Horse and Man. 357
stant use, or the slow cumulative process of natural selection, has served to develop a keenness of sense almost preternatural. The vulture's eye, with all the advantage derived from the vulture's vast elevation above the scene surveyed, is not so far-reaching as the sense of smell in the pampa horse. A common phenomenon on the pampas is a sudden migration of the horses of a district to some distant place. This occurs in seasons of drought, when grass or
water fails. The horses migrate to some district where, from showers having fallen or other circumstances, there is a better supply of food and drink. A slight breeze blowing from the more favoured region, which may be forty or fifty miles away, or even much further, is enough to start them off. Yet, during the scorching days of midsummer, very little moisture or smell of grass can possibly reach them from such a distance.
Another phenomenon, even more striking, is familiar to every frontiersman. For some reason, the gaucho horse manifests the greatest terror at an Indian invasion. No doubt his fear is, in part at any rate, an associate feeling, the coming of the Indians being always a time of excitement and com-motion, sweeping like a great wave over the country; houses are in flames, families flying, cattle being driven at frantic speed to places of greater safety. Be this as it may, long before the marauders reach the settlement (often when they are still a whole day's journey from it) the horses take the alarm and come wildly flying in: the contagion quickly spreads to the horned cattle, and a general stampede ensues. The gauchos maintain that the horses smell
358 The Naturalist in La Plata.
the Indians. I believe they are right, for when passing a distant Indian camp, from which the wind blew, the horses driven before me have suddenly taken fright and run away, leading me a chase of many miles. The explanation that ostriches, deer, and other fleet animals driven in before the invaders might be the cause of the stampede cannot be accepted, since the horses are familiar with the sight of these animals flying from their gaucho hunters.
There is a pretty fable of a cat and dog lying in a dark room, aptly illustrating the fine senses of these two species. "Listen! I heard a feather drop!" said the dog. "Oh, no!" said the cat, "it was a needle; I saw it." The horse is not commonly believed to have senses keen as that, and a dog tracing his master's steps over the city pavement is supposed to be a feat no other animal can equal. No doubt the artificial life a horse lives in England, giving so little play to many of his most important faculties, has served to blunt them. He is a splendid creature; but the noble bearing, the dash and reckless courage that distinguish him from the modest horse of the desert, have not been acquired without a corresponding loss in other things. When ridden by night the Indian horse--and sometimes the same habit is found in the gaucho's animal--drops his head lower and lower as the darkness increases, with the danger arising from the presence of innumerable kennels concealed in the grass, until his nose sweeps the surface like a foxhound's. That this action is dictated by a powerful instinct of self-preservation is plain; for, when I have attempted to forcibly drag the animal's head up, he has answered such an
Horse and Man. 359