Page:Popular Science Monthly Volume 17.djvu/377

Rh perhaps to remote oases and mountain-regions, hundreds of miles away. She-wolves that must have come from Lithuania or eastern Poland have been shot in northern Germany. Under such circumstances topographical instinct becomes a matter of vital importance, and where there is a want Nature always finds the means of supplying it. All our senses are comparatively rudimental. Every organ holds the possibility of an infinite functional development. In man the ability of distinguishing black from white has been perfected into the art of reading, the faculty of identifying at a single glance half a hundred multiform black marks on a white background. By constant practice and hereditary transmission of cumulative acquirements, the ability of remembering the bifurcation of a ravine, or of smelling a muskrat across a creek, was thus, perhaps, developed into the art of recollecting the ramifications of a vast mountain system or of scenting the atmosphere of a given locality athwart a continent.

Similar causes have produced similar results in other species of animals, for the sense of orientation is not confined to the genus Canis. Horses and goats show traces of the same talent; pigeons, crows, falcons, and all migratory birds possess it in a transcendent degree; also all migratory fishes and reptiles, shad, sturgeons, tunny fish, and marine tortoises. Now, there is no doubt that in most birds the olfactory sense is very feebly developed. Eagles, falcons, and sparrow hawks hunt by sight, and even condors and other vultures have been decoyed with sham carcasses, hides stuffed with straw or stones. Pigeons and chickens are very sharp-sighted and awaken at the slightest sound, but a noiseless thief can surprise them in any dark night—the sense of smell does not warn them. Von Haller went so far as to assert that birds can not smell at all, and that their nostrils are only respiratory apertures.

How, then, could carrier-pigeons find their way from Cleveland to Philadelphia? Belgian pigeons have carried letters from Paris to Namur and from Geneva to Brussels, in fourteen and twenty-two hours; and a gerfalcon, which Henri Quatre presented to the commander of a Mediterranean brigantine, returned from Tangier to Paris in a single day. Did they steer by sight? However telescopic their vision might be, the incurvation of the globe would preclude the idea.

The bird-of-passage instinct is much less wonderful. Cranes and geese might steer due south by the aid of the noontide sun, and return by inverting the process till they come in sight of familiar scenery. A Northampton swallow, flying at the rate of two miles a minute, could well afford to roam at random over the State of Massachusetts till she came in sight of the Holyoke range and Mount Tom. A sturgeon, too, might find his spawning-grounds at the mouth of the Ottawa by following the St. Lawrence upward till he reached the Chaudière of St. Anne. In short, the art of retracing a self-chosen route appears much less enigmatical. But even reptiles have crossed