The meeting of two previously unacquainted fighting-fish begins with a mutual “showing-off”, a swaggering act of self-display in which every luminous colour-spot and every iridescent ray of the wonderful fins is brought into maximum play. Before the glorious male, the modestly garbed female lowers the flag—by folding her fins—and, if she is unwilling to mate, flees immediately. Should she be willing to mate, she approaches the male with shy insinuating movements, that is to say, in an attitude directly opposed to that of the swaggering male. And now begins a love ceremonial which, if it cannot compare in grandeur with the male war-dance, can emulate it in grace of movement.
When two males meet face to face, veritable orgies of mutual self-glorification take place. There is a striking similarity between the war-dance of these fish and the corresponding ceremonial dances of Javanese and other Indonesian peoples. In both man and fish the minutest detail of every movement is laid down by immutable and ancient laws, the slightest gesture has its own deeply symbolic meaning. There is a close resemblance between man and fish in the style and exotic grace of their movements of restrained passion.
The beautifully refined form of the movements betrays the fact that they have a long historical development behind them and that they owe their elaborateness to an ancient ritual. It is, however, not so obvious that though in man this ritual is a ceremony which has been handed down from generation to generation by a thousand-year-old tradition, in the fish it represents the result of an evolutional development of innate instinctive activities, at least a hundred times older. Genealogical research into the origin of such ritual expression, and the comparison of such ceremonies in related species are exceedingly illuminating. We know more of the evolutionary history of these movements than of all other instincts.
After this digression, let us return to the war-dance of the male fighting-fish. This has exactly the same meaning as the duel of words of the Homeric heroes, or of our Alpine farmers which, even to-day, often precedes the traditional Sunday brawl in the village inn. The idea is to intimidate one’s opponent and at the same time to stimulate oneself to a state of fearlessness. In the fish, the long duration of these preliminaries, their ritual character and above all their great show of colour finery and fin development which at first only serve to subdue the opponent, mask, for the uninitiated, the seriousness of the situation. On account of their beauty, the fighters appear less malevolent than they really are and one is just as loth to ascribe to them embittered courage and contempt of death as one is to associate head-hunting with the almost effeminately beautiful Indonesian warriors. Nevertheless both are capable of fighting to the death. The battles of the fighting-fish often end in the death of one of the adversaries. When they are stimulated to the point of inflicting the first sword-thrust, it is only a matter of minutes till wide slits are gaping in their fins, which in a few more minutes are reduced to tatters. The method of attack of a fighting-fish, as of nearly all fish that fight, is literally the sword-thrust and not the bite. The fish opens its jaws so wide that all its teeth are directed forwards and, in this attitude, it rams them, with all the force of its muscular body, into the side of its adversary. The ramming of a fighting-fish is so strong and hard that its impact is clearly audible if, in the confusion of the fight, one of the antagonists happens to hit the glass side of the tank. The self-display-dance can last for hours but, should it develop into action, it is often only a matter of minutes before one of the combatants lies mortally wounded on the bottom.
The fights of our European sticklebacks are very different from those of the Siamese fighting-fish. In contrast to the latter, the stickleback, at mating time, glows not only when it sees an opponent or a female, but does so as long as it is in the vicinity of its nest, in its own chosen territory. The basic principle of his fighting is, “my home is my castle”. Take his nest from a stickleback or remove him from the tank where he built it and put him with another male and he will not dream of fighting but, on the contrary, will make himself small and ugly. It would be impossible to use sticklebacks for exhibition battles as the Siamese have done, for hundreds of years, with fighting-fish. It is only when he has founded his home that the stickleback becomes physically capable of reaching a state of full sexual excitement; therefore, a real stickleback fight can only be seen when two males are kept together in a large tank where they are both building their nests. The fighting inclinations of a stickleback, at any given moment, are in direct proportion to his proximity to his nest. At the nest itself, he is a raging fury and with a fine contempt of death will recklessly ram the strongest opponent, or even the human hand. The further he strays from his headquarters in the course of his swimming, the more his courage wanes. When two sticklebacks meet in battle, it is possible to predict with a high degree of certainty how the fight will end: the one which is further from his nest will lose the match. In the immediate neighbourhood of his nest, even the smallest male will defeat the largest one, and the relative fighting potential of the individual is shown by the size of the territory which he can keep clear of rivals. The vanquished fish invariably flees homeward and the victor, carried away by his successes, chases the other furiously, far into its domain. The further the victor goes from home, the more his courage ebbs, while that of the vanquished rises in proportion. Arrived in the precincts of his nest, the fugitive gains new strength, turns right about and dashes with gathering fury at his pursuer. A new battle begins, which ends with absolute certainty in the defeat of the former victor, and off goes the chase again in the opposite direction. The pursuit is repeated a few times in alternating directions, swinging to and fro like a pendulum which at last reaches a state of equilibrium at a certain point. The line at which the fighting potentials of the individuals are thus equally balanced marks the border of their territories. This same principle is of great importance in the biology of many animals, particularly that of birds. Every bird lover has seen two male redstarts chasing each other in exactly the same manner.
Once on this borderline, both sticklebacks hesitate to attack. Taking on a peculiar threatening attitude, they incessantly stand on their heads and, like Father William, they do it again and again. At the same time they turn broadside on towards each other and each erects threateningly the ventral spine on the side nearer his opponent. All the while they seem to be “pecking” at the bottom for food. In reality, however, they are executing a ritualized version of the activity normally used in nest-digging. If an animal finds the outlet for some instinctive action blocked by a conflicting drive, it often finds relief by discharging an entirely different instinctive movement. In this case, the stickleback, not quite daring to attack, finds an outlet in nest digging. This type of phenomenon, which is of great theoretical interest both from the physiological and psychological point of view, is termed in comparative ethology a “displacement activity”.
Unlike the fighting-fish, the sticklebacks do not waste time by threatening before starting to fight, but will do so after or between battles. This, in itself, implies that they never fight to a finish, although from their method of fighting, the contrary might be expected. Thrust and counter-thrust follow each other so quickly that the eye of the observer can scarcely follow them. The large ventral spine, that appears so ominous, plays in reality quite a subordinate role. In older aquarium literature, it is often stated that these spines are used so effectively that one of the fighters may sink down dead, perforated by the spine of his opponent. Apparently the writers of these works have never tried to “perforate” a stickleback; for even a dead stickleback will slip from under the sharpest scalpel before one is able to penetrate its tough skin, even in places where it is not reinforced by bony armour. Place a dead stickleback on a soft surface—which certainly offers a much better resistance than water—and try to run it through with a sharp needle. You will be surprised at the force required to do so. Owing to the extreme toughness of the sticklebacks’ skin, no serious wounds can be inflicted in their natural battles which, as compared w
ith those of the fighting-fish, are absurdly harmless. Of course, in the confined space of a small tank, a stronger male stickleback may harry a weaker one to death, but rabbits and turtle doves, in analogous conditions, will do the same thing to each other.
The stickleback and the fighting-fish are as different in love as they are in fight, yet, as parents, they have much in common. In both species, it is the male and not the female that undertakes the building of the nest and the care of the young, and the future father only then begins to think of love when the cradle for the expected children is ready. But here the similarities end and the differences begin. The cradle of the stickleback lies, in a manner of speaking, under the floor, that of the fighting-fish above the ceiling: that is to say, the former digs a little hollow in the bottom and the latter builds his nest on the surface of the water; the one uses, for nest construction, plant strands and a special sticky kidney secretion, the other uses air and spittle. The castle-in-the-air of the fighting-fish, as also that of his nearer relations, consists of a little pile of air bubbles, stuck closely together, which protrudes somewhat over the water surface; the bubbles are coated with a tough layer of spittle and are very resistant. Already while building, the male radiates the most gorgeous colours, which gain in depth and iridescence when a female approaches. Like lightning, he shoots towards her and glowing, halts. If the female is prepared to accept him, she demonstrates it by investing herself with a characteristic, if modest, colouring consisting of light grey vertical stripes on a brown background. With fins closely folded, she swims towards the male who, trembling with excitement, expands all his fins to breaking point and holds himself in such a position that the dazzling brilliance of his full broadside is presented to his bride. Next moment he swims off with a sweeping, gracefully sinuous movement, in the direction of the nest. The beckoning nature of this gesture is at once apparent even when seen for the first time. The essentially ritual nature of this swimming movement is easily understood: everything that enhances its optical effect, as the sinuous movements of the body or the waving of the tail fin, is exaggerated in mimic, whereas all the means of making it mechanically effective are decreased. The movement says: “I am swimming away from you, hurry up and follow me!” At the same time, the fish swims neither fast nor far and turns back immediately to the female who is following but timidly and shyly in his wake.
In this way the female is enticed under the bubble nest and now follows the wonderful love-play which resembles, in delicate grace, a minuet, but in general style, the trance dance of a Balinese temple dancer. In this love dance, by age-old law, the male must always exhibit his magnificent broadside to his partner, but the female must remain constantly at right angles to him. The male must never obtain so much as a glimpse of her flanks, otherwise he will immediately become angry and unchivalrous; for standing broadsides means, in these fishes as in many others, aggressive masculinity and elicits instantaneously in every male a complete change of mood: hottest love is transformed to wildest hate. Since the male will not now leave the nest, he moves in circles round the female and she follows his every movement by keeping her head always turned towards him; the love-dance is thus executed in a small circle, exactly under the middle of the nest. Now the colours become more glowing, more frantic the movements, ever smaller the circles, until the bodies touch. Then, suddenly, the male slings his body tightly round the female, gently turns her on her back and, quivering, both fulfil the great act of reproduction. Ova and semen are discharged simultaneously.
The female remains, for a few seconds, as though benumbed, but the male has important things to attend to at once. The minute, glass-clear eggs are considerably heavier than water and sink at once to the ground. Now the posture of the bodies in spawning is such that the sinking eggs are bound to drift past the downward directed head of the male and thus catch his attention. He gently releases the female, glides downwards in pursuit of the eggs and gathers them up, one after the other, in his mouth. Turning upwards again, he blows the eggs into the nest. They now miraculously float instead of sinking. This sudden and amazing change of density is caused by a coating of buoyant spittle in which the male has enveloped every egg while carrying it in his mouth. He has to hurry in this work, for not only would he soon be unable to find the tiny, transparent globules in the mud, but, if he should delay a second longer, the female would wake from her trance and, also swimming after the eggs, would likewise proceed to engulf them. From these actions, it would appear, at first sight, that the female has the same intentions as her mate. But if we wait to see her packing the eggs in the nest, we will wait in vain, for these eggs will disappear, irrevocably swallowed. So the male knows very well why he is hurrying, and he knows too, why he no longer allows the female near the nest when, after ten to twenty matings, all her eggs have been safely stored between the air bubbles.
The family life of the beautiful and courageous fishes of the cichlid group is much more highly developed than that of the fighting-fish. Here both male and female care for their young, which follow their parents as chickens the hen. For the first time in the ascending ranks of the scale of living creatures, we see in these cichlids a type of behaviour which human beings consider highly moral: male and female remain in close connubial partnership even after reproduction is completed. And not only do they remain so, as long as the care of the brood necessitates it, but—and this is what counts—still longer. It is usually described as “marriage” when both partners together fend for the brood, though, for this purpose, no really personal ties need exist between male and female; but in cichlids they do exist.
In order to ascertain objectively whether an animal recognizes its mate personally, the latter must be substituted, in experiment, by another of the same sex and in exactly the same phase of the reproductive cycle. If, for instance, in a pair of birds just beginning to nest, we replace the female by one that is already in the psycho-physiological phase of feeding its young, its instinctive behaviour will naturally fail to harmonize with that of the male. If the male then reacts inimically, it is impossible to say whether he really notices that the substituted female is not his wife or whether it merely annoys him that she behaves “wrongly”. I was greatly interested to find out how cichlids, the only fish that live in a “life-time marriage”, behave in this respect. The first thing necessary for the elucidation of this question was the possession of two pairs in exactly the same stages of their reproductive cycles. I was lucky enough, in the year 1941, to have two pairs of the magnificent, South-American cichlid Herichthys cyanoguttatus, which fulfilled this condition. The Latin name which, translated into English, means “Blue-spotted Hero-Fish”, is apposite: on a velvet-black background, deep turquoise-blue iridescent spots form an intricate mosaic, and a breeding pair of these fishes displays, even to the largest adversary, a heroism which justifies the second part of their name. When I first got them, my five young fishes of this species were neither bluespotted nor heroic. After some weeks of concentrated feeding in a large sunny aquarium they grew and flourished and, one day, one of the two biggest fishes showed his nuptial colours. He took possession of the left-hand lower front corner of the container, hollowed out a deep nesting cavity, and began to prepare a large smooth stone for spawning by carefully freeing it from algae and other deposits. The other four fish stood, huddled in an anxious group in the right upper rear corner. But by the next morning one of them, a smaller one, had also put on its gala dress; the velvet-black breast, devoid of blue spots, proved it to be a female. The male proceeded straightway to fetch his lady home, by a ceremony very similar to that described in the fighting-fish.
The pair now stood over the nesting place and defended its area valorously. This was no laughing matter for the three remaining fish, who were allowed no rest, being chased to and fro all the time, and it says much for the name-giving heroism of the species that, after some days, the second largest male plucked up enough courage to make conquest of the opposite corner. The two males now sat facing ea
ch other like two hostile knights in their castles. The border lay nearer the castle of the second one, a fact which will be appreciated after what I have said about territorial fighting: the fighting potential of the single male was smaller than the combined forces of the pair, and his territory was correspondingly smaller. The solitary male, which we will simply call number two, sallied forth again and again from his castle with the intention of abducting his neighbour’s wife. His attempts, however, were fruitless and brought him nothing but discomfiture. Every time he tried to pay court to her by displaying his magnificent broadside, she repaid his efforts by a ramming thrust in his unprotected flank. This situation remained unaltered for several days; then a second female donned her bridal dress and a happy end seemed imminent. But nothing of the kind occurred. On the contrary, the newly matured female paid as little attention to male number two as he to her and each ignored the other completely. Female number two tried again and again to approach male number one. Every time he swam towards his home, she followed, in the attitude of a female being led to the nest. She “considered” herself as being enticed nestwards whenever male number one, after a sally, swam back in that direction. His wife seemed to grasp the situation thoroughly, judging by the ferocity with which she attacked the intruder every time she approached; in this her husband only mildly participated. Male and female number two just did not exist for each other and each of them had eyes only for the opposite sex in the happily married pair which showed so little interest in them.
King Solomon's Ring Page 4
