greenland, from which my observations originate. It is true that 

 the animal always led an active existence, but in the hardest winter 

 and particularly in the time of darkness this life was carried on in 

 concealment, chiefly in the system of passages which are made 

 between the layer of snow and the surface of the ground. During 

 the time of absolute darkness traces of lemmings were never ob- 

 served upon the snow. 



As a winter resort the lemming will always choose localities 

 which, besides ofTering sufficient food for it, are provided with a 

 layer of snow thick enough to afford the animal the necessary pro- 

 tection against the hard cold of winter. From this I feel justified 

 to conclude that a winter like 1906—07 must prove fatal to great 

 numbers of lemmings. 



In the before mentioned passages made under the snow, the 

 lemming will be strolling about busily during the winter. Here it 

 finds its food — according to my experiences it is out of the que- 

 stion that a special winter supply may be saved up — and here 

 the animal builds its nests or at least a part of these. The nests 

 built under the snow are disproportionately large, almost globular 

 and made of fine, faded grass which has been gnawed to pieces. 

 Some of the nests found above the ground were carefully lined with 

 musk-ox wool, or in localities where such was wanting, with the 

 long, woolly hairs of the lemming itself. These lined nests looked 

 as if they might have contained young ones. 



Gradually as the earth was bared of snow in the summer time, 

 in certain favourable places, mostly where great masses of snow 

 had been lying, I was able to find great numbers of lemmings nests 

 on the surface of the ground. Immense quantities of the dung of 

 the animals, collected in conical piles or oblong heaps, gave addi- 

 tional proof of where the lemming spends its winter. My attempts 

 of digging lemmings out of the snow лvere ahvays in vain. I was 

 often able to follow the main passage of the animals 15 — 20 meters 

 along the surface of the ground. At last it would end blindly in 

 the snow, if it were not in connexion with some subterranean tun- 

 nel. Such tunnels opened here and there, however, in the super- 

 terrestrial main passage. From the latter several short passages, 

 always finishing blindly in the snow, were emerging on both sides. 

 As a rule the dung of the animals was deposited in these side tun- 

 nels. Sometimes I found, however, a larger heap of dung as well, 

 just inside the main entrance. During my attempts of excavation I 

 never succeeded in coming across a veritable nest; on the other 

 hand I found in several places in the principal passage stalks of 



