Human beings learn to utter sounds before they are able to speak, and learn to read words before they are able to write them. To the same extent human beings also learn to read a picture before they are able to draw. The fact that a person is capable of reading does not imply that he can write, but if he is capable of writing it can safely be assumed that he can read as well, since writing includes reading as a prior condition, but not the contrary. That is to say, writing is a skill of a higher level of order than reading and it is therefore natural that it always appears at a later stage than reading. From this it is clear that human beings must have known how to read something very like pictures before they were able to draw pictures! If this is indeed so, what pictures did the hunters read before there were pictures? The answer is written on the ground: they read marks that were a kind of 'natural drawing' outlined on the ground without intention or awareness on the part of those who 'drew' them; these were the footprints of animals and human beings. As we shall see, it is almost certain that hominids were already able to read footprints some four million years ago. It seems very reasonable to assume that for the early hunters, as for trackers of all times, footprints were graphic indications, substitutions or even representations of the creatures that produced them, and this is therefore probably the beginning of symbolization and of the capacity of reading graphic representations. If one of the essential attributes that characterize human consciousness is the capacity of thinking in marks related to hypothetical entities, then the reading of footprints is almost certainly the earliest expression of the ability of man to think referentially. On the other hand, some millions of years were needed before the hunters could generalize from the reading of these natural representations, to the 'writing' or drawing of footprints and handprints on the walls of caves and rock shelters (See Fig. 1). After this, only a short while was needed for them to generalize from the depiction of hands and feet by the contours of those limbs, to the depiction of the prints of entire animals and men by the contours of their bodies. If image making is indeed a generalization of footprints literacy, it has to be shown that the footprint has the overwhelming majority of the most important attributes possessed by drawings, even if on a less developed level than drawing. Another aspect of the same matter that must be shown is, that the reading of footprints requires skills and cognitive abilities similar to those needed for the reading and use of pictorial symbols. In other words, it has to be shown that footprints are the proto-symbols from which the symbols of figurative art may have developed.

Hunters invented prehistoric art, and the hunter's chief skill is not killing but tracking; this is the ability to decipher the enormous plurality of marks that make up his environment. Footprints are one of the most important kinds of marks that the hunters of all times must have been acquainted with, for as a rule it is easier to find footprints than to find the animals that leave these footprints. Very great expertise in deciphering marks is a necessary condition for the hunter's existence both in securing food for himself and his family and furthermore not to become himself food for another animal. Marks based on the senses of hearing or smell are only very effective at a short distance from their source, and they are therefore efficient mainly for creatures that are sufficiently strong to be able to attack their prey without danger to themselves, such as the large predators; or sufficiently swift to flee quickly enough when sudden danger is revealed. But for man, who has neither of these advantages, and particularly when he had as yet no weapons at all, his only advantage was perhaps the ability to decipher a special kind of marks even at a very great distance from the animal that left them: footprints. According to the type of footprints and their characteristics, the hunter could choose whether to ignore them, to rapidly reduce the distance between himself and the animal in order to make a kill, or to distance himself from it. The main difference between footprints and the other marks or indications such as all kinds of secretions, smells, sounds, etc., is that all of these are real entities with positive existence, and in most cases are an actual part of the animal that has become detached from it. By contrast, footprints derive from the absence of soil in an amount and of a shape that fits the foot of a particular animal. The footprint then, is not material but is the pattern of the foot that left it. A pattern is a kind of abstract indication of the animal, but not of a kind from which it is possible to generalize with the aid of one of the senses to the identification of the animal that left it, but only by means of very complex cognitive activity of the kind required for symbolic thinking. Munn describes an instructive example of a special integration of footprints literacy, drawing, and verbal thinking among present-day hunter-gatherers, the Walbiri in Central Australia: "Among the most prominent of the graphs that Walbiri draw in the sand are track prints of animals and birds and circle or circle-line notations referring to places and journeys... Footprints are impressed in the sand by holding the hand in various special positions; their production is a casual play activity in which men, women, and children may indulge." (Munn, 1973. 119). If footprints literacy is likely to be such a basic component in the thinking of contemporary hunter-gatherers, it may be supposed that among prehistoric hunter-gatherers, footprints literacy was almost certainly an even more basic component in their thinking, for they were chiefly visual thinkers, and only to a marginal degree verbal thinkers as well.

The identification of an animal by means of its footprints entails cognitive abilities that have a great deal in common with the capacities needed by the prehistoric draughtsman, and the capacities needed by the scientist today. In the three cases, footprints literacy, prehistoric image making and modern science, the same attributes are required, but at different levels, and these attributes can be identified for the first time in footprints literacy: connectivity, differentiation, grouping, classification, abstraction, generalization, thinking in visual universals or visual class-names which in this case are visual schemes of an object derived from its contours, pattern recognition: the identification of symmetries and transformations of those symmetries, complementarity of figure and ground, induction and deduction, construction of hypotheses and their empirical testing, thinking in terms of spatial order, in time and causality, the ability to reconstruct in the imagination and thought, hypothetical processes connected with the behavior of the animal, et cetera. All this and more is required for a hunter to deduce which animal left the footprints. It is true that a similar cognitive activity is also present when trying to deduce what animal left particular droppings. But this activity is at a far lower level, for in this case a part of the animal itself is given, and therefore there are in this case far fewer possibilities of making a mistake in obtaining a correct solution. The awareness of the cognitive mechanisms involved in footprints literacy makes obligatory a theory of a level of conceptualization and abstraction that is quite high even today, when our thinking is much more conceptual than visual. It is therefore obvious that the cognitive mechanisms involved in footprints literacy among hunters of all times, are mostly unconscious. The same is true, not only concerning the prehistoric hunters who initiated image making and whose thinking was undoubtedly much more in visual (and other) terms than in verbal terms, but also with regard to image makers of all times. Now it is easier to show that the emergence of image making probably followed from generalization and elaboration of the principles of the visual thinking that had served hunters for millions of years before in footprints literacy and tool making.