Art. II.—True Instincts of Animals.
[Read before the Philosophical Institute of Canterbury, 1st May, 1895.]
The definition of the term “instinct” has been greatly narrowed of late years by scientific thinkers. Formerly, every action of an animal betokening intelligence was attributed to instinct, but latterly the term has been restricted to actions like that of cell-making in the bee, the construction of dams-and canals by the beaver, and so forth-actions which are performed in an apparently, mechanical manner by one generation after another, and seem to be prompted by some other faculty, than intelligence. It is now admitted that many acts done by the higher animals must owe their origin to a faculty akin to, if not identical with, human reason; but the apparently unchanging and invariable nature of such actions as those just mentioned-as the construction of webs by spiders and nests by birds, and the migration of birds-seem to mark off these actions from the variable acts which are done upon the spur of the moment at the bidding of the animal's intelligence.
I think we can restrict the definition still further. Writers upon this subject have not taken sufficiently into account how much the young animal may be taught by the old, and how much it can learn through imitation and from its own observation. The migratory habits of certain birds, for example, are always set down to “instinct”; but birds usually migrate in
flocks, and, in any case, with the young bird it is “follow my leader.” The same remark may be made concerning the migratory habits of the Norwegian lemming, the salmon, and other animals. The periodical shifting of their places of abode by certain animals may be regarded as racial habits, in which the offspring are trained by their parents or seniors; and it is no more necessary to assume the existence of a special faculty to account for the habit than it would be to assume the existence of a special faculty in mankind to account for the custom of some human families to shift periodically from the town to the country.
The nest-building habits of birds may be similarly explained, and even such extraordinary habits as that of the Australian Megapodidæ, which build up immense mounds of vegetable and other matter and deposit their eggs in the middle, leaving them to be hatched by the heat evolved from the fermentation of the decaying mass. One member of this family-the Leipoa ocellata-forms a pile as much as 45ft. in circumference and 4ft. in height of leaves thickly covered with sand. It is assumed that these birds construct the mounds without teaching or knowledge acquired by observation; but I see no warrant for such a belief. How the racial habit was originally acquired is a fair subject for research; but, having once been acquired, and the propensity incorporated (so to speak) in the bird's mental system, it is easy to comprehend how the young megapod may acquire the art of building a mound, either from direct observation or from seeing other birds perform the work.
The beaver's remarkable habits of constructing dams and water-canals, which, if constructed by human beings, would be deemed proofs of considerable engineering skill, illustrate my proposition. The beavers dwell together in families in artificial habitations called “lodges,” which are tenanted by generation after generation. Some of the works constructed by the beaver, too, are of great antiquity, and there is an instance upon record of a beaver-dam which appeared, upon investigation, to be about a thousand years old, and was still in use. The young beaver remains in the parental lodge until the summer of its third year, when it starts housekeeping for itself; so that it has ample opportunity during its residence in the parental domicile for receiving instruction from its elders in the peculiar ways of beaverdom; and when it does begin life upon its own account it still enjoys opportunities of acquiring engineering skill by observing the labours of other beavers, and from its own experience. Probably its earlier works are less perfect than those which it executes when it grows older, just as the nests made by young birds are seldom as perfect as those made by older ones.
Cats and dogs instruct and correct their young; so do monkeys. Tigers and wolves teach their young how to hunt and kill their prey; and, speaking generally, the adult Carnivora train their offspring for the battle of life.
Some of the most remarkable so-called instincts displayed by animals can be accounted for in the same way, and when we come to analyse these instincts we find that they are nothing more nor less than tribal habits, passed on from generation to generation, and acquired in a similar way to that in which the racial habits of mankind are acquired. Let us take for example a singular instinct of the huanaco, or guanaco, a small camel-like animal found in South America. In the southern part of Patagonia there are dying-places of the huanaco, to which all individuals inhabiting the surrounding plains repair at the approach of death in order to yield up the ghost there. “The best known of these dying or burial places,” says Hudson in” The Naturalist in La Plata,” “are on the banks of the Santa Cruz and Gallegos Rivers, where the river-valleys, are covered with dense primeval thickets of bushes and trees of stunted growth. There the ground is covered with the bones of countless dead generations.” “The animals,” says Darwin, “in most cases must have crawled before dying beneath and among the bushes.” This peculiar habit of the huanaco seems to be of a local nature, restricted to South Patagonia. In Northern Patagonia, and on the Chilian and Peruvian Andes, where the huanaco is also found, no such instinct has been observed. Mr. Hudson endeavours to account for the origin of this habit by assuming that, in far distant ages, the huanaco “had formed a habit of congregating with its fellows at certain seasons at the same spot; further, that there were seasons of suffering to the animal- the suffering, or discomfort, or danger, having in the first place given rise to the habit. Assuming, again, that the habit had existed so long as to become a fixed immutable instinct, a hereditary knowledge, so that the young huanaco, untaught by the adults, would go alone and unerringly to the meeting-place from any distance, it is but an easy step to the belief that, after the conditions had changed, and the refuges were no longer needed, this instinctive knowledge -would still exist in them, and that they would take the old road when stimulated by the pain of a wound, or the miserable sensations experienced in disease, or during the decay of the lifeenergy, when the senses grow dim, and the breath fails, and the blood is thin and cold.” Mr. Hudson's theory is a not improbable explanation of the origin of the habit; but it seems to be an unwarranted assumption on his part that the young huanaco, about to die, proceeds to one of these dying-places without being taught by the adults to do so. The huanaco is
a gregarious animal, and usually goes about in small herds, each containing from half a dozen to thirty animals; but Mr. Darwin states that he saw one herd which must have contained at least five hundred huanacos. Inasmuch as the habit in question is only exercised once during the huanaco's life- time, and then just before death, and is not wanted as part of its daily round of occupations, it seems rather far-fetched to suppose that the habit is become so ingrained in the mental constitution of the animal that the memory of it invariably revives upon the approach of death, and leads the animal unerringly to a dying-place. Even if we assume that an irresistible desire to seek for a dying-place Seizes the animal upon the approach of death, it is difficult to understand how the knowledge of the whereabouts of a dying-place could be inherited. It is a far more likely supposition that if a young huanaco is in extremis the older members of the herd expel it from their ranks, as other sick and wounded animals are usually expelled by their fellows, and indicate to it whither it should go.
Traditional and tribal memories, perpetuated by communication from old to young, will account for such habits as the hive-making habits of the bee and the domestic and military habits of the various species of ants, which are so commonly regarded as typical of the more wonderful development of instinct in the lower animals. Even Charles Darwin, calm philosopher as he is, writing about the intelligence of ants, rapturously observes, “The brain of an ant is one of the most marvellous atoms of matter in the world, perhaps more so than the brain of a man.” In point of fact, an ant does not possess a brain, although it does possess an assemblage of ganglia which in the higher animals develope into a brain. The large number of ants and social bees which dwell together in communities, and the rigour of their social organization, make the education of the young ant or bee a matter of comparative ease. It is born into the midst of an active community, living day after day on a system of unchanging routine, and the young ant or bee naturally falls into step with its fellows. A child born and bred in a camp would naturally acquire military habits. The young ant, nevertheless, seems to receive special instruction from, its elders. Romanes, summing up the results of the observations made upon this subject, says, “The young ant does not appear to come into the world with a full instinctive knowledge of all its duties as a member of a social community. It is led about the nest, and ‘trained in a knowledge of domestic duties, especially in the case of the larvæ. Later on the young ants are taught to distinguish between friends and foes. When an ants’ nest is attacked by foreign ants the young ants never join in the fight, but confine themselves to removing the
pupæ; and that the knowledge of hereditary enemies is not wholly instinctive in ants is proved by the following experiment, which we owe to Ford: He put young ants belonging to three different species into a glass case with pupæ of six other species, all the species being naturally hostile to one another. The young ants did not quarrel, but worked together to tend the pupæ. When the latter hatched out an artificial colony was formed of a number of naturally hostile species, all living together after the manner of the ‘happy families’ of the showman.”
Amongst the hive-bees, the younger ones are usually left at home with a small number of older bees to perform the internal work of the hive while the remainder of the older bees, go out to collect honey and bee-bread. What deduction can be drawn from this fact save that the younger bees are gradually trained to a knowledge of their duties as members of the community? Even bees of mature age seem to teach one another. Huber saw a bee building upon, the wax which had already been put together by her comrades. But she did not arrange it properly, or in a way to continue the design of her predecessors, so that her building made an undesirable corner with theirs. “Another bee,” says Huber, “perceived it, pulled down the bad work before our eyes, and gave it to the first in the requisite order, so that it might exactly follow the original direction.”
Of course, the fact that many so-called instinctive acts are really the products of education and experience does not clash with the view that animals may be, and probably are, born into the world with a hereditary predisposition to certain tribal habits which render instruction in the performance of those habits easier and more effective than it would otherwise be, just as some human families are endowed with musical gifts, and the children in such families more readily acquire the technical skill necessary for the efficient exercise of the musical art than children of families destitute of such special gifts. The mental like the bodily structure of any single animal is the sum and outcome of all its progenitors' faculties; and, just as its body is better fitted to perform certain acts than others, so its mental organization is better fitted for certain mental operations than it is for others. Body and mind are correlated, and work in unison. The web-building spiders secrete web-building material in their bodies, and possess highly-specialised organs enabling them to produce the material in such manner and abundance that it can be used in the construction of snares. And, as this specialised anatomical structure has gradually been evolved from simple beginnings, the mental faculty required for the construction of snares has been evolved with it. The spider
may be said to be endowed with mental as well as physical spinnerets. Those oft-repeated acts which are required for the preservation of the animal's life become so interwoven with its mental fabric as to be inseparable from it, and performed almost mechanically. Hence, the newly-born animal, inheriting a special bodily structure, and a mental endowment corresponding with it, is apt and ready to perform such acts even without special education. It may be taken for granted that any human being with his bodily organization intact would in process of time learn to walk of his own accord, even if placed in circumstances which had precluded him from seeing any other human creature walk, or from receiving any instruction in the art of walking.
If we eliminate all such habits as may have been acquired without teaching or observation, we shall find left comparatively few fixed habits of animals which, in the present state of our knowledge, cannot be accounted for by the individual having received instruction from its fellows or gained knowledge from its own observation; and it is to such habits that I propose to restrict the term “instinct.” For the purposes of this paper I will call them “true instincts.” These instincts are confined almost exclusively to insects. By way of illustration I will take the case of the caterpillar of a butterfly (Thekla) referred to in Darwin's “Posthumous Essay on Instinct,” printed as an appendix to Romanes' “Mental Evolution in Animals.” This caterpillar feeds within the pomegranate; but when full-fed gnaws its way out (thus making the exit of the butterfly possible before its wings are fully expanded), and then proceeds to attach with silk threads the point of the fruit to the branch of the tree, so that it may not fall before the metamorphosis of the insect is complete. Hence, the larva works on this occasion for the safety of the pupa and of the mature insect which it will never see; and there is apparently no means by which it can receive instruction, since no visible intercourse takes place between the butterfly which laid the eggs from which the caterpillar is produced and the caterpillar. When considering this problem we must firmly grasp the fact that, although the caterpillar, the pupa, and the mature insect—the butterfly—are, to outward seeming, three distinct animals, in reality they are but varying phases of the same animal; just as the infant, the boy, and the man are one and the same human being, but in different stages of existence. The difference in the outward aspect of the insect in the several phases of its existence is indeed the more striking, but the essential facts of the phenomenon are the same. The caterpillar, the pupa, and the imago form the various stages of the insect's life-cycle, just as the progress from early infancy to old age forms the life-
cycle of the human being. Therefore, if it be the case that the insect possesses the power of inheriting memories, we can understand how the memory of an inherited habit, useful and common to one phase of the animal's existence, may readily be transmitted from the perfect insect to its offspring through the various stages of that offspring's existence. The order in which these memories are transmitted will be the order in which they will manifest themselves in the new life-cycle. The question therefore is, Does the Thekla possess the power of transmitting the memory of that habit to which I have referred? Is it possible for a habit like this to become so ingrained in the mental constitution of the insect as to be capable of transmission from parent to offspring, in like manner to that in which the bodily structure is transmitted? It appears not unreasonable to suppose that such may be the case. The life of an insect is short and monotonous, and its range of locomotion limited. Its world is a small world—a fragment of the larger world in which man lives and moves and has his being; there is little scope for variation of habit, and the insect's habits of life must consequently tend to become stereotyped. Therein it differs from the higher animals, whose mental powers are kept active and mobile by being constantly exercised upon fresh subjects. As the mental nature of the animal grows more complex, instincts become more rare, because the animal exercises more choice in its actions. Even the minds of human beings, however, when kept within too narrow grooves, are apt to become largely mechanical in their actions, as is evidenced by certain Eastern nations, which follow the same habits and customs as were followed by their forefathers thousands of years ago. If, then, any particular habit became stereotyped upon the animal's mental system (of course, I use the term “stereotyped” in a strictly metaphorical sense, and for the purpose of rendering my meaning clearer) it would be transmitted from generation to generation in the same manner as the other mental qualities of the race were transmitted; for, whatever view we may take of the nature of mind, it cannot be denied that animals of the same race exhibit similar mental capacities; and hence we must conclude that the offspring owes its mental constitution to its parents just as much as it owes its bodily constitution to them, although the environment of any individual may develope mental as well as bodily peculiarities in that individual. Nor would the fact that the Thekla butterfly is the offspring of two parents affect the matter, because the habit or instinct above mentioned is common to both, and hence would be transmitted by both.
The fact that the nervous system of the Invertebrata is fundamentally different from that of the Vertebrata is full of
significance when we reflect that true instincts are almost confined to members of the former branch of the animal kingdom, seeing that it is through the nervous system that the mind of the animal finds expression.
Amongst true instincts I should class such acts of protective mimicry as those performed by the Phasmidæ. Here is a description by Professor Drummond of one of these creatures found by him in tropical Africa: “Take two inches of dried yellow grass-stalk, such as one might pluck to run through the stem of a pipe; then take six other pieces nearly as long and a quarter as thick; bend each in the middle, at any angle you like; stick them in three opposite pairs, and again at any angle you like, upon the first grass-stalk, and you have my Chirombo. When you catch him his limbs are twisted about at every angle, as if the whole were made of one long stalk of delicate grass, hinged in a dozen places, and then gently crushed up into a dishevelled heap. Having once assumed a position, by a wonderful instinct he never moves or varies one of his many angles by half a degree. The way this insect keeps up the delusion is indeed almost as “wonderful as the mimicry itself; you may turn him over and over and over, but he is mere dried grass, and nothing will induce him to acknowledge the animal kingdom by the faintest suspicion of spontaneous movement.” We know too little of the life-history of the Phasmidæ to assert positively that their practice of shamming death (which is Drummond's interpretation of their action, or rather inaction) is not taught the young by the adults, but it seems improbable. The insect has inherited its peculiar bodily structure from its ancestors, and this structure readily lends itself to the practice. The instinct seems to be brought into play not only in the presence of actual danger, but also as a precaution against possible danger; and it may be that it is done unconsciously, like those reflex actions so common amongst the higher animals, many of which seem to be relics of what were manifestations of active intelligence in the past, but are now become mechanical responses to outward stimuli. Moreover, we must not forget that some animals of low organization are of an extremely lethargic disposition, and will remain motionless for hours, or even longer periods—our New Zealand tuatara may be taken as an instance—and it is possible that the “mimicry” of Professor Drummond's “Chirombo” may be partly attributable to this cause.
We may also class as indications of true instincts the fear which young animals, including children, usually manifest towards what is really dangerous to them. Young children, for example, usually show signs of fear on being plunged into the sea. The late Dr. Romanes once turned loose a ferret into
an outhouse which contained a doe rabbit with a very young family. The doe left the young ones, and the latter, as soon as they smelt the ferret, began to crawl about in so energetic a manner as to leave no doubt that the cause of the commotion was fear, and not merely the discomfort arising from the temporary absence of the mother. This fear is not, however, universal amongst young animals, as is proved by the result of some experiments recently made by Professor Lloyd Morgan, and related by him in Nature (11th October, 1894). He put some young pheasants, about a day old, which had been artificially hatched out of the egg by means of an incubator, in close proximity to a fox-terrier; but, although the dog was keen to get at them, and trembling with excitement in every limb, the young birds exhibited no signs of fear. They also showed no fear of a large blindworm, but pecked at its forked tongue, its eye, and tail. Mr. Douglas Spalding made a number of interesting experiments upon the young of our domesticated animals, the result of which he published in Macmillan's Magazine, which went to show that chickens, young ducks, and pigs, and other newly-born animals, are capable of performing many acts apparently betokening intelligence without instruction. He found that very young chickens were able to pick up small specks of food and scrape in search of food; that newly-born pigs sought- the mother's teat almost immediately after birth; and that, on placing four ducklings a day old in the open air for the first time, one of them almost immediately snapped at and caught a fly on the wing: all of the experiments being conducted in such a manner as to preclude the possibility of the young animal having learned to do these things by imitation. In considering these experiments, however, it must be borne in mind, as I have pointed out in my treatise on “The Intelligence of Animals,” that the young fowl, duck, or pig comes into the world with its intelligence pretty fully developed—although it afterwards gains wisdom from experience—and all such acts as those just mentioned are intelligent acts, not acts performed in an unvarying fashion, but acts varying with the surrounding circumstances. There seems, indeed, nothing more remarkable in a chicken scraping up the ground in search of food than in its walkiing, and chickens do not require to be taught how to walk.
What I have denominated true instincts suggest an analogy with reflex actions. Herbert Spencer, indeed, regards instinct as compound reflex action, by which I understand him to mean a sequence of reflex actions manifested in immediate succession to one another; while Dr. Romanes regards such socalled instincts as the hive-making instinct of the honey-bee as being reflex actions into which is imported the element of consciousness. It seems to me, however, that singleness is of
the very essence of a reflex action: the action may be complex in its manifestation, but it is essentially one act; while “consciousness” and “reflex action” are contradictory terms. An action is styled “reflex” because it is performed without consciousness on the actor's part. Moreover, a reflex action is unchanging in its' manifestation. Let the stimulus be applied and the appropriate and responsive movement follows-automatically. Now, even such apparently fixed habits as the hive-making habit of the bee vary with circumstances, and in some countries the hive-bee abandons its usual practice of collecting honey altogether. In like manner, birds often change the structure of their nests to suit localities, while the migratory habit is sometimes lost. Beavers, suffering from man's persecution, have been found to cease building dams, and to become solitary in their mode of life. The supposed analogy between what are commonly called instincts and reflex actions therefore fails; nor will it hold as respects true instincts, since the latter generally involve a succession of acts directed towards a fixed end, and I see no ground for assuming that these acts are not consciously performed by the animal. It may further be observed that, whereas true instincts are seldom met with outside the Insecta, reflex actions are exhibited by all classes of animals, including man himself.