First in Line: Tracing Our Ape Ancestry

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First in Line

Yale University Press

Chapter One

Long before Charles Darwin and his intellectual heirs began to seriously consider the biological evolution of modern human beings from some "nonhuman" species, Western thinkers formulated a very different way of understanding the natural world around them. For the greater part of the last two millennia, nature was viewed as an unchanging arrangement of living things, organized in a linear sequence with the simplest, most primitive forms at the bottom and the most complex organisms near the top. This "Chain of Being," also called the Scala Naturae, reflected the boundless wisdom of some ultimate creative force, and was considered perfect: "The Chain of Being, in so far as its continuity and completeness were armed on the customary grounds, was a perfect example of an absolutely rigid and static scheme of things." Perspectives on nature that developed at least up until the fifteenth century assumed the Chain of Being as a foundation, even if other detailed aspects of natural philosophy differed (Fig. 1.1).

The Chain of Being has manifold definitions and interpretations, philosophical, sociopolitical, religious, and otherwise (Lovejoy 1936, Kuntz andKuntz 1987), but in terms of the biological sciences it can be described as a device designed to impose simple order on the complex natural world. This chapter briefly examines the development of this idea, and more particularly focuses on the place occupied by Homo sapiens by providing an outline of the different types of organisms, sometimes hypothetical or mythological, believed to reside near humans on the Chain. While this review is certainly not exhaustive, it is included to demonstrate that prior to the emergence of evolutionary thought it was recognized that some animals were clearly more humanlike than others. As will become apparent in subsequent chapters, in order for later naturalists working within an evolutionary paradigm to begin contemplating what a human ancestor might have looked like, especially without a significant fossil record, knowledge of which living species were most similar to humans was crucial.

The Chain of Being in Antiquity

As is the case with so many modern Western ideas, our story begins in the minds of the classical Greeks. According to philosopher Arthur Lovejoy (1936), the idea of a universe that contained all possible things can be traced back to Plato. Lovejoy refers to this idea as the principle of plenitude. Basically, since there were no limits on the mind of the creator, all things had to exist, and were present in their pure form in the otherworldly universe of ideas, or essences. Further, each of these archetypes had a representation in the visible world, which humans could more readily comprehend. This meant that everything that could be created did, in fact, exist. Although the observable world was only a dark and blurry reflection of the perfect other-world, it still had to contain a manifestation of every single one of those ideas, or the system collapsed (that is, it was no longer perfect). Variation between individuals of any given type could be explained by the fact that what humans observed was only an imperfect copy of the archetype.

Not only did everything possible exist, but each type was viewed as passing imperceptibly into its neighbor above and below on the Great Chain. This is Lovejoy's second principle, that of continuity. Plato's student Aristotle clearly accepted these first two principles: "Nature proceeds from the inanimate to the animals by such small steps that, because of the continuity, we fail to see to which side the boundary and the middle between them belongs." One important, and logical, outgrowth of these two principles was the idea that between any two known similar organisms, there could theoretically be some missing link. The idea of a missing link was maintained after the emergence of evolutionary thought, but in a modified form.

Aristotle also introduced Lovejoy's third and final principle, that of gradation. Despite the supposed continuity along the Great Chain it was possible to rank animate creatures as more or less perfect, and place them accordingly. Hence the Great Chain was value laden to the extent that it placed everything nearer to or more distant from the creator. Of all secular beings humans were, naturally, considered the most perfect on Earth.

If the immutable Great Chain provided the theoretical context in which to view nature, what were the details of the region where humans resided? In accordance with the concepts of plenitude, continuity, and gradation, it was assumed that organisms existed which very closely approached the human condition. Above were found supernatural entities (angels and gods, for example), which were beyond the purview of human analysis, and below were various creatures that did not quite achieve the level of humanity. The latter group fell into two broad categories. The first were the mythological, yet theoretically possible, wild races discussed by many authors in antiquity. The other category included the various nonhuman primates that were encountered firsthand or occasionally formed a part of travelers' tales. All of these creatures, despite their similarities to humans, were different in some fundamental way. Exactly how they were perceived as different hinged on the prevailing definition of "human," a definition that continues to be modified even today (Cartmill 1990, Stanford 2001).

Throughout antiquity there were stories of wild races that resided just below true humans on the Great Chain. Various classical Greek writers provided accounts of these creatures; for example Herodotus gave a brief account of fantastic creatures living in Libya: "Here too [western Libya] are the dog-faced creatures, and the creatures without heads, whom the Libyans declare to have their eyes in their breasts; and also the wild men, and wild women, and many other far less fabulous beasts." Alexander the Great's travels to the East during the fourth century B.C. exposed him to Indian lore concerning fabulous creatures such as the ichthyophagi of northern India, who lived at the bottom of the sea and ate nothing but fish (Wittkower 1942).

Centuries later, Pliny the Elder offered descriptions of numerous monstrous races in his Natural History, written around 77 A.D. Some of these were drawn from older "firsthand" accounts: "India and regions of Ethiopia are especially full of wonders.... On many mountains there are men with dogs' heads who are covered with wild beasts' skins; they bark instead of speaking ... and further to the east of these are some people without necks and with eyes in their shoulders." Another such race was a tribe of people living along the Niger River called the Blemmyae, who "are reported as being without heads; their mouth and eyes are attached to their chest."

It is not certain to what degree people actually believed in the existence of these creatures, and in fact some did deny their existence. In some cases, they may have been exaggerated descriptions of nonhuman primate species; Pliny's cynocephali may have referred to African baboons whose long snouts resemble those of dogs. In other cases these mythical wild races may have actually represented human populations, or pathological individuals, again exaggerated by those documenting them. Alexander's ichthyophagi may have been based on an encounter with a group of fishing people who didn't cook but only dried their fish before consuming it. Regardless, what remains important is that each of these semihumans fulfilled one of the infinite theoretical spaces along the Chain of Being.

In addition to these fantastic creatures, there survive ancient descriptions of primates-certainly of monkeys, and less certainly of apes. As with the wild races, their anatomical similarities to humans were taken to indicate their relative proximity on the scale of nature. It is certain that ancient civilizations knew about monkeys living in their immediate areas. Ancient Egyptians considered the Hamadryas baboon to be sacred from pre-dynastic times onward. Upon dying, especially important people had their internal organs separately mummified within containers called canopic jars, one of which had the baboon carved into the lid. The mummified remains of baboons have also been recovered, indicating the special treatment they received in contrast to other animals. There is some evidence that ancient Egyptians knew of other monkey species, but these were not regarded with the same reverence as the Hamadryas baboon.

Although monkeys are not indigenous to the regions encompassing ancient Mesopotamia, Palestine, Asia Minor, and Syria, some artistic representations of them have been recovered. Monkeys were presumably brought into the region from Egypt, or perhaps could have come from the East. In India, langurs have been revered throughout Hindu history, and the monkey god Hanuman is often shown with Rama. It is probable that classical explorers and scholars also knew of Asian macaques.

Ancient texts reveal that classical Greek and Roman authors also noted endemic monkeys' similarity to humans and to images of monkeys displayed in a variety of artistic contexts (such as vases and paintings). While their use in religious settings has not been confirmed, the ancient Greeks did provide the first natural history-type reports of monkeys. In the Voyage of Hanno (fifth century B.C.), along the west coast of Africa Hanno's group encountered "another island, full of savage people, the greater part of whom were women, whose bodies were hairy, and whom our interpreters called Gorillae." Three of these were killed and their skins were taken back to Carthage. That Hanno actually encountered the animal we call a gorilla today is not very plausible; it is more likely that he stumbled upon a troop of baboons.

As head of the classical Greek school called the Lyceum in Athens, Aristotle, along with others, carried out systematic collection and comparison of a variety of organisms, and erected a rudimentary taxonomic system. He divided primates into three types in History of Animals: "Some animals dualize in their nature with man and the quadrupeds, e.g., the ape, the monkey and the baboon. The monkey is an ape with a tail. The baboon is identical in form with the ape, except that it is bigger and stronger and its face is more like a dog's; also it is of a fiercer disposition and its teeth are more doglike and stronger. Apes are hairy on the back, in virtue of their being quadrupeds, and hairy on their fronts, in virtue of being manlike.... Its face shows many resemblances to that of man: it has similar nostrils and ears, and teeth, both front and molars, like man's.... Besides this, the ape has hands, fingers and nails like a man, except that all these parts tend to be more beastlike.... In all animals of this sort the internal parts, when dissected, resemble those of man."

Somewhat later, Pliny, in addition to describing the many wild races, also made passing reference to nonhuman primates: "There are also Satyrs in the mountains of eastern India, in the region of the Catarcludi. These are very fast-moving animals, sometimes running on all fours, sometimes upright like humans."

Also, and here it seems obvious that he is not speaking from firsthand knowledge, Pliny wrote: "The types of apes that are closest to humans in shape are distinguished from one another by their tails. Apes are extraordinarily cunning characters. People say they smear themselves with bird droppings and in imitation of hunters put on nooses, set to catch them, as if they are shoes. Mucianus says that apes with tails have played draughts and can distinguish real nuts from imitations made from wax. They are sad when the moon wanes and worship the new moon with great glee." This overtly anthropomorphic passage underscores the point that in ancient times scholars had already identified several kinds of animals that were more or less humanlike in their appearance and perhaps behavior, even if a rigorous taxonomic classification was wanting.

Galen was a Greek physician who wrote a number of anatomical treatises that remained unsurpassed until the Renaissance. While living in Rome, as physician to the emperor, he wrote On Anatomical Procedures, which described detailed procedures for dissection. The unavailability of human cadavers led Galen to dissect other primates as proxies in teaching anatomy to his students. Throughout the text Galen justifies the use of nonhuman primates by explaining that since the skeletons of apes and humans are so similar, it follows that the soft tissue structures that use the skeleton as scaffolding must also be very similar: "As poles to tents and walls to houses, so are bones to living creatures, for other features naturally take form from them and change with them.... Now of all living things the ape is likest man in viscera, muscles, arteries, veins, and nerves, as in the form of the bones."

Galen may have used rhesus macaques for many of his dissections, but it is probable that he, like Aristotle, was speaking of the comparatively rare Barbary macaque when he mentioned apes, and distinguished these from the cynocephali or baboons: "Choose those apes likest man, with short jaws and small canines. You will find other parts also resembling man's, for they can walk and run on two feet. Those, on the other hand, like the dog-faced baboons, with long snouts and large canines, far from walking or running on their hind-legs, can hardly stand upright."

The Great Chain of Being in the Middle Ages

Throughout the Middle Ages, accounts of both actual primates and of mythical races persisted, often simply transcribed, and accepted uncritically, from the works of classical authors such as Pliny. Little more empirical evidence was generated concerning the natural history of nonhuman primates, and no convincing evidence supporting the discovery of the anthropoid apes appeared until the fifteenth century.

Despite the lack of new biological knowledge concerning these animals, there was no shortage of images of monkeys in the literature and art of the time. In addition, early Christian authors accepted the Chain of Being as an organizing principle of nature and noted, often with disdain, the similarity of monkeys, and other nonhuman forms, to humans. In City of God St. Augustine stated:

Now among those things which exist in any mode of being, and are distinct from God who made them, living things are ranked above inanimate objects; those which have the power of reproduction, or even the urge towards it, are superior to those who lack that impulse. Among living things, the sentient, the intelligent rank above the insensitive, and animals above trees. Among the sentient, the intelligent take precedence over the unthinking-men over cattle. Among the intelligent, immortal beings are higher than mortals, angels being higher than men. This is the scale to the order of nature....

If these races [Pliny's monstrous races] are included in the definition of "human," that is if they are rational and mortal animals, it must be admitted that they trace their lineage from that same one man the first father of all mankind. The definition is important; for if we did not know that monkeys, long-tailed apes and chimpanzees are not men but animals, those natural historians who plume themselves on their collection of curiosities might pass them o on us as races of men.

While the anatomical similarity to humans remained a matter for discussion, what was of greater interest to St. Augustine, and many subsequent authors, was the psychology of these creatures, and particularly their presumed lack of reason. Additionally, it was suggested that only humans had immortal souls, therefore nonhuman primates were placed in an inferior category.

Later in the Middle Ages, the perception of monkeys and apes changed once again, perhaps as they became more commonly encountered due to the increasing introduction to Europe of exotic objects from the East and the Mediterranean littoral. Two of the more widely known compendia from the late middle ages, those of Gesner (1551) and Aldrovandi (1637), have sections on the Simia, and mainly borrowed from classical accounts and sometimes questionable contemporary accounts.

(Continues...)

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Excerpted from First in Line by Tom Gundling Copyright © 2005 by Yale University. Excerpted by permission.
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