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 frequenting one place would gather together at the most favourable spots in the river valleys, where the vegetation 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 partially melted under foot, and would prevent their being smothered, while the stiff and closely interlaced 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.
CHAPTER XXII.
THE STRANGE INSTINCTS OF CATTLE.
MY purpose in this paper is to discuss a group of curious and useless emotional instincts of social animals, which have not yet been properly explained. Excepting two of the number, placed first and last in the list, they are not related in their origin; consequently they are here grouped together arbitrarily, only for the reason that we are very familiar with them on account of their survival in our domestic animals, and because they are, as I have said, useless; also because they resemble each other, among the passions and actions of the lower animals, in their effect on our minds. This is in all cases unpleasant, and sometimes exceedingly painful, as when species that rank next to ourselves in their developed intelligence and organized societies, such as elephants, monkeys, dogs, and cattle, are seen under the domination of impulses, in some cases resembling insanity, and in others simulating the darkest passions of man.
These instincts are:--
(1) The excitement caused by the smell of blood, noticeable in horses and cattle among our domestic animals, and varying greatly in degree, from an