Foraging in Tropical Rain Forests: The Case of the Penan of Sarawak, East Malaysia (Borneo)Author(s): J. Peter BrosiusSource: Human Ecology, Vol. 19, No. 2, Human Foragers in Tropical Rain Forests (Jun., 1991),pp. 123-150Published by: SpringerStable URL: http://www.jstor.org/stable/4603008 .Accessed: 15/09/2011 00:30

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Human Ecology, Vol. 19, No. 2, 1991

Foraging in Tropical Rain Forests: The Case of the Penan of Sarawak, East Malaysia (Borneo)

J. Peter Brosius'

Bailey et al. (1989) and Headland (1987) have recently proposed hypotheses stating that human foragers are unable to live in undisturbed tropical rain forests without some reliance on cultivated foods. The present discussion con- siders these hypotheses, as well as some of the evidence by which they have been tested. Four conceptual problems in the way these hypotheses have been formulated are identified: (1) assumptions about the relationship between key features of tropical forest ecosystems and human subsistence potential, (2) in- consistencies in the definition of "pure foraging, " (3) adherence to a dichotomy between foraging and agriculture, the result being that conscious and uncon- scious effects of exploitation on the demographic parameters of key resources is ignored, and (4) problems in defining the significance of ecotones. I consider the case of Penan hunter-gatherers of Borneo, a population which, by virtue of their reliance on the sago palm Eugeissona utilis, contradicts the conclusions of Bailey et al. and Headland. I consider salient aspects of Penan reliance on Eugeissona, and describe how Penan exploitation of this resource may posi- tively effect its availability. This case is seen to provide a challenge to the hypotheses of Bailey et al. and Headland, not only in the extent to which it contradicts their conclusions but, more significantly, in what it reveals about the assumptions upon which their hypotheses are based. This points to the need for greater precision in the definition of future hypotheses about foraging in tropical forests.

KEY WORDS: foraging; rain forest ecology; Borneo; Penan; Sago.

'Department of Sociology and Anthropology, Colgate University, Hamilton, New York 13346.

123

0300-7839/91/0600-0123$06.50/0 ? 1991 Plenum Publishing Corporation

124 Brosius

INTRODUCTION

In recent years, considerable progress has been made in producing predictive models of hunter-gatherer subsistence and social organization, based on rigorous analyses of the ecological context in which particular forag- ing populations exist. Attention to spatial distribution of resources and to temporal fluctuation in the availability of such resources has been particularly significant (Yellen, 1971; Jochim, 1976; Keene, 1981; Winterhalder and Smith, 1981). However, the ecological contexts in which such models have been applied has been limited. While much attention has been paid to arid, boreal, or arctic foraging adaptations, tropical contexts have been given in- adequate attention. Where attempts to consider tropical contexts have been made, significant problems of interpretation have emerged. This is the result of a basic misunderstanding of the relationship between salient aspects of tropical forest environments on the one hand, and human forager subsistence systems in such environments on the other.

Several articles have recently appeared which consider foraging in tropi- cal forests. Though not models of foraging as such, they address topics relevant to the construction of those models. The most comprehensive such discussion is that of Bailey et al. (1989). The authors consider whether it is possible for "pure" foragers to survive in tropical rain forests. They test the null hypothesis that "humans have never lived in the tropical rain forest in- dependently of domesticated plants and animals" (p. 60).

In surveying the ethnographic literature, Bailey et al. find that hunter- gatherers are either depending on agricultural products or occupy forest habitats that have been "modified by . . . shifting cultivation or invasion of introduced species" (p. 67). They conclude that "convincing ethnographic evidence is lacking that foraging peoples lived in tropical rain forest without reliance upon their own or neighboring peoples' cultivated foods" (p. 67). Likewise in considering archeological evidence, they conclude that it is:

. . .very possible that human adaptability did not include the capacity to subsist for long periods of time in tropical forests until the development of ways to alter the density and distribution of edible resources through domestication of plants and clearing of climax forest (p. 73).

In another recent article, Headland (1987) rejects what he terms the "isolationist" view of tropical foragers as "having always lived in such biomes, until recently isolated and separated from other peoples, and surviving solely on wild foods" (p. 463). He argues that:

Prehistoric hunter-gatherers either did not live in tropical rain forests, or else they lived there following an economy of symbiotic trade with food producers, exchang- ing forest products for cultivated plant foods. They may even have practiced cul- tivation themselves . . . Pure foraging, with no iron tools, no cultivation, and no

Foraging in Tropical Rain Forests 125

trade would at best have been a difficult and meager existence in closed tropical forests (p. 464).

More recently, Headland and Reid (1989, p. 44) have distinguished be- tween the "isolate model" and the "interdependent model," the view "that most, if not all, tribal peoples [in this context, foragers] have typically been in more or less continuous interaction with neighboring groups . . . for thousands of years" (p. 44).

The two implications of these arguments are that recently documented tropical foragers: (1) are only present in these biomes because they supple- ment their diets in some form by access to domesticated food sources, or (2) that their present adaptations depend to some degree on previous human disturbance of these habitats. Thus, presumed ancestors of such populations either: (1) did not live in rain forests, or (2) present foraging populations are the product of devolution from agriculturalist ancestors.

I believe that the conclusions reached by Bailey et al. (1989), Headland (1987), and Headland and Reid (1989) are incorrect, due either to a facile reading of the literature or to problems of a conceptual nature. In the following, I examine the conceptual bases of their arguments, and provide a case which should cast doubt on the conclusions reached by these authors, both empirically and in what it reveals about shortcomings in the formulation of their hypotheses. The case I consider is that of Penan hunter-gatherers of Borneo.

In this discussion, I refer in turn to Bailey et al. (1989), Headland (1987), and at points to Headland and Reid (1989). This is necessary be- cause these authors cover much of the same ground in the definition of their hypotheses, albeit in very different ways. However, I do note points of difference in the arguments of each where necessary.

Though the following comments are often critical, my intent is con- structive. The topic of foraging in tropical forests is one that has been dis- cussed for more than a decade. It is laudable that Bailey et al.2 and Headland have at last surveyed the data on a pantropical scale and at- tempted to clarify the issues that the presence of contemporary foragers in tropical forests raises.

THE HYPOTHESES OF BAILEY AND HEADLAND

Bailey's hypothesis rests on a linking of the general characteristics of tropical rain forest ecology to the "distribution and abundance of

2For the sake of brevity, I will hereafter refer to and cite "Bailey et al." as "Bailey." Likewise, all citations of Headland refer only to Headland, 1987 and, unless otherwise specified, not to Headland and Reid, 1989.

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resources exploitable by humans in tropical rain forest ecosystems" (1989, p. 60). After stating the hypothesis that "human foragers are unable to live in the tropical forests without recourse to domesticated plants and animals" (p. 60), Bailey summarizes several key features of tropical forest ecology. Among these are:

1. that tropical forests are the "most productive terrestrial ecosystems on earth" (p. 60), with the "greatest gross and net primary productivity" (p. 60).

2. that "rain forests are extremely efficient at rapidly cycling most nutrients" (p. 60).

3. that these forests have "the greatest biomass . . . and greatest species diversity of any terrestrial ecosystem (p. 60).

Commenting on the implications various of these features may have for human foragers, Bailey specifies features of tropical forest ecosystems which diminish the biomass available for consumption by both animals and human foragers. Among the most critical generaliza- tions about resource availability is that "the species with edible parts are widely dispersed in both space and time; costs of travel between plant and food sources tend to be high" (p. 61). This, in combination with the difficulties in processing, results in high handling costs for many vegetable foods. Bailey then discusses seasonality in tropical forests, noting that "this unpredictability and variability of food for human foragers in tropical rain forests . . . further reduce their capacity to sup- port hunters and gatherers" (p. 61).

Bailey notes that not only are carbohydrates: . . .the limiting resource for human populations in tropical rain forests . . . but sources of protein and calorie-rich fat may be equally restrictive at certain times or places (p. 61).

He characterizes most tropical forest animals as lean and lacking in fat, and thus "unlikely to be adequate substitutes for carbohydrates as sources of calories" (p. 61).

Having reviewed salient features of tropical rain forest ecosystems, and the implications for human foragers, Bailey suggests (p. 62) that:

If tropical rain forests presently seem able to sustain human foragers, it may be because long human occupation in most areas has created widespread disturbance of what were once climax habitats. Many of the plants that are now commonly exploited by humans in tropical rain forest areas may not have been present in current densities before the introduction of shifting cultivation into the forest.

These plants "have become established through natural dispersal, but their presence in the forest is dependent on environments of agricul- tural origin" (p. 62). Bailey concludes that "resources in undisturbed tropical rain forests may be so poor, variable, and dispersed that they

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cannot support viable populations of hunters and gatherers" (p. 62). The remainder of the article consists of a review of the literature in which Bailey searches "for substantial reports of hunters and gatherers living independently of agriculture in tropical rain forest" (p. 62).

Headland's argument is in some respects less problematic than Bailey's. The basis of his argument is that tropical forests are starch poor: "Wild starch foods, and especially wild yams, may be too scarce in [tropi- cal forest] . . . biomes to sustain independent hunter-gatherers without recourse to cultivated foods" (1987, p. 464). Headland bases his argument on a discussion of Agta foragers in the Philippines and on foragers else- where in Southeast Asia, and he also briefly reviews cases from Africa and South America. While I believe that Headland's argument holds for the Philippines, and that his distinction between rain forest and monsoon forest is useful, there are a number of troubling aspects of his more general argument.

In the following, I review the conceptual and empirical bases of the arguments of Bailey and Headland, focusing on four issues in particular: (1) assumptions about tropical forest ecology and human subsistence poten- tial, (2) the definition of foraging, (3) the distinction between foraging and agriculture, and (4) the nature of ecotones.

CRITIQUE OF BAILEY AND HEADLAND

Assumptions About Tropical Forest Ecology and Human Subsistence Potential

The conceptual foundation upon which Bailey's hypothesis of human subsistence potential in tropical forests rests is defined in his sum- mary of the salient features of tropical forest ecology: high species diver- sity, low density of particular species, and patchy distribution of those species (pp. 60-61). I suggest that extrapolating from such generalizations to the characterization of human forager subsistence systems in such en- vironments-a persistent practice in previous discussions of hunter- gather subsistence in tropical forest ecosystems (Binford, 1980; Hayden, 1981; Jochim, 1981)-is unwarranted. Such generalizations are essentially typological and biogeographical. This is the sort of model of environment which, as Bettinger (1980, p. 203) notes:

... set forth broad generalizations regarding the effects of certain qualities of en- vironment on human adaptation, many of them simply extending long-standing biogeographical explanations of adaptive patterns to human ecology.

128 Brosius

As Hutterer (1982, p. 177) notes, "There is no such thing as 'The Tropical Environment.'"

It is clear that tropical forest environments are extremely diverse floristically and that, relative to temperate forests, members of particular species tend to be widely dispersed rather than clumped. The problem comes when these features are extrapolated to features of human subsis- tence. It seems to be assumed that tropical forest foragers, inhabiting such a diverse biotic environment are relying upon a similarly great diversity of resources. In fact, they are relying upon very few plant and animal taxa to supply the bulk of their subsistence needs. It is true that they exploit a wide spectrum of seasonally available fruits and numerous varieties of minor fauna. But, despite the high diversity of tropical forest ecosystems, the bulk of their caloric and nutritional requirements is fulfilled by a limited range of plants and animals. Thus we must be cautious in simplistically equating environmental diversity with subsistence diversity. It is not possible to use the high diversity ascribed to a generalized and abstract model of tropical forest ecosystems in analyzing specific foraging adaptations. What is at issue here is the relationship between ecological organization (e.g., diversity, measures of dispersal, periodicity) and corresponding aspects of human subsistence organization.

In analyzing the subsistence base of tropical foraging populations, at- tention should be focused, not on the diversity of these environments, or on generalizations about the spatial and temporal distribution of resources, but on the characteristics of particular resources themselves. These include microenvironmental requirements and reproductive characteristics which determine their distribution, abundance, periodicity, and the ways they respond to human exploitation. The spatial and temporal patterns of dis- tribution of key resources being exploited by human foragers may differ con- siderably from the patterns characteristic of other forest taxa.3

Because Bailey is testing an hypothesis rather than presenting an argu- ment as such, it would appear that he has avoided such problems. Yet his hypothesis is nonetheless based on assumptions about the generic nature of tropical forest ecosystems. Headland does rather better in this respect, in the extent to which he considers the characteristics of a particular resource. But his argument is in itself flawed (1) in the way he extrapolates from the par- ticular case of Northeastern Luzon to tropical forests more generally, and (2) in basing that extrapolation on a single class of resource.

3In a later publication, Bailey (1990, p. 747) notes the need to devise tests concerning the possibility of foraging in tropical forests: "Detailed ecological studies of the density, distribution and life history strategies of edible resources in various rain forest environments would be an important start."

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The Criteria of "Pure Foraging"

The previous section has focused on the hypotheses tested by Bailey and Headland. A second problem with both Bailey and Headland's argu- ments are in the way they test those hypotheses. The definition of what they would consider to be hunting and gathering is vague, shifting, and inconsis- tent. In the abstract to their article, Bailey et al. state that "no peoples have ever been directly observed living independently of agriculture in tropical rain forest" (1989, p. 59), and suggest that there is no convincing ethnographic or archeological evidence for "pure foragers in undisturbed tropical rain forests" (p. 59, emphasis mine). In arguing that foragers cannot survive in tropical forests, the burden must be on these writers to clearly define the range of variation they would allow to be included under the rubric of "pure foraging." Instead they continually shift the focus of their arguments from agriculture, to technology, to management effects, to ecotones, to previous human disturbance, and it is not at all clear where they have established bounds. Bailey, in particular, proceeds on a case by case basis, explaining away every possible example of foraging in tropical forests. Rather than clarifying the issue of foraging in tropical forests, Bailey and Headland have, in this respect at least, confused it yet further.

To illustrate this, consider some of the range of definitions of "pure" (Bailey et al., 1989, p. 59) or "true" (p. 60) foraging-or departures from it-provided by Bailey. Bailey is consistent at those several points where he speaks of foragers "living independently of agriculture" (pp. 59-60, 62).4 Where inconsistencies are evident are where he refers to the criteria of foragers living in "undisturbed tropical rain forests" (p. 60) and of those who "lived in and drew subsistence solely from the tropical rain forest" (p. 72). Recall that Bailey concludes (p. 73) that foragers were not inhabiting tropical forests:

until the development of ways to alter the density and distribution of edible resour- ces through domestication of plants and clearing of climax forest.

This is something altogether different again. Bailey seems to consider al- terations of the density and distribution of edible resources to be synonymous with domestication and forest clearance, a very naive assump- tion.

The range of definitions Headland provides for what he calls "pure foraging" is less consistent still. He first speaks of foragers who have

4Elsewhere, for instance, Bailey et al. speak of foragers who "subsist . . . independently of domesticated plant or animal resources" (1989, p. 60); "the effects of some reliance on domesticated foods and contact with horticultural neighbors" (p. 60); foragers who are "in contact with horticulturalists and have relied to some extent on domesticated plants and animals for a very long time" (p. 60); and those "without reliance upon their own or neighboring peoples' cultivated foods" (p. 67). These are largely consistent with each other.

130 Brosius

"lived completely independent of cultivated foods" (1987, p. 463), and those who are "surviving solely on wild foods" (p. 463). These may appear to be two sides to the same coin but, as I believe the following discussion will show, they can mean two very different things. Elsewhere (p. 464) he cites Barnard's reference (1983, p. 194) to notions of "natural purity and cultural pollution." He also speaks of "independent hunter-gatherers without recourse to cultivated foods" (p. 464), of "symbiotic trade with food producers, exchanging forest products for cultivated plant foods" (p. 464), and, finally, of "pure foraging, with no iron tools, no cultivation, and no trade . . ." (p. 464). The mention of iron in particular introduces a potential distortion into his argument, in that it seems we must now eliminate foragers on technological grounds, independent of the charac- teristics of the resources they are exploiting.

Bailey et al. are also vague about the significance of the degree to which foragers trade with agricultural populations and the content of this trade. Bailey is unclear about specifying different types or degrees of reliance on agriculturalists, and how this variation might affect the test of his hypothesis. He states, for instance, that he is unable to find "any groups in Southeast Asia who are currently living independently of agriculture and trade" (1989, p. 64). He eliminates several groups from consideration by virtue of their involvement in trade, without specifying the precise content of this trade. Headland and Reid argue that "foraging groups were heavily dependent upon both trade with food-producing populations and part-time cultivation or pastoralism" (Headland and Reid, 1989, p. 43). They frequently specify trade for agricultural products, but are inconsistent when it comes to examining the ethnographic record. The point here is that it is very possible to be involved in vigorous trade relationships, with no agricultural products entering into this trade at all. In the final analysis, the conclusions reached by Bailey and Headland are inconsistent with the data they present. Headland (1987, p. 486) concludes that:

The symbiotic relationships found today throughout the world between tropical forest hunter-gatherers and food producers are therefore not a recent phenomenon.

I fully agree with this. But this is not at all the same as saying that they could not be existing in those forests otherwise.

The Dichotomy of Foraging and Agriculture

The inconsistency in a definition of foraging to which I have referred, derives in part from the fact that Bailey and Headland speak of agriculture and foraging as if these two modes of subsistence were

Foraging in Tropical Rain Forests 131

strictly dichotomous. In fact, the distinction is not so clear, either con- ceptually or with respect to the biological and demographic processes of the resources being exploited (see Hutterer, 1983). Human foragers are under ecological constraints just as any other species, but differ from other species in the degree to which they may be managing resources. Bailey et al. (1989, p. 62) argue that:

If tropical rain forests presently seem able to sustain human foragers, it may be because long human occupation in most areas has created widespread disturbance of what were once climax habitats.

Here he appears to be referring to the disturbance caused by agricultural clearance, suggesting that this has affected the densities of certain plants to the benefit of foragers. In reference to the New World, he argues that "forests that have been substantially modified by millennia of shifting cul- tivation and centuries of invasion by introduced species" (p. 198). This is true enough (see Roosevelt, 1989). But Bailey seems to ignore the unrecog- nized effects that result from the exploitation of tropical forest species by human foragers, and ignores the possibility that certain populations may intentionally be managing resources which they exploit, or unconsciously affecting the population dynamics of those resources. As Hutterer (1982, p. 175) notes, "certain aspects in the patchy distribution of plants in tropical forests may be an effect of long-range and continuous human presence."5

In short, it is necessary that the criteria for what is considered "pure foraging" be clarified. In particular, to what degree should we allow for the effects of conscious or unconscious resource management? The issue here, and the aspect that requires specificity, is the definition of what is meant by "undisturbed" forest. We need to ask whether, why, or to what extent either the unconscious effects of exploitation or the conscious management of resources should be allowed in our considera- tion of tropical forest foragers. Where, in short, should the line be drawn? If we would disallow resource management, we must ask whether there are foragers in any ecosystem which do not manage resources to some extent, or whose exploitation of a certain suite of resources does not have some effect on the long-term demographic characteristics of those resources. We may be forced to conclue that foragers have not ever existed on any biome. It may indeed be true, as Bailey et al. con- tend, that humans did not occupy tropical forests "until the development of ways to alter the density and distribution of edible resources" (1989,

5In a latter publication, a reply to a critique of Bailey et al. (1989) by Patricia Townsend (1990), Bailey seems to indicate that he was being purposefully vague. He states that "In part because we wanted to make a provocative challenge to our colleagues, we deliberately ignored the lack of a clear distinction between living by hunting and gathering and subsisting by cultivated food crops" (Bailey, 1990, p. 747).

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p. 73). But there are certainly other ways to do this than "through domestication of plants and clearing of climax forest."

Exploitation, while in the short-term depressing resource stocks, may have profound effects on the demographic characteristics of a given resource (Caughley and Lawton, 1976; Lubchenco and Gaines, 1981, p. 414; Getz and Haight, 1989). In fact, the productivity of a resource may be enhanced in the long-term by exploitation, with important implica- tions for (1) future edible biomass available to foragers, and (2) the long-term efficiency of exploitation (Ricker, 1958; Beddington, 1979, p. 308; Pitcher and Hart, 1982). In reference to plant-herbivore systems, Caughley and Lawton (1976, pp. 162-163) discuss the impact which graz- ing may have on the partitioning of resources within different parts of a plant, and how grazing may result in compensatory growth. They con- clude that:

. . .the long-term consequences of these changes in resource allocation for the population dynamics of plants are largely unknown. But they are obviously difficult to accommodate within the existing framework of Lotka-Volterra models (p. 163).

Beddington (1979, p. 308), discussing harvesting as a predator-prey system which may be manipulated to produce a sustainable yield, notes that "judicious manipulation of the age structure of a population can substantially increase the growth rate and hence sustainable yield." Harvesting above a certain level may of course result not simply in short-term resource depression, but resource depletion as well (p. 308), to the long-term detriment of exploiters.

The precise way in which exploitation affects the population dynamics of various resources will vary with the particular type of resource-as a function of its reproductive strategy-and with different intensities of exploitation. This applies regardless of what type of ecosys- tem foragers are occupying, or at what level of intensity they are exploit- ing it. On this basis, it is almost irrelevant whether or not alterations in the population dynamics of a species are due to conscious resource management.

Understanding that the exploitation of resources may affect their popula- tion dynamics has important implications for speculations about the availability of such resources to hunter-gatherers inhabiting rain forests prior to the ad- vent (at least locally) of agriculture. Hunter-gatherers are resource managers, but they are also opportunists. More to the point, they are in a position to respond opportunistically to changing circumstances, among which may be the sudden or gradual availability of agricultural products. If agricultural products become available, we would expect foragers under most circumstances to opt to take advantage of these, either because it is energetically more efficient to do so or, perhaps, because such products are more palatable. This has im-

Foraging in Tropical Rain Forests 133

plications for the availability of non-cultivated food resources. It is plausible to suggest that a reliance on agricultural products among contemporary forag- ing populations has resulted in alterations in the conscious or unconscious management of forest resources. Having turned to the consumption of agricul- tural products as the result of involvement in trade networks, foragers may let the management of forest resources go, thereby making these foods less available. Such resources may thereby drop out of the subsistence repertoire because their management is abandoned. Interpretations of resource distribu- tion must be made with this consideration in mind. The distributions of resour- ces we observe today may be very different from what they were before exploitation and management were abandoned. Thus, contrary to the assump- tion that hunter-gatheers could only have occupied tropical forests with the advent of agriculture, it seems that the opposite scenario is equally likely: that it is agriculture itself which has led to the current dearth of carbohydrate resources in most tropical forest ecosystems.

Bailey et al. state (1989, p. 62) that:

Many of the plants that are now commonly exploited by humans in tropical rain forest areas may not have been present in current densities before the introduction of shifting cultivation into the forest.

It is clearly possible to argue the opposite: that indeed many plants used by foragers were possibly present in greater density prior to the incursions of agriculturalists into, or even adjacent to, those ecosystems. This is ob- viously contrary to the notion that hunter-gatherers could only have oc- cupied tropical forests with the advent of agriculture. Thus, using contemporary foragers to test this hypothesis, while a necessary starting point, is not sufficient. Contemporary foragers do not constitute a repre- sentative sample of foraging in tropical forests and therefore do not con- stitute a falsification of Bailey's hypothesis.

There is another reason as well why examining contemporary foragers may not be a sufficient test of either hypothesis. All the cases of Southeast Asian foragers considered by Headland are populations inhabit- ing upland areas. While the Agta and Penan do exploit what are floristi- cally and structurally lowland forests, they are in deeply dissected foothill or mountain areas, and these populations exploit resources over a wide range of elevations. They do not inhabit or exploit the extensive alluvial or coastal areas which are today dominated by agricultural populations.6

6Here I would highlight the word extensive, by which I mean such extensive alluvial areas as the Central Luzon Plain or the Cagayan Valley in the Philippines. While Agta, for instance, do frequently live on or near the coast and along rivers, the coastal plain in Northeastern Luzon is generally very narrow, as are river valleys.

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Significantly, some of the most productive Dioscoreaceae (Dioscorea pen- taphylla, D. bulbifera, D. hispida, D. luzonensis) occur frequently or ex- clusively near streams, along river terraces, or in alluvial areas (Burkill, 1954, pp. 293-347; Navin Rai, Melinda Allen, personal communication). At present we do not know enough about the reproductive ecology of Dioscorea or other wild yams to know whether they are prevalent in riparian and alluvial environments because they prefer ecotones, because of edaphic factors, or for other reasons. The significance of this pattern of distribution is that the ideal habitats for wild yams are precisely those areas presently occupied by agricultural populations, areas which have been cleared throughout much of Southeast Asia. The narrow strips of coastal or riparian environment currently occupied by foragers are not at all representative of circumstances which existed prior to the invasion of agricultural populations.

For similar reasons, I believe that Headland's dichotomy between the "isolationist" (p. 464) view of hunter-gatherers-that they have lived out of contact with other peoples until recently-and the "alternative hypothesis"-that such peoples have depended on external dietary sup- plements or on agricultural production themselves-is a false one. All Headland need do is demonstrate that Agta (or other tropical foragers) have been in long contact with agricultural neighbors, something that we already know to be the case. But this is not a sufficient test of the hypothesis: it has nothing to do with whether or not foragers can exist in nutritional isolation without recourse to trade for carbohydrates, which is, at base, an ecological issue. Such dichotomies ultimately obscure the very types of factors that we should be investigating.

The Nature of Ecotones

As Bailey reviews the ethnographic literature, he eliminates several groups from consideration because they exploit ecotones of various types. While substantial exploitation of particular types of ecotones should per- haps eliminate consideration of some groups, this is a matter of degree and kind. Bailey et al. for instance, refer at one point to rivers (1989, p. 66). I fail to see how rain forests can exist without being drained. Rivers and streams are an integral part of rain forest ecosystems. To generalize about the characteristics of ecotones in terms of their implications for human foragers, and to eliminate from consideration those foragers who exploit them, is not warranted. Rather, it is necessary that we define the characteristics of particular types of ecotones in specific ecosystems. This

Foraging in Tropical Rain Forests 135

is never an easy task: as Margalef (1968, p. 39) has noted, "ecotones often disappear when we look for them."

PENAN HUNTER-GATHERERS OF BORNEO

Throughout interior central Borneo, there exist a variety of forest-dwell- ing hunting and gathering societies variously known as Penan or Punan.7 Nearly all of these groups have now settled and taken up agriculture, but many have remained nomadic up until recent decades.8

Though there is a great degree of variability in many aspects to settlement and social organization, the subsistence base of most groups is remarkably uniform. The following discussion concerns the Penan of Sarawak, East Malaysia.

The Penan of Sarawak are themselves divided into two main groups speaking subdialects of the same language: Eastern and Wesern Penan (Needham, 1972). I conducted field research among the Penan Gang, a subgroup of Western Penan numbering some 900 individuals in eight com- munities, who inhabit the Usun Apau plateau between the Balui and Baram rivers.9 There are a number of significant differences between Eastern and Western Penan with respect to salient features of settlement and social organization. In the smaller size of bands, the greater frequency of move- ment, and in other features of settlement and social organization, Eastern

7For clarification of the issue of nomenclature in the use of the terms Penan/Punan see Brosius (1988). In central Borneo, the terms Penan or Punan are frequently used as ethnonyms by these groups themselves, but they may also be applied as exonyms by agriculturalists in a generic sense to refer to all hunter-gatherers, even those which have been settled for many generations. Thus, such groups as Sihan, Lisum, or Bukat may be referred to as Punan (or Penan) Sihan, Punan Lisum, or Punan Bukat (see Needham, 1972; Hildebrand, 1982; Sellato, 1989; Brosius, 1990; Rousseau, 1990 for descriptions of foraging societies in central Borneo and discussions of their place in the economies of the region).

8Penan in Sarawak began to settle in large numbers in the 1950's and 1960's. Today only 5% are still fully nomadic. In the Belaga District of Sarawak where I conducted my fieldwork, the last nomadic Penan settled in 1969-1970. All these groups presently rely upon agriculture to some extent, though the degree to which this is the case is variable from community to community. The primary crops grown today are cassava and rice. The community where I conducted my fieldwork began to practice agriculture in 1969 and presently relies upon cul- tivated products for approximately 6 months of each year. During the remainder of the year they exploit traditional non-cultivated forest products.

9Fieldwork was conducted from November 1984 to September 1987. I lived in the Penan Gang community of Lang Jek (along the middle Seping River on the southewest margin of the Usun Apau plateau) for a total of 24 months and developed fluency in the Western Penan dialect. I also traveled to and censused all but one of 19 Western Penan communities throughout the interior Belaga and Baram Districts, and made brief visits to communities of other presently or formerly nomadic hunter-gatherers (Eastern Penan, Punan Busang, Bukat, and Sihan).

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Penan conform more closely than Western Penan to generalizations made about foraging societies.10

Certain features of Western Penan subsistence, settlement, and social organization make them unique among recently documented foragers. These include: (1) large bands of 60-200 individuals, (2) long occupation of settle- ments, often for periods of over 1 year, (3) long-term stability of band com- position, and (4) what appears to be a nascent form of aristocratic leadership."

In the interior districts of Sarawak, longhouse-dwelling swidden agricultural groups-Kayan, Kenyah, and others-are settled along the banks of the major rivers.12 In contrast, hunter-gatherers such as the Penan are mostly to be found in upper tributaries, areas which are characterized by mountainous, forested ter- rain. A feature which distinguishes Penan (and other Bornean foragers) from those elsewhere in Southeast Asia, and indeed in much of the tropics, is that whereas groups such as Agta and Semang live and forage in close proximity to agricultural settlements, Penan inhabit areas in the deep interior, usually one to four days' walk from the nearest agricultural settlements. This is by no means to suggest that these groups are cut off from contact or trade with agriculturalists. Indeed, trade is of vital importance to Penan. However, unlike most other tropical foragers, this trade does not involve the exchange of forest products for food. Penan trade various forest products for items such as tobacco, metal, cloth, salt, and flashlight batteries, but not food items such as rice, corn, or cassava. With respect to food, Penan are wholly self-sufficient and do not require supplements from trade with longhouse peoples.13

Both Bailey and Headland refer to Bornean foragers in support of their hypotheses. Bailey (p. 64) quotes Needham's statement that

101 would note that my information on Eastern Penan must be considered preliminary since I have visited Eastern Penan on only two brief occasions, a total of 6 days. Even in these short periods of observation, however, significant differences between Eastern and Western Penan subsistence, settlement, and social organization were clearly evident.

lSee Brosius (1990) for a more extensive discussion of the salient features of Western Penan society. The issue of aristocratic leadership among Western Penan is problematic, particularly in that it coexists with strongly egalitarian principles.

12At least in those areas occupied by stratified societies such as Kayan and Kenyah. In contrast, Iban often inhabit smaller tributaries at some distance from major rivers.

13That trade for agricultural products has not been an important part of the traditional Penan subsistence regimen is indicated not only by the statements of informants, but also by the absence of any statements to this effect in the literature. Further, given the great distance of Penan settlements from agriculture settlements both today and in the past, reliance upon trade for agricultural products is highly inefficient. In any case, Penan visits to longhouse communities only occurred two or three times a year at most: this is changing somewhat today due to the penetration of logging roads into areas occupied by Penan. Another reason Penan do not trade for food is a persistent (if unfounded) fear of poisoning. On visits to longhouse communities, Penan will on occasion take some rice from trusted trading partners, but generally only enough to last for the duration of the trip back to their own communities.

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Penan/Punan "need to trade with settled peoples . . . in order to remain nomads" (1972, pp. 177-178), and repeats Hoffman's contention that these peoples are devolved horticulturalists who "possibly even became nomads in order to trade" (1984, p. 142). Headland and Reid (1989, p. 49) state that "Hoffman ... dispels any idea that the hunter-gatherers in the interior of Borneo were independent 'wild people of the woods,'" and cites Hoffman's contention (1986, p. 102) that "Punan groups . .. arose initially from the demand for various jungle products desired by Chinese."

Since Bailey et al. (1989), Headland (1987), and Headland and Reid (1989) each cite Hoffman's work, it is necessary to briefly discuss its ac- curacy. Hoffman contends that the existence of peoples such as Penan in Borneo is explained exclusively with reference to their role as providers of forest products in local trade networks. It is indeed the case that Penan and other Bornean foragers have long occupied a specific niche in the economies of interior Borneo. Such peoples have been a major source of forest products which are traded to longhouses and thence to the coast for consumption or export. Based on fragmentary and incorrect data, however, Hoffman has taken this argument to extreme lengths in claiming that Penan/Punan exist primarily to trade, that trade is their raison d'etre. Hoffman's contentions about the ethnogenesis of Bornean foragers are entirely misinformed and add up to little more than an exercise in con- jectural history.14 This is in large part due to his choice of field method: a series of brief visits to perhaps a dozen Penan/Punan communities over a period of 15 months. A broad-ranging survey may be an important preface or supplement to in-depth field research within a single com- munity, but it is no substitute. By survey alone, field data inevitably lack depth and are of limited value. Given the enormous travel times in East and Central Kalimantan where Hoffman worked, he cannot have spent more than a couple of weeks with any single group. As a result, Hoffman never developed proficiency in any Penan/Punan language.15 Because of his choice of field method, Hoffman misapprehends numerous aspects of Penan/Punan subsistence, settlement, social organization, religion, language, ethnicity, and trade. Several examples can be given to illustrate this.

14In this discussion, I reiterate in brief a number of points made in a previous review of Hoffman's work (Brosius, 1988; see also Kaskija, 1988; Sellato, 1988 for critiques of Hoffman's characterization of Bornean foragers).

15Nowhere in the book does a single item of Penan/Punan vocabulary appear, with one exception, and there it is used incorrectly (payau, p. 26). Elsewhere Hoffman provides only Indonesian vocabulary, presenting it as if it were Penan/Punan, such as when he tells us that the traditional Penan/Punan shelter is called a pondok (p. 30). Numerous other examples abound-babi hutan, sumpit, cawat, prahu, parang, and others.

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Hoffman makes a number of assertions about the linguistic affiliations of various Penan/Punan groups, and about the linguistic relatedness of Penan/Punan dialects to those of sedentary agriculturalists. Nowhere does he present linguistic evidence to support these assertions. Given his chosen field method, one would at least have expected Swadesh word lists to have been collected, and perhaps included in an appendix. Such data would have en- hanced his argument tremendously-or perhaps not-but would certainly have been invaluable for others in assessing the validity of his arguments regarding both the grouping and subgrouping of Penan/Punan populations and their relationship with other Bornean populations. Nowhere do we have any evidence that such word lists were collected.16 This is a critical area of omission, since a key part of Hoffman's argument is based on the asser- tion-or on the creation of the impression-that adjacent Penan/Punan and sedentary agricultural groups speak nearly identical languages (pp. 14, 20, 24, 25, 39, 58, 59, 60, 62, 63). For instance, Hoffman attempts to convey the fallacious idea that the cultural and linguistic differences between Kenyah Lepotan and Punan Oho, and Kenyah Lepo Timai and Lisum are negligible (p. 39). Such an assertion is simply erroneous.

In Sarawak, there are two primary dialect groups of Penan (ignoring for now the Punan Busang and sedentary Punan Bah) which Needham (1972) termed Eastern and Western Penan. These two dialects, though somewhat different, are mutually intelligible. What is significant is that this relatively unitary linguistic unit is surrounded by sedentary agricultural peoples of over a dozen linguistic groups: Kelabit, Berawan, Kayan, Badang, and others. This is clearly a much more complex situation than that described by Hoffman.

In the scant two pages in which he discusses "linguistic affinities" (pp. 19-20), Hoffman notes accurately that various Penan/Punan languages vary widely, and may be more closely related to the dialects of various sedentary agricultural groups than to those of each other. In Sarawak for instance, the Western Penan and agriculturalist Badang languages are much more closely related to each other than either are to the completely mutually unintelligible Punan Busang language. Certainly I would agree with Hoffman that "The Punan do not form any sort of linguistic isolate; they do not speak languages unrelated to those spoken by sedentary agricultural peoples" (p. 20). It is the conclusions that Hoffman draws from this that are inaccurate. He states that "linguistic evidence does not support the assumption that the 'Punan' com- prise a single, uniform people who are ethnically distinct from sedentary agriculturalists" (p. 20). What Hoffman is doing here is linking the correct idea that the Penan/Punan are not a single people (which has never been

16In two instances Hoffman mentions word lists (pp. 15, 19) but it is unclear whether these were collected by him or by others.

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claimed by any reliable observer) with the fallacious claim that they are in- distinct from sedentary peoples.

Penan languages in Sarawak are part of the Kenyah language family. The question then is, would this not appear to support Hoffman's contention that Penan/Punan are retrograde agriculturalists? Clearly one could argue for the opposite perspective, that many contemporary agricultural societies derive from hunter-gatherer populations. In fact, this is what oral traditions suggest for groups such as Kenyah Lepo Tau (Whittier, 1973) and Sebop. It is also more consistent with historical trends, since there are a large number of former hunter-gatherers in both Sarawak and Kalimantan who have set- tled in historical times, as Hoffman himself notes. It is often assumed that the process of settlement of nomads is largely a recent, post-colonial phenomenon. In fact, it is likely that this process is of much greater time depth. One cannot ignore, either, the relative valuation between rice and sago assumed by many Bornean peoples, for whom success in rice cultivation is held in high regard, and the consumption of sago the precise opposite. Penan are well aware of this attitude, and the rice ethos may have been a force in the gradual sedentarization of hunter-gatherers. The point here is that rarely if ever does the process work in reverse fashion, i.e., successful rice farmers abandoning agriculture for a sago-based subsistence system.

We are further given the impression by Hoffman that the relationship between nomadic and sedentary communities is of great time depth. In reality, Penan and Punan with whom I am familiar have generally formed close relationships with a series of longhouse communities through time. Such relationships may endure for several generations, but they are equally likely to be severed after relatively brief periods or to be intermittent. The Penan Gang, over the past century, have variously had close relationships with Seping, Sebop, Lirong, Lahanan, Sambop, Uma Pawa, Kayan, and others. Furthermore, whereas many Penan groups do remain in the same general area over many generations, even when longhouse communities with which they have been associated move away, other Penan groups move great dis- tances, to areas which they never previously inhabited. This is clearly a very different picture than that presented by Hoffman.

With regard to Penan/Punan subsistence, Hoffman again presents a high- ly distorted picture. For instance, Hoffman speaks of "food gathering" as a women's activity (p. 44). One of the more significant features of Penan sub- sistence is that, except for occasional fishing, the role of women is rather min- imal and circumscribed, limited primarily to participation-with men-in sago processing. Groups of women almost never travel alone into the forest unaccom- panied by men or boys. Elsewhere (p. 29), Hoffman speaks of the production of salted sun-dried fish as a traditional Penan/Punan enterprise. This is decidedly not the case, as anyone who would try to prepare this in the shaded, humid forest

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would soon discover. Hoffman also speaks of "two species of large wild deer called payau and nrsa" and "the kancdil or mouse deer" (p. 26). No person who has more than a fleeting familiarity with the subsistence economies of interior Borneo, or has familiarized themselves with the ecology of Bornean forests, would make such a mistake. Payau is a generic central Bornean term for the Sambar deer (Cervus unicolor), while rusa is the Malay term for this same species. There is also the small barking deer (Muntiacus munqac), called talao in many central Bornean languages, which seldom stands taller than 25 inches at the shoulder. Finally there is a mouse deer (Tragulus sp.), called kancil or pelandok in Malay and pelanuk in many central Bornean languages.

Hoffman's treatment of Penan/Punan social and political organization is equally facile and inaccurate, reflecting the extension of generic assumptions about hunter-gatherers to the Penan/Punan. He asserts that these groups have "fairly uniform patterns of social structure and political organization" (p. 36). In fact, Penan/Punan social-political organization is highly variable. Undoubtedly, some groups, such as Eastern Penan in the Baram River watershed, form small bands of fluid comosition, and lack strong institutions of leadership. However, two groups as culturally and linguistically dissimilar as Penan Gang and Punan Busang share several notable similarities which are quite at odds with the description provided by Hoffman. One feature these groups share is relatively large band size-up to 200 members-and long-term stability of band composition. These are certainly not "amorphous unit[s] with fluid composition and vague social boundaries" (p. 37), as they are depicted by Hoffman. With regard to leadership, both Penan Gang and Punan Busang claim the existence of aristocrats, and this has a strong genealogical basis. Among these groups, leadership is not "temporary and ad hoc" (p. 36), and Penan/Punan groups are not "acephalous unit[s] of identity" (p. 37).

On the subject of ethnonyms, Hoffman makes the completely fallacious statement that "the word Punan was far more commonly a term of reference applied to nomads by sedentary peoples than an actual label of identity for the nomads themselves" (p. 17). He further states that they

. . . will on occasion, refer to themselves as Punan, but they are usually more prone to speak of themselves using some local lexeme meaning "us." In either case, Punan is rarely a meaningful ethnic name in the minds of peoples so termed (p. 17).

Among both Eastern and Western Penan in Sarawak, the autonym they apply to themselves is Penan, and Punan Busang refer to themselves as Punan.

Hoffman further errs in asserting that geographic referents (usually river names) attached to ethnonyms are "rarely a label of identity by which people refer to themselves" (p. 18), and that "trying to ascertain the 'real names' of Punan groups was a matter far more important to me than it was to the Punan themselves" (p. 18). Such statements are entirely misinformed. Any given Penan/Punan group may refer to itself by any of several different names, but this does not mean that these names are unimportant. It is true that there is no single

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name which is the name for any particular group. What Hoffman failed to recog- nize is that various names are used in a sort of segmentary fashion, with an his- torical and genealogical referent. To give a brief example, Penan in Lang Jek may refer to themselves as Penan Apat, Penan Gang, Penan Belaga, of Penan Lang Jek. No single name is the correct name, but depends on the immediate context of inclusiveness in reference to other Penan groups. This inclusiveness is an artifact of historical and genealogical commonality.

In pressing his point concerning the relatedness of Penan/Punan to sedentary communities, Hoffman further errs in the way he interprets state- ments by his informants. He presents numerous examples where individuals assert their relatedness to neighboring agriculturalists (pp. 24, 38-39, 58-60, 62). I myself have heard many such statements made by Penan, Kayan, and Kenyah. A Penan, for instance, may claim emphatically that a certain Kayan is a "real, true sibling" (atak padi lan), or that people of a certain longhouse are of the same origin (asan) as themselves. But no competent anthropologist would accept such statements at face value. In some cases, such claims may be made because of the past temporary fosterage of a Penan child by a par- ticularly longhouse family. Another reason may be a past (sabila) relationship, originating in a blood pact made by two individuals. Third, such statements may be the result of actual genealogical relationships resulting from particular marriages between Penan and longhouse persons, often more than a century previously. The most common context in which such statements are heard are when Penan and longhouse peoples are together. In such cases, the assertion of kinship is a matter of etiquette. On several occasions, Penan and Kayan have reciprocally made such claims in my presence. When later asking Penan about the genealogical particulars of such purported relations, I was told that they were not actually kin, but that this was said out of politeness. Genealogical links between Penan/Punan and sedentary communities do exist, but these links are uncommon and occur between members of two clearly distinct com- munities. This does not represent the transition of agricultural communities into hunter-gatherers, nor does it indicate a fluid and permeable boundary between nomadic and sedentary communities.17 It would be useful to know

17In this regard, Hoffman further errs in making sloppy use of the literature. For instance, in quoting Beccari's statement (1904, p. 302) concerning the relatedness of Kejaman, Sekapan, Kayan and "Punan," and Brooke's comments (1866, Vol. I, p. 73; Vol. II, p. 301) on the relatedness of "Punan" and Melanao, Hoffman fails to realize that it is the sedentary, agricultural Punan Bah who are being referred to (p. 62). He also misrepresents Urquhart's account (1957) concerning the relatedness of Penan Silat and Kenyah Nyamok (p. 62), though this is not entirely Hoffman's fault; Urquhart's account itself contains a number of misleading statements. I have collected this same account from both Penan and Kenyah, with further genealogical details. It refers to the marriage of a Kenyah woman and a Penan man some six generations before, rather than to any purported isomorphism between these two groups.

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the context of the statements Hoffman records, whether they were made in the presence of Kayan, Kenyah or other longhouse-dwelling guides. Hoffman apparently took such statements literally without perceiving what was behind them or attempting to confirm them.

Finally, Hoffman's work is flawed by a number of serious omissions. For instance, the importance of trade among Southeast Asian hunter- gatherers is not an issue which has been ignored by anthropologists (Fox, 1969; Benjamin, 1973; Endicott, 1974; Hutterer, 1974, 1976, 1977; Dunn, 1975; Estioko-Griffin, 1975; Peterson, 1977, 1978a,b; Rambo, 1979). Yet Hoffman does not cite any of this literature.

The preceding statements point to only a few of the shortcomings of Hoffman's treatment of the ethnogenesis of Bornean foragers. It is apparent that Hoffnan refers to published ethnographic and historical accounts in a partial manner, ignoring statements that contradict his argument. Through both omission and commission Hoffman thus misrepresents the ethnographic record. My ap- praisal of Hoffman's work is not a matter of disagreement over interpretations, but a critique of the factual foundation upon which those interpretations are based. Having now considered Hoffman's work, let me turn to Penan subsistence.

Sago starch derived form the palm Eugeissona utilis has traditionally been the primary source of carbohydrates for Penan. It is this resource more than any other which determines the location of Penan camps and the frequency of their movement.18 The Eugeissona palm occurs throughout interior central Borneo and has a wide elevational range. It is found in greatest concentration on steep ridges and slopes, where it grows in dis- persed groves interspersed with other forest vegetation. As with other sago palm species, the Eugeissona palm stores starch in its trunk. As the palm

18Here again, serious deficiencies in the information provided by Hoffman are evident. In contradiction to earlier statements that Penan/Punan are to be found at no great distance from longhouse settlements, Hoffman states that they dwell "in deep forest areas" (p. 89), by which he presumably means beyond hunting range of longhouse peoples. He asserts that Penan/Punan do not live in the deep forest in order to hunt, since they could as easily find an abundance of pig in areas adjacent to longhouses. This is an arguable, though not necessarily fallacious, point. Let us grant him this. The argument then is that, since Penan/Punan are not in the deep forest to hunt, they can only be there for the purpose of collecting forest products for trade. Hoffman conveniently forgets to mention the central place of Eugeissona in Penan/Punan subsistence. Pig can indeed be found just about anywhere if one looks hard enough (and one does have to look rather harder in the vicinity of longhouses). But, unlike pig, sago is immobile. Penan/Punan must thus locate themselves in proximity to concentrations of Eugeissona. They have a clear idea of the relative abundance and location of sago groves throughout their foraging areas. Penan/Punan explicitly and consistently state that it is the relative abundance of sago in various locations in the forest that determines the location and duration of their settlements. Had Hoffman not heard this himself, he could have found numerous statements to this effect in the literature.

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grows, increased amounts of this starch are produced and deposited. After 10-15 years, concentrations of this starch are at their maximum. The palm flowers and fruits draw on these starch reserves to sustain fruit production. If felled and processed in the early stages of flowering, large quantities of starch can be extracted. The processing of Eugeissona for starch is a rela- tively efficient mode of subsistence. Though yields do vary somewhat, the amount of starch derived from any given episode of processing appears to be fairly consistent. The average starch/pith ratio is slightly above one part starch to every four parts of chopped pith. Three persons working for an average of six hours can process over 100 lb of starch per day.19

It may be supposed that the exploitation of sago by Penan would result in the eventual depletion of this resource in a particular area. How- ever, an examination of the reproductive ecology of the Eugeissona palm reveals otherwise. Eugeissona generally occurs in dense clumps of three to six trunks per clump, elevated on aerial roots. This clumping habit is a product of its reproductive strategy: Eugeissona reproduces both vegeta- tively and through the production of seeds. Holttum (1954, pp. 22-23), dis- cussing the vegetative reproduction of a species of Eugeissona in peninsular Malaysia, noted that "these palms have almost adopted a bamboo habit." Thus, while the processing of sago in a particular area over a period of several months may lead to temporary depletion, this harvesting strategy does not negatively affect its long-term growth. In fact, the thinning of Eugeissona in the process of exploitation may actually enhance the produc- tion of starch and viable seed, as has been observed in the reproductively similar Metroxylon palm (Barrau, 1958, p. 38; Flach, 1977, p. 163).20 This is not to say that Eugeissona cannot be over-harvested and thus depleted. Indeed it can, particularly when the harvesting cycle in a stand is too short and clumps are not allowed to sufficiently recover before being reharvested. For this reason, Penan seek to maintain a sound harvesting strategy which avoids a foreshortened harvest cycle. When the sago in one area has been depleted, it is left to recover over a period of years. The Penan attitude with regard to Eugeissona is one of explicit stewardship, a stewardship which extends to specific clumps or groves of palms. Of significance here is the Western Penan concept (and practice) of molong, "to preserve" or

19Such episodes of sago processing generally involve one person washing the pith while others chop it from half-sections of a trunk.

20This is in contrast to non-clonally reproducing sago palm genera such as Caryota. Caryota reproduces only through the production of seed (McCurrach, 1960, p. 36) and, since plants selected for sago extraction are felled prior to the setting of seed, the impact of human exploitation on Caryota populations is considerable. Not only is the tree itself destroyed, but all reproductive potential as well. This is further exacerbated by the fact that trees are frequently felled while immature in order to get the edible leaf bud. Caryota palms are thus highly susceptible to overexploitation and rapid depletion (see Yen, 1976, p. 161).

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"to foster." This practice applies both to fruit trees of various types and to Eugeissona. Frequently when traveling in the forest a person will spot a tree which has not been claimed and will mark it, thus reserving it for future harvest (and preventing premature harvest for the purpose of ex- tracting the edible leaf bud). Even young children actively molong trees, and by adulthood may have accumulated several dozen fruit trees and sago clumps. The concept of molong is applied in a broader sense as well. As noted, once they have depleted the sago in a particular area and moved on to another watershed, the sago in the previously exploited area is left to recover (often for a decade or more) and is said to be molong.21

Though the management of Eugeissona is both conscious and pur- posive, it occurs at a relatively low level of intensity. For instance, Penan do not actively seek out Eugeissona clumps in order to thin them. Rather, all actions which can be defined as management occur only as the result of either exploiting a clump or, occasionally, when passing by in the course of some other activity. Though low in terms of time expenditure, the long- term demographic effect of such management is nevertheless considerable.

In addition to its occurrence in primary forest, Eugeissona is often managed as a famine food by longhouse peoples, and is very prevalent in areas of secondary growth. The areas currently occupied by Western Penan-the Plieran, Seping, Danum, Linau, Belaga, and Silat river val- leys-were previously occupied by longhouse peoples, most of whom fled due to a series of massive government-sponsored punitive expeditions at the end of the nineteenth century. Thus, at least some of the sago exploited by Western Penan today occurs as an artifact of previous agricultural clearance. Though this might be interpreted as a support for Bailey's hypothesis, I do not believe this to be the case. First, most of the sago exploited by Penan Gang occurs in steep areas never previously subjected to clearance. Second, all those areas previously cleared are in relatively flatter areas adjacent to larger rivers such as the Seping, and the sago which occurs there is significantly less robust than that which grows on steeper ridges and slopes. By far the greatest yields are from palms growing in these steeper areas. Third, Penan settlement in proximity to major rivers, where they can take advantage of riparian sago, is a recent phenomenon, having occurred only since pacification in the 1920's.22 It is significant, too, that Eastern Penan molong neither the Eugeissona palm nor any other

2tThough I lack figures, I would estimate that perhaps only about 15-20% of specific Eugeissona clumps occurring in areas occupied by Penan Gang have been molong. However, close to 100% of the Eugeissonia in the area is molong in this second, broader sense of the term.

22Prior to this, Penan preferred to live inconspicuously in higher elevation areas away from larger rivers, where they were less subject to raids.

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resources (Rodney Needham, personal communication). Furthermore, most remaining nomadic Eastern Penan groups live in areas not previously subject to agricultural clearance. Thus, even more than Western Penan, Eastern Penan would seem to counter Bailey's argument.

The other major component of the Penan diet is the meat and fat provided by hunting. The game which Penan prefer over all others is bearded pig (Sus barbatus). This is not only because of the much larger amount of meat they provide, but also because of their high fat content. Many other types of game are eaten, but the bearded pig is considered by far the best. It is also by far the most common type of game procured.

Though Western Penan employ several methods of hunting, the most common method is that of hunting with spears and dogs. The primary game encountered and killed is the bearded pig.24 The overall hunting success rate for hunting with dogs is very high, approximately 85-90%. However, this rate varies throughout the year depending on pig densities. On most hunts at least one pig is usually killed, often two. Pigs killed by Penan vary in weight and fat content. Most weigh between 60 and 120 lb. Furthermore, fat deposits on bearded pigs vary seasonally and yearly. I recorded the fat deposits along the chest and back of pigs over a period of 3 years. Fat measurements varied from 0 to 120 mm. Most of the time, pigs have from 5 to 20 mm of fat and every year, at the end of the fruit season, pigs with 30-40 mm of fat are common. Fat deposits of greater than 60 mm are exceptional, occurring only during years of heavy fruiting. Bailey et al. (1989, p. 61) have noted that "animals in tropical rain forests are unlikely to be adequate substitutes for carbohydrates as sources of calories." While this is almost certainly the case in most rain forest habitats, it definitely does not apply to central Borneo. The fat provided by the bearded pig plays a key role in the diets of virtually all Bornean foragers, accounting for a high percentage of calories consumed.

I have provided here a case of foragers existing in a tropical forest ecosystem without recourse to ag ricultural supplements in areas mostly un- disturbed by previous clearance. Not only this, but they have been able to do so in very large groups, with camps occupied for long periods of

231t is worth noting that in 24 months of field research, not once did I witness Penan consuming items such as snakes, hornbills, or sago grubs. Neither did I ever observe the consumption of wild yams, which are considered by Penan to be vastly inferior to sago.

24Eastern Penan, on the other hand, employ primarily blowpipes in hunting and, as a consequence of seeking both terrestrial and arboreal types of game, procure a greater variety of prey species, though the total yield, both in weight and in fat content, seems to be significantly lower than for Western Penan.

25Bailey (1990, p. 747) remarks, incorrectly, that "no one today ... [lives] in sago palm areas independently of agricultural food sources." Bornean foragers, particularly nomadic Eastern Penan in the Tutoh and Limbang watersheds of Sarawak, are clearly an exception to this.

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time. I have tried to make clear that Penan do not live in a pristine habitat with respect to the effects of past human exploitation on the present abun- dance of resources. Penan actively manage the Eugeissona palm, and their exploitation of this resource has a further impact on the demography of this resource.

This example of Penan foragers living in tropical rain forests may be countered by those who would argue that Borneo is a special case and that the example it provides cannot be generalized to other tropical forest ecosystems. I recognize how unusual the Penan case is. From what we know about other Bornean foragers, and from the descriptions provided by Townsend (1990), Dwyer and Minnegal (1991), and others (see for instance Tan, 1977; Ruddle et al., 1978) it seems more generally that only reproduc- ing sago genera such as Metroxylon and Eugeissona provide exceptions to the rule about the availability of carbohydrates in tropical forests. But I do not think we can simply label these cases as limited exceptions and dismiss them. To do so would be to skirt both the methodological and conceptual issues that these cases raise with respect to the hypotheses of Bailey and Headland. To the extent that these genera appear to respond to conscious or unconscious management by humans, they provide an im- portant challenge to these hypotheses.

CONCLUSIONS

The source of the shortcomings to which I have pointed in the works of Bailey and Headland is in the generality of their hypotheses, particularly in the lack of precision-and indeed in the inconsistency-with which "pure" foraging is defined. How pure should "pure" foragers be, and what are the criteria of purity? I would agree that trade for food should exclude foragers from consideration, but what about the use of iron, or the effects that the exploitation of a resource might have on demographic parameters? Should the fact that such effects are conscious or unconscious be con- sidered? Bailey and Headland must be more explicit about such matters in the statement of future hypotheses, providing explicit criteria and coherent, theoretically-based justifications of those criteria. I am sure that both Bailey and Headland recognize the effects of management on the availability of resources. But whereas I expect that Bailey might consider this as another confirmation of his conclusions, I would consider it a weak- ness of his hypothesis. Again this points to the need for clearer hypothesis definition.

Because of this flaw in their hypotheses, their tests are inadequate and inconclusive. Bailey pursues a strategy of explaining away each case,

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an inconsistent process of elimination. Headland, in examining a particular resource in some detail, provides a more satisfying test of his hypothesis, though still inadequate for the reasons I have specified.

Using contemporary foragers to test these hypotheses, while neces- sary, is not sufficient. They are not a representative sample of foraging in tropical forests and therefore do not constitute a falsification of any hypothesis. The archeological evidence cited by Bailey is less convincing still. The strength of his conclusions, and the results of the test are, there- fore, not conclusive.

Whatever my criticisms, Bailey and Headland have done a valuable service, in the extent to which they have defined the issue of foraging in tropical forests. Whether we agree with them or not, the degree to which their work stimulates research and debate is a positive contribution. My comments should not be taken as a criticism of the procedure they follow as much as a suggestion that it is only a starting point. Indeed I cannot conceive of any better way to initiate a test of their hypotheses than what they themselves have done. The sort of cursory survey they must necessarily have performed is inherently inadequate. In a sense, all of us who work with tropical foragers need to be undertaking an extended test of Bailey's and Headland's hypotheses, or some more adequate variation thereof. It is toward the definition of more adequate hypotheses that I have directed my comments.

ACKNOWLEDGMENTS

The research upon which my discussion of the Penan is based was supported by grants from the National Science Foundation (Grant No. BNS-840762), the Social Science Research Council, the U.S. Department of Education, and the L.S.B. Leakey Foundation. I am grateful to each for making my field research possible. I also wish to thank the Sarawak Museum for their support. Two individuals at the Sarawak Museum are particularly deserving of thanks: Museum Director Lucas Chin and Sarawak Government Ethnologist Peter Kedit. Jayl Langub of the Majlis Adat-Is- tiadat Sarawak was supportive in ways too numerous to mention, and his many keen insights into Penan society have benefitted my work greatly. Many of the points made in this article were refined and clarified in the course of discussions with Bernard J. L. Sellato, and my debt to him is considerable. Finally, Karl Hutterer has shaped my thinking on many of the issues addressed here in numerous discussions over many years. All statements made herein are, however, my own responsibility.

148 Brosius

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