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 
has been observed. 
