The gauchos of the pampas, however, give _a reason_ for the powerful smell of the male deer; and, after some hesitation, I have determined to set it down here, for the reader to accept or reject, as he thinks proper. I neither believe nor disbelieve it; for although I do not put great faith in gaucho natural history, my own observations have not infrequently confirmed statements of theirs, which a sceptical person would have regarded as wild indeed. To give one instance: I heard a gaucho relate that while out riding he had been pursued for a considerable distance by a large spider; his hearers laughed at him for a romancer; but as I myself had been attacked and pursued, both when on foot and on horseback, by a large wolf-spider, common on the pampas, I did not join in the laugh. They say that the effluvium of C. campestris is abhorrent to snakes of all kinds, just as pyrethrum powder is to most insects, and even go so far as to describe its effect as fatal to them; according to this, the smell is therefore a protection to the deer. In places where venomous snakes are extremely abundant, as in the Sierra district on the southern pampas of Buenos Ayres, the gaucho frequently ties a strip of the male deer's skin, which retains its powerful odour for an indefinite time, round the neck of a valuable horse as a protection. It is certain that domestic animals are frequently lost here through snake-bites. The most common poisonous species--the Craspedo-cephalus alternatus, called _Vivora de la Cruz_ in the vernacular--has neither bright colour nor warning rattle to keep off heavy hoofs, and is moreover of so sluggish a temperament that it will allow itself to be trodden on before stirring, with the result that its fangs are not infrequently struck into the nose or foot of browsing beast. Considering, then, the conditions in which C. campestris is placed--and it might also be supposed that venomous snakes have in past times been much more numerous than they are now--it is not impossible to believe that the powerful smell it emits has been made protective, especially when we see in other species how repulsive odours have been turned to account by the principle of natural selection. After all, perhaps the wild naturalist of the pampas knows what he is about when he ties a strip of deer-skin to the neck of his steed and turns him loose to graze among the snakes. The gaucho also affirms that the deer cherishes a wonderful animosity against snakes; that it becomes greatly excited when it sees one, and proceeds at once to destroy it; _they say,_ by running round and round it in a circle, emitting its violent smell in larger measure, until the snake dies of suffocation. It is hard to believe that the effect can be so great; but that the deer is a snake hater and killer is certainly true: in North America, Ceylon, and other districts deer have been observed excitedly leaping on serpents, and killing them with their sharp cutting hoofs. CHAPTER XII.