HOW MANY SENSES HAVE ANIMALS?

Otago Witness, Issue 1640, 28 April 1883, Page 26

HOW MANY SENSES HAVE ANIMALS?

Human being have five senses 5* in other words, external objects affect a man's consciousness, and furnish elements of knowledge, in five different ways— by sight, hearing, taste, touch and smell. There are, of course, exceptions to the rule, but the exceptions are all on one side. No one has more than these five senses ; but there are, unhappily, instances of defect, persons of whom, whether dating from birth or later, Milton's pathetic description of his own case ib true—" Knowledge at one entrance quite shut out."

Again, men and races of men are not all upon the same level in regard to the degree of perfection in which they possess these faculties. Nor, indeed, is that degree constant throughout the life of an individual. Perhaps no two persons see precisely alike, and everyone knows what changes the faculty of vision undergoes as life advances. The cultivation, too, of any faculty makes a vast difference. What education of touch, for instance, is required in the accomplished pianist ! The faculty of hearing is capable of remarkable rapidity of operation. Ib is stated on good authority that the ear, in a high state of cultivation, can distinguish sixteen sounds in one second.

When we turn from man to the rest of the animal world we find not only individual variation as to the degreo of perfection of the faculties, but differences also between species as to the attainable degrees of perfection. We find, too, in regard to each sense considered by itself the human faculty is often far inferior to the corresponding faculty iv other orders of creation, though these may be in the scale of being very far below man. We find, moreover, species in which one or more of the senses are totally absent. Do we, on the other hand, find any indications of another sense, or other senses, over and above those which we ourselves enjoy? Lot ub notice some illustrations of the state-

* Wfc leave out of view tho bo-nvllud "mujculw gens?."

ments just made before proceeding to answer this question.

We find, then, that the endowments of each species are adapted to its mode of existence. Those faculties are bestowed upon tho living being which are necessary and useful to it,. No othera are given. This is a very important remark, furwesee the evidence of creative purpose not o.ily in the bestowal of faculties, but also in the withholding of them. A useless faculty, that is one whioh could not be used, would.not only be an encumbrance, it would be a source of positive misery. Suppose, for example (and if chance ruled the world, such cases might well exist), that a creature like the brown fresh water polype (or Hydrafusca), which passes its life attached to a piece of stick or other object, were possessed of eyes. Since it does not possess the power of moving from the spot, they would be of no service to it in the search for food, while they would render its want of locomotion a source ef distress, whether it desired to draw near to an observed bon marcemu, or to escape from a supposed' danger. A conspicuous'example of the combination of far-reaching vision with the power of rapid locomotion is furnished by birds. The vulture is said in poetry to " scent the battle from afar," aud " wheresoever the carcasß is, there," we read, "will the eagles be gathered together." But it is not by the sense of smell that the flight of birds of prey is directed. It is by a piercing sight which, if we did not sea proofs of its existence, would appear incredible. It is this power of far-reaching vision that explains the sudden appearance of gulls in the track o£ the fishennan'B boat after he has thrown overboard the portions of captured fish which cannot serve to bait hia lobster-pots.^ A more agreeable picture and pleasaMer thoughts are suggested in connection with "he same subject, the distant vision of many birds when we hear the lark's song high in the heavens, bo high that we strain our eyes in vain to find his whereabouts, and he is, so far as ■ our powers are concerned, only an "unbodied joy-

That little invisible songster, while he is flooding the heaven and the earth with his joyous strain, is probably watching the home of his affections below, and his heart is brimming over with grateful exultation so long as the foot of no spoiler or destroyer wanders near it* The oxtraordinary power of smell possessed by dogs is so well known that little needs to be said about it here. Perhaps the most remarkable exercise of it is seen when a dog comei suddenly across a line of scent, and after a little investigation backwards and forwards, is able to determine in which direction the unseen animal has gone. This judgment can only be based upon the fact that in one direction he finds the scent grow weaker the further he proceeds while in the other direction it grows stronger.' But that there should be any appreciable difference is almost inconceivable, when wa consider how short the interval of time must have been in which the scent waßlaid along the whole line investigated by the dog, in proportion to the length" of time, perhaps several hours, which may have since elapsed. The dog is not the only animal that excels us in regard to this faculty. Even the horse satisfies himself by means of it as to the wholesomeness or toothsomenessof the foodplaced before him. This is his motive for that preliminary movement which he makes before beginning t« feed, burying his nose in the hay or grain, and stirring it up from the bottom. And if he has more than will satisfy his immediate, wants, ha will show a certain daintiness of appetite. Guided by the Bcent, he will choose one kind of herb and reject another. Houzeau* tells us that he left a rich of hay for the use of his horses during a short absence, and on his return found great holeß in it, where the horses had thrust in their heads to get at their favourite herbage. , Nor is it only among creatures that walk th« ground that we find remarkable power of scent. The lobster is guided by it under the wat r for a distance of a hundred yards, while the scent-laden zephyr, breathing .from a group of newly opened flowers, will draw the bee for a distance considerably exceeding a mile. " Certainly the sense of touch neither in the human hand, nor in the more finely endowed human tongue, which, as we all know, immediately detects a minute foreign body in our food, is comparable to that of the insect's proboscis, or of the antennae, whether of insects or of the lobater tribe. The antenna is indeed a magnificent instrument of touch. The millers thumb is famous for its power of examining the fineness of the products of hiß mill, but where is the human member that can enable its owner to distinguish between one leaf or petal and others that nearly resemble them ? The insect uses its antennas to acquire the same sort of information about objects that we acquire by feeling them with our fingers. While, however, in regard to the sense of touch or smell, and of the minute vision of near objp.cts, the insect tribe presents instances of marked superiority,it is to be noted that some of these tribes, as well as many tenants of the water, are devoid of hearing. In higher orders of life, amongst birds and quadrupeds, to Bay nothing of fishes, a faculty of hearing is often found surpassing our own in regard both to range or distance and to compass, or the capacity to receive impressions from sounds too shrill for human perception. Here, however, we are on ground so familiar that we may pass on without further comment.

Many feats of so extraordinary a nature have been and are continually performed by animals, that the question has been seriously debated whether the performers had not some faculty totally different in kind from any that we possess. On this question, and the most probable answer to it, we can here make but a few brief remarks.

The Oxford and Cambridge boat-race attracts many thousands to the banks 'of the Thames, and that contest of strength, skill, *j# endurance is deservedly interesting. Alm3flk immediately after it is known whether the dark or the light blue has won, there is a flight of carrier-pigeons like rockets up into, the air, which, after tracing one or two ' circles at a great elevation, dash right away to their respective destinations, sometimes many miles distant. Many of us remember the 'services rendered by the pigeon-post in the last sad siege of Paris — how these trusty messengers formed the regular means of communication from Tours, from Bordeaux, from Lyons, to the beleaguered city. How could they find their way ? They could net know thp ground. They did not return to Paris on the same line a3 they had travelled from it, in a balloon it might be, without any opportunity of taking notes of the country traversed.

More extraordinary instances are on record Thus it is matter of history that a falcon belongs to Henry IV. of France, having made its escape from Fontainebleau, arrive the following day in Malta at the very spot where it had been reared.

Perhaps the half-yearly flight of the migrant birds is even more wonderful. How do they find their way from Africa, say, to the particular spot in England where their home has been in the year preceding ? Now there used to be a short and simple

"•The proßont writer desires to expifess'his acknowledgment ol the help doirlved from this sevant's work.

answer to these and many similar questions, which is no longer satisfactory. Instinct was supposed to account for everything that every animate did. But after all instinct is not irrational, however destitute of reason in the general sense an animal may be. Consequently attempts have been made to give a less vague and more rational answer to the questions. A particular use of faculties may be instinctive, but we want to know what faculties are exercised. Two answers have been proposed. One is that there is some mysterious faculty of which we have not even the rudiments, and by means of which birds, dogs and other beings find their way over unknown ground, by means of which some animals seem prescient of earthquakes, or changes in the weather. If this supposition were accepted as true, we should be really no further forward than wh«n everything was referred to instinct. It would be merely a confession that no explanation of facts is possible at all. But we are not reduced to this alternative. It is quite conceivable, and it SBema most probable, that these wonderful performances are achieved by the mere use of the known five senses singly or in combination, these being of such acuteness as to take cognisance of indications which would be unperceived by us. We cannot now state all the reasons for this conclusion. It must suffice to recall to mind the fact that for men living a free open life, as the American Indians do, the contrast between the human and the aininal faculties is not nearly so great as for us whose senses, in regard to the matters under consideration, have been dulled by our in-door life, who tind our way about along well-defined directions— i.e., by roads, lanes, or streets— and who in consequence have no occasion to employ and develop extraordinary sensitiveness as tothe very faint atmospheric and other indications which guide the bird over the pathless deep, and through the trackless sky, and by means of which the Bavage passes with unerring directness from one camp to another, many miles away, through vast forests or over bare mountains, where no sign-posts are provided.— Home Magazine.