Up to this point I have been concentrating on the social aspects of comfort behaviour in our species. As we have seen there have been great developments in that direction, but this has not excluded or replaced the simpler kinds of self-cleaning and selfcomfort. Like other primates we still scratch ourselves, rub our eyes, pick our sores, and lick our wounds. We also share with them a strong tendency to sun-bathe. In addition we have added a number of specialised cultural patterns, the most common and widespread of which is washing with water. This is rare in other primates, although certain species bathe occasionally, but for us it now plays the major role in body cleaning in most communities.
Despite its obvious advantages, frequent cleansing with water nevertheless puts a severe strain on the production of antiseptic and protective oils and salts by the skin glands, and to some extent it is bound to make the body surface more susceptible to diseases. It survives this disadvantage only because, at the same time that it eliminates the natural oils and salts, it removes the dirt that is the source of these diseases.
In addition to problems of keeping clean, the general category of comfort behaviour also includes those patterns of activity concerned with the task of maintaining a suitable body temperature. Like all mammals and birds, we have evolved a constant, high body temperature, giving us greatly increased physiological efficiency. If we are healthy, our deep body temperature varies no more than 30 Fahrenheit, regardless of the outside temperature. This internal temperature fluctuates with a daily rhythm, the highest level occurring in the late afternoon and the lowest at around 4 a.m. If the external environment becomes too hot or too cold we quickly experience acute discomfort. The unpleasant sensations we receive act as an early warning system, alerting us to the urgent need to take action to prevent the internal body organs from becoming disastrously chilled or overheated. In addition to encouraging intelligent, voluntary responses, the body also takes certain automatic steps to stabilise its heat level. If the environment becomes too hot, vasodilation occurs. This gives a hotter body surface and encourages heat loss from the skin. Profuse sweating also takes place. We each possess approximately two million sweat glands. Under conditions of intense heat these are capable of secreting a maximum of one litre of sweat per hour. The evaporation of this liquid from the body surface provides another valuable form of heat loss. During the process of acclimatisation to a generally hotter environment, we undergo a marked increase in sweating efficiency. This is vitally important because, even in the hottest climates, our internal body temperature can only stand an upward shift of 0-40 Fahrenheit, regardless of our racial origin.
If the environment becomes too cold, we respond with vasoconstriction and with shivering. The vasoconstriction helps to conserve the body heat and the shivering can provide up to three times the resting heat production. If the skin is exposed to the intense cold for any length of time, there is a danger that the prolonged vasoconstriction will lead to frostbite. In the hand region there is an important, built-in, anti-frostbite system. The hands at first respond to intense cold by drastic vasoconstriction; then, after about five minutes, this is reversed and there is strong vasodilation, the hands becoming hot and flushed. (Anyone who has been snowballing in winter will have experienced this.) The constriction and dilation of the hand region then continues to alternate, the constriction phases curtailing heat loss and the dilation phases preventing frostbite. Individuals living permanently in a cold climate undergo various forms of bodily acclimitisation, including a slightly increased basal metabolic rate.
As our species has spread over the globe, important cultural additions have been made to these biological temperature control mechanisms. The development of fire, clothing, and insulated dwelling-houses have combated heat loss, and ventilation and refrigeration have been used against heat gain. Impressive and dramatic as these advances have been, they have in no way altered our internal body temperature. They have merely served to control the external temperature, so that we can continue to enjoy our primitive primate temperature level in a more diverse ran e: of external conditions. Despite recent claims, suspended animation experiments involving special freezing techniques are still confined to the realms of science fiction.
Before leaving the subject of temperature responses, there is one particular aspect of sweating that should be mentioned. Detailed studies of sweating responses in our species have revealed that they are not as simple as they may first appear. Most areas of the body surface begin to perspire freely under conditions of increased heat, and this is undoubtedly the original, basic response of the sweat-gland system. But certain regions have become reactive to other types of stimulation and sweating can occur there regardless of the external temperature. The eating of highly spiced foods, for example, produces its own special pattern of facial sweating. Emotional stress quickly leads to sweating on the palms of the hands, the soles of the feet, the armpits and sometimes also the forehead, but not on other parts of the body. There is a further distinction in the areas of emotional sweating, the palms and the soles differing from the armpits and the forehead. The first two regions respond well only to emotional situations, whereas the last two react to both emotional and to temperature stimuli. It is dear from this that the hands and feet have ‘borrowed’ sweating from the temperature control system and are now using it in a new functional context. The moistening of the palms and soles during stress appears to have become a special feature of the ‘ready for anything’ response that the body gives when danger threatens. Spitting on the hands before wielding an axe is, in a sense, the non-physiological equivalent of this process.
So sensitive is the palmary sweating response that whole communities or nations may show sudden increases in this reaction if their group security is threatened in some way. During a recent political crisis, when there was a temporary increase in the likelihood of nuclear war, all experiments into palmary sweating at a research institute had to be abandoned because the base level of the response had become so abnormal that the tests would have been meaningless. Having our palms read by a fortune-teller may not tell us much about the future, but having them read by a physiologist can certainly tell us something about our fears for the future.
UP to this point we have been considering the naked ape’s behaviour towards himself and towards members of his own species—his intra-specific behaviour. It now remains to examine his activities in relation to other animals—his inter-specific behaviour.
All the higher forms of animal life are aware of at least some of the other species with which they share their environment. They regard them in one of five ways: as prey, symbionts, competitors, parasites, or predators. In the case of our own species, these five categories may be lumped together as the ‘economic’ approach to animals, to which may be added the scientific, aesthetic and symbolic approaches. This wide range of interests has given us an inter-specific involvement unique in the animal world. In order to unravel it and understand it objectively we must tackle it step by step, attitude by attitude.
Because of his exploratory and opportunist nature, the naked ape’s list of prey species is immense. At some place, at some time, he has killed and eaten almost any animal you care to mention. From a study of prehistoric remains we know that about half a million years ago, at one site alone, he was hunting and eating species of bison, horse, rhino, deer, bear, sheep, mammoth, camel, ostrich, antelope, buffalo, boar and hyaena. It would be pointless to compile a ‘species menu’ for more recent times but one feature of our predatory behaviour does deserve mention, namely our tendency to domesticate certain selected prey species. For, although we are likely to eat almost anything palatable on occasion, we have nevertheless limited the bulk of our feeding to a few major animal forms.
Domestication of livestock, involving the organised control and selective breeding of prey, is known to have been practised for at least, ten thousand years and, in certain cases, probably much longer. Goats, sheep and reindeer appear to have been the earliest prey species dealt with in this way. Then, with the development of settled agricultural communities, pigs and cattle, including Asiatic buffalo and yak, were added to the list. We have evidence that, in the case of cattle, several distinct breeds had already been developed four thousand years ago. Whereas the goats, sheep and reindeer were transformed directly from hunted prey to herded prey, it is thought that the pigs and cattle began their close association with our species as crop-robbers. As soon as cultivated crops were available, they moved in to take advantage of this rich new food supply, only to be taken over by the early farmers and brought under domestic control themselves.
The only small mammalian prey species to undergo prolonged domestication was the rabbit, but this was apparently a much later development. Amongst the birds, important prey species domesticated thousands of years ago were the chicken, the goose and the duck, with later minor additions of the pheasant, guinea fowl, quail and turkey. The only prey fish with a long history of domestication are the Roman eel, the carp and the goldfish. The latter, however, soon became ornamental rather than gastronomic. The domestication of these fish is limited to the last two thousand years and has played only a small role in the general story of our organised predation.
The second category in our list of inter-specific relationships is that of the symbiont. Symbiosis is defined as the association of two different species to their mutual benefit. Many examples of this are known from the animal world, the most famous being the partnership between the tick birds and certain large ungulates such as the rhinoceros, giraffe and buffalo. The birds eat the skin parasites of the ungulates, helping to keep the bigger animals healthy and dean, while the latter provide the birds with a valuable source of food.
Where we ourselves are one of the members of a symbiotic pair, the mutual benefit tends to become biased rather heavily in our favour, but it is nevertheless a separate category, distinct from the more severe prey-predator relationship, since it does not involve the death of the other species concerned. They are exploited, but in exchange for the exploitation we feed and care for them. It is a biased symbiosis because we are in control of the situation and our animal partners usually have little or no choice in the matter.
The most ancient symbiont in our history is undoubtedly the dog. We cannot be certain exactly when our ancestors first began to domesticate this valuable animal, but it appears to be at least ten thousand years ago. The story is a fascinating one. The wild, wolf-like ancestors of the domestic dog must have been serious competitors with our hunting forebears. Both were co-operative pack-hunters of large prey and, at first, little love can have been lost between them. But the wild dogs possessed certain special refinements that our own hunters lacked. They were particularly adept at herding and driving prey during hunting manoeuvres and could carry this out at high speed. They also had more delicate senses of smell and hearing. If these attributes could be exploited in exchange for a share in the kill, then the bargain was a good one. Somehow we do not know exactly how this came about and an inter-specific bond was forged. It is probable that it began as a result of young puppies being brought in to the tribal home base to be fattened as food. The value of these creatures as alert nocturnal watch-dogs would have scored a mark in their favour at an early stage. Those that were allowed to live in a now tamed condition and permitted to accompany the males on their hunting trips would soon show their paces in assisting to track down the prey. Having been hand-reared, the dogs would consider themselves to be members of the naked-ape pack and would cooperate instinctively with their adopted leaders. Selective breeding over a number of generations would soon weed out the trouble-makers and a new, improved stock of increasingly restrained and controllable domestic hunting dogs would arise.
It has been suggested that it was this progression in the dog relationship that made possible the earliest forms of ungulate prey domestication. The goats, sheep and reindeer were under some degree of control before the advent of the true agricultural phase, and the improved dog is envisaged as the vital agent that made this feasible by assisting in the large-scale and long-term herding of these animals. Studies of the driving behaviour of present day sheepdogs and of wild wolves reveal many similarities in technique and provide strong support for this view.
During more recent times, intensified selective breeding has produced a whole range of symbiotic dog specialisations. The primitive all-purpose hunting dog assisted in all stages of the operation, but his later descendants were perfected for one or other of the different components of the overall behaviour sequence. Individual dogs with unusually well developed abilities in a particular direction were inbred to intensify their special advantages. As we have already seen, those with good qualities in manoeuvring became herding dogs, their contribution being confined largely to the rounding up of domesticated prey (sheepdogs). Others, with a superior sense of smell were inbred as scent-trackers (hounds). Others, with an athletic turn of speed, became coursing dogs and were employed to chase after prey by sight (greyhounds).
Another group were bred as prey-spotters, their tendency to ‘freeze’ when locating the prey being exploited and intensified (setters and pointers). Yet another line was improved as prey-finders and carriers (retrievers). Small breeds were developed as vermin-killers (terriers). The primitive watchdogs were genetically improved as guard-dogs (mastiffs).
In addition to these widespread forms of exploitation, other dog lines have been selectively bred for more unusual functions. The most extraordinary example is the hairless dog of the ancient New World Indians, a genetically naked breed with an abnormally high skin temperature that was used as a primitive form of hot water-bottle in their sleeping quarters.