Not all primate species are violently dictatorial in their social organization. There is nearly always a tyrant, but he is sometimes a benign and rather tolerant tyrant, as in the case of the mighty gorilla. He shares the females amongst the lesser males, is generous at feeding times, and only asserts himself when something crops up that cannot be shared, or when there are signs of a revolt, or unruly fighting amongst the weaker members.
This basic system obviously had to be changed when the naked ape became a co-operative hunter with a fixed home base. Just as with sexual behaviour, the typical primate system had to be modified to match his adopted carnivore role. The group had to become territorial. It had to defend the region of its fixed base. Because of the co-operative nature of the hunting, this had to be done on a group basis, rather than individually. Within the group the tyrannical hierarchy system of the usual primate colony had to be modified considerably to ensure full co-operation from the weaker members when out hunting. But it could not be abolished altogether. There had to be a mild hierarchy, with stronger members and a top leader, if firm decisions were going to be taken, even if this leader was obliged to take the feelings of his inferiors more into account than his hairy, forest-dwelling equivalent would have to do.
In addition to group defence of territory and hierarchy organization, the prolonged dependency of the young, forcing us to adopt pair-bonded family units, demanded yet another form of self-assertion. Each male, as the head of a family, became involved in defending his own individual home base inside the general colony base. So for us there are three fundamental forms of aggression, instead of the usual one or two. As we know to our cost, they are all still very much in evidence today, despite the complexities of our societies.
How does the aggression work? What are the patterns of behaviour involved? How do we intimidate one another? We must look again at the other animals. When a mammal becomes aggressively aroused a number of basic physiological changes occur within its body. The whole machine has to gear itself up for action, by means of the autonomic nervous system. This system consists of two opposing and counter-balancing sub-systems – the sympathetic and the parasympathetic. The former is the one that is concerned with preparing the body for violent activity. The latter has the task of preserving and restoring bodily reserves. The former says, ‘You are stripped for action, get moving’; the latter says, ‘Take it easy, relax and conserve your strength.’ Under normal circumstances the body listens to both these voices and maintains a happy balance between them, but when strong aggression is aroused it listens only to the sympathetic system. When this is activated, adrenalin pours into the blood and the whole circulatory system is profoundly affected. The heart beats faster and blood is transferred from the skin and viscera to the muscles and brain. There is an increase in blood pressure. The rate of production of red blood corpuscles is rapidly stepped up. There is a reduction of the time taken for blood to coagulate. In addition there is a cessation in the processes of digesting and storing food. Salivation is restrained. Movements of the stomach, the secretion of gastric juices, and the peristaltic movements of the intestines are all inhibited. Also, the rectum and bladder do not empty as easily as under normal conditions. Stored carbohydrate is rushed out of the liver and floods the blood with sugar. There is a massive increase in respiratory activity. Breathing becomes quicker and deeper. The temperature-regulating mechanisms are activated. The hair stands on end and there is profuse sweating.
All these changes assist in preparing the animal for battle. As if by magic, they instantly banish fatigue and make large amounts of energy available for the anticipated physical struggle for survival. The blood is pumped vigorously to the sites where it is most needed – to the brain, for quick thinking, and to the muscles, for violent action. The rise in blood sugars increases muscular efficiency. The speeding up of coagulation processes means that any blood spilled as a result of injury will clot more quickly and reduce wastage. The stepped-up release of red blood cells from the spleen, in combination with the increased speed of blood circulation, aids the respiratory system to boost the intake of oxygen and the removal of carbon dioxide. The full hair erection exposes the skin to the air and helps to cool the body, as does the outpouring of sweat from the sweat glands. The dangers of over-heating from excessive activity are therefore reduced.
With all the vital systems activated, the animal is ready to launch into the attack, but there is a snag. Out-and-out fighting may lead to a valuable victory, but it may also involve serious damage to the victor. The enemy invariably provokes fear as well as aggression. The aggression drives the animal on, the fear holds it back. An intense state of inner conflict arises. Typically, the animal that is aroused to fight does not go straight into an all-out attack. It begins by threatening to attack. Its inner conflict suspends it, tensed for combat, but not yet ready to begin it. If, in this state, it presents a sufficiently intimidating spectacle for its opponent, and the latter slinks away, then obviously this is preferable. The victory can be won without the shedding of blood. The species is able to settle its disputes without undue damage to its members and obviously benefits tremendously in the process.
Throughout the higher forms of animal life there has been a strong trend in this direction – the direction of ritualized combat. Threat and counter-threat has largely replaced actual physical combat. Full-blooded fighting does, of course, still take place from time to time, but only as a last resort, when aggressive signalling and counter-signalling have failed to settle a dispute. The strength of the outward signs of the physiological changes I have described indicates to the enemy just how violently the aggressive animal is preparing itself for action.
This works extremely well behaviourally, but physiologically it creates something of a problem. The machinery of the body has been geared up for a massive output of work. But the anticipated exertions do not materialize. How does the autonomic nervous system deal with this situation? It has mustered all its troops at the front line, ready for action, but their very presence has won the war. What happens now?
If physical combat followed on naturally from the massive activation of the sympathetic nervous system, all the body preparations it had made would be fully utilized. The energy would be burned up and eventually the parasympathetic system would reassert itself and gradually restore a state of physiological calm. But in the tense state of conflict between aggression and fear, everything is suspended. The result is that the parasympathetic system fights back wildly and the autonomic pendulum swings frantically back and forth. As the tense moments of threat and counter-threat tick by, we see flashes of parasympathetic activity interspersed with the sympathetic symptoms. Dryness in the mouth may give way to excessive salivation. Tightening of the bowels may collapse and sudden defecation may occur. The urine, held back so strongly in the bladder, may be released in a flood. The removal of blood from the skin may be massively reversed, extreme pallor being replaced by intense flushing and reddening. The deep and rapid respiration may be dramatically interrupted, leading to gasps and sighs. These are desperate attempts on the part of the parasympathetic system to counteract the apparent extravagance of the sympathetic. Under normal circumstances it would be out of the question for intense reactions in one direction to occur simultaneously with intense reactions in the other, but under the extreme conditions of aggressive threat, everything gets momentarily out of phase. (This explains why, in extreme cases of shock, fainting or swooning can be observed. In such instances the blood that has been rushed to the brain is withdrawn again so violently that it leads to sudden unconsciousness.)
As far as the threat-signalling system is concerned, this physiological turbulence is a gift. It provides an even richer source of signals. During the course of evolution these mood-signs have been built on and elaborated in a number of ways. Defecation and urination have become important territorial scent-marking devices for many species of mammals. The most commonly seen example of this is the way domestic dogs cock their
legs against marker-posts in their territories, and the way this activity is increased during threatening encounters between rival dogs. (The streets of our cities are excessively stimulating for this activity because they constitute overlapping territories for so many rivals, and each dog is forced to super-scent these areas in an attempt to compete.) Some species have evolved super-dunging techniques. The hippopotamus has acquired a specially flattened tail that is waggled rapidly back and forth during the act of defecating. The effect is that of shooting dung through a fan, with the result that the faeces are spread out over a wide area. Many species have developed special anal glands that add strong personal scents to the dung.
The circulatory disturbances producing extreme pallor or intense red flushes have become improved as signals by the development of bare patches of skin on the faces of many species and the rumps of others. The gasping and hissing of the respiratory disturbances have been elaborated into grunts and roars and the many other aggressive vocalizations. It has been suggested that this accounts for the origin of the whole communication system of vocal signals. Another basic trend developing out of respiratory turbulence is the evolution of inflation displays. Many species puff themselves up in threat and may inflate specialized air-sacs and pouches. (This is particularly common amongst birds, which already possess a number of air-sacs as a basic part of their respiratory systems.)
Aggressive hair-erection has led to the growth of specialized regions such as crests, capes, manes and fringes. These and other localized hair patches have become highly conspicuous. The hairs have become elongated or stiffened. Their pigmentation has often been drastically modified to produce areas of strong contrast with the surrounding fur. When aggressively aroused, with the hairs standing on end, the animal suddenly appears larger and more frightening, and the display patches become bigger and brighter.
Aggressive sweating has become another source of scent-signals. In many cases there have, once again, been specialized evolutionary trends exploiting this possibility. Certain of the sweat glands have become enormously enlarged as complex scent-glands. These can be found on the faces, feet, tails and various parts of the body of many species.
All these improvements have enriched the communication systems of animals and rendered their mood language more subtle and informative. They make the threatening behaviour of the aroused animal more ‘readable’ in more precise terms.
But this is only half the story. We have been considering only the autonomic signals. In addition to all these there is another whole range of signals available, which stem from the tensed-up muscular movements and postures of the threatening animal. All that the autonomic system did was to gear the body up ready for muscular action. But what did the muscles do about it? They were stiffened for the onslaught, but no onslaught came. The outcome of this situation is a series of aggressive intention movements, ambivalent actions, and conflict postures. The impulses to attack and to flee pull the body this way and that. It lunges forward, pulls back, twists sideways, crouches down, leaps up, leans in, tilts away. As soon as the urge to attack gets the upper hand, the impulse to flee immediately countermands the order. Every move to withdraw is checked by a move to attack. During the course of evolution this general agitation has become modified into specialized postures of threat and intimidation. The intention movements have become stylized, the ambivalent jerkings have become formalized into rhythmic twistings and shakings. A whole new repertoire of aggressive signals has been developed and perfected.
As a result of this we can witness, in many animal species, elaborate threat rituals and combat ‘dances’. The contestants circle one another in a characteristically stilted fashion, their bodies tense and stiff. They may bow, nod, shake, shiver, swing rhythmically from side to side, or make repeated short, stylized runs. They paw the ground, arch their backs, or lower their heads. All these intention movements act as vital communication signals and combine effectively with the autonomic signals to provide a precise picture of the intensity of the aggression that has been aroused, and an exact indication of the balance between the urge to attack and the urge to flee.
But there is yet more to come. There is another important source of special signals, arising from a category of behaviour that has been named displacement activity. One of the side-effects of an intense inner conflict is that an animal sometimes exhibits strange and seemingly irrelevant pieces of behaviour. It is as if the tensed-up creature, unable to perform either of the things it is desperate to do, finds an outlet for its pent-up energy in some other, totally unrelated activity. Its urge to flee blocks its urge to attack and vice versa, so it vents its feelings in some other way. Threatening rivals can be seen suddenly to perform curiously stilted and incomplete feeding movements, and then return instantly to their full threat postures. Or they may scratch or clean themselves in some way, interspersing these movements with the typical threat manœuvring. Some species perform displacement nest-building actions, picking up pieces of nest material that happen to lie near by and dropping them on to imaginary nests. Others indulge in ‘instant sleep’, momentarily tucking their heads into a snoozing position, yawning or stretching.
There has been a great deal of controversy about these displacement activities. It has been argued that there is no objective justification for referring to them as irrelevancies. If an animal feeds, it is hungry, and if it scratches it must itch. It is stressed that it is impossible to prove that a threatening animal is not hungry when it performs so-called displacement feeding actions, or that it is not itching when it scratches. But this is armchair criticism, and to anyone who has actually observed and studied aggressive encounters in a wide variety of species, it is patently absurd. The tension and drama of these moments is such that it is ridiculous to suggest that the contestants would break off, even momentarily, to feed for the sake of feeding, or scratch for the sake of scratching, or sleep for the sake of sleeping.
Despite the academic arguments about the causal mechanisms involved in the production of displacement activities, one thing is clear, namely that in functional terms they provide yet one more source for the evolution of valuable threat signals. Many animals have exaggerated these actions in such a way that they have become increasingly conspicuous and showy.
All these activities, then, the autonomic signals, the intention movements, the ambivalent postures and the displacement activities, become ritualized and together provide the animals with a comprehensive repertoire of threat signals. In most encounters they will be sufficient to resolve the dispute without the contestants coming to blows. But if this system fails, as it often does under conditions of extreme crowding, for example, then real fighting follows and the signals give way to the brutal mechanics of physical attack. Then, the teeth are used to bite, slash and stab, the head and horns to butt and spear, the body to ram, bump and push, the legs to claw, kick and swipe, the hands to grasp and squeeze, and sometimes the tail to thrash and whip. Even so, it is extremely rare for one contestant to kill the other. Species that have evolved special killing techniques for dealing with their prey seldom employ these when fighting their own kind. (Serious errors have sometimes been made in this connection, with false assumptions about the presumed relationship between prey-attacking behaviour and rival-attacking activities. The two are quite distinct in both motivation and performance.) As soon as the enemy has been sufficiently subdued, it ceases to be a threat and is ignored. There is no point in wasting additional energy on it, and it is allowed to slink away without further damage or persecution.
Before relating all these belligerent activities to our own species, there is one more aspect of animal aggression that must be examined. It concerns the behaviour of the loser. When his position has become untenable, the obvious thing for him to do is to remove himself as fast as he can. But this is not always possible. His escape route may be physically obstructed, or, if he is a member of a tightly knit social group, he may be obliged to stay within range of the victor. In either of these
cases, he must somehow signal to the stronger animal that he is no longer a threat and that he does not intend to continue the fight. If he leaves it until he is badly damaged or physically exhausted, this will become obvious enough, and the dominant animal will wander off and leave him in peace. But if he can signal his acceptance of defeat before his position has deteriorated to this unfortunate extreme, he will be able to avoid further serious punishment. This is achieved by the performance of certain characteristic submissive displays. These appease the attacker and rapidly reduce his aggression, speeding up the settlement of the dispute.
They operate in several ways. Basically, they either switch off the signals that have been arousing the aggression, or they switch on other, positively non-aggressive signals. The first category simply serve to calm the dominant animal down, the latter help by actively changing his mood into something else. The crudest form of submission is gross inactivity. Because aggression involves violent movement, a static pose automatically signals non-aggression. Frequently this is combined with crouching and cowering. Aggression involves expanding the body to its maximum size, and crouching reverses this and therefore acts as an appeasement. Facing away from the attacker also helps, being the opposite of the posture of frontal attack. Other threat-opposites are also used. If a particular species threatens by lowering its head, then raising the head can become a valuable appeasement gesture. If an attacker erects its hair, then compressing it will serve as a submission device. In certain rare cases a loser will admit defeat by offering a vulnerable area to the attacker. A chimpanzee, for example, will hold out its hand as a gesture of submission, rendering it extremely vulnerable for serious biting. Because an aggressive chimpanzee would never do such a thing, this begging gesture serves to appease the dominant individual.
The Naked Ape Page 15