328 The Naturalist in La Plata. 



and would form new habits to meet the new danger. 

 One would be that at the approach of a period of 

 deep snow and deadly cold, all the herds frequent- 

 ing one place would gather together at the most 

 favourable spots in the river valleys, where the vege- 

 tation is dense and some food could be had while the 

 surrounding country continued covered with deep 

 snow. They would, in fact, make choice of exactly 

 such localities as are now used for dying places. 

 There they would be sheltered from the cutting 

 winds, the twigs and bark would supply them with 

 food, the warmth from a great many individuals 

 massed together would serve to keep the snow par- 

 tially melted under foot, and would prevent their 

 being smothered, while the stiff and closely inter- 

 laced branches would keep a roof of snow above 

 them, and thus protected they would keep alive 

 until the return of mild weather released them. In 

 the course of many generations all weakly animals, 

 and all in which the habit of seeking the refuge at 

 the proper time was weak or uncertain in its action 

 would perish, but their loss would be an advantage 

 to the survivors. 



It is worthy of remark that it is only at the 

 southern extremity of Patagonia that the huanacos 

 have dying places. In Northern Patagonia, and on 

 the Chilian and Peruvian Andes no such instinct 

 lias been observed. 



