Dense Wild Yam Patches Established by Hunter-Gatherer Camps: Beyond the Wild Yam Question, Toward the Historical Ecology of Rainforests

Prior to the 1980s, most researchers believed that the African forest hunter-gatherers, or Pygmies, were the original inhabitants of the central African rainforests. It was assumed that their close social, economic, and ecological relationships with neighboring agricultural societies did not date back long, and that they had previously lived solely through foraging wild forest products. The same is true for forest hunter-gatherers on other continents. However, Headland (1987) and Bailey et al. (1989) noted that no previous studies had produced sound evidence that pure hunter-gatherer subsistence was possible in any rainforests worldwide, and they argued that it was not, and had never been, possible to live in such areas while solely depending on wild products. Although rainforests contain vast numbers of species and huge biomass, consumable resources for humans, especially sources of calories, seem to be scarce and dispersed. Therefore, they argue, hunter-gatherers adapted to live in rainforests only after they began obtaining agricultural crops from cultivators. This hypothesis was called the “wild yam question” by Headland (1987) because the availability of wild yams was considered to be the key factor that determined whether pure hunter-gatherer subsistence in rainforests was viable. Two opposing arguments have arisen from studies in different regions of the Congo Basin. Hart and Hart (1986) concluded that it was extremely difficult for the Mbuti in the Ituri forest in the eastern Congo Basin to live without agricultural crops, particularly in the dry season and the early rainy season when wild nuts and honey were not available. On the other hand, Bahuchet et al. (1991), Hladik and Dounias (1993), and Sato (2001, 2006) argued that for the Aka and Baka in the western Congo Basin enough wild yams existed for their subsistence. These studies were principally based on investigations of the density of wild yams, and lacked detailed descriptions of the use of wild yams. Therefore, the issue of whether exploitation of wild yams, including searching for them, digging them up, transporting them to the camp, and cooking and consuming them, could have been practiced in everyday life remains inconclusive (cf. Bailey and Headland 1991). Archaeological studies have provided powerful evidence indicating the existence of humans in the African rainforests before the beginning of agriculture (Mercader 2003a, b; Mercader and Martí 2003). Unfortunately, they did not identify the foods upon which the ancient forest huntergatherers depended. They referred to ecological and anthropological studies that suggested ancient hunter-gatherers would have eaten wild nuts and meat, both of which were considered to have limited availability (Hart and Hart 1986). The simplest and most explicit way to demonstrate if and how hunter-gatherers can live on a diet consistingmostly of wild yams is to actually observe it. During fieldworkwith the Baka in southeastern Cameroon, I (2006a; 2009a) recorded all of the harvests during long-term and large-scale hunting-and-gathering camps (molongo in the Baka language) in the dry and early rainy season, i.e., the period during which the forest was thought to be barren (Hart andHart 1986), and found that the forest provided a plentiful food supply, 65 % of which (on a calorie basis) was made up of wild yams, and in particular annual species. Furthermore, Sato et al. (2012) undertook controlled huntingand-gathering camping with Baka informants and demonstrated that annual yams are a staple food throughout the year. However, the question remains as to how yams have become so densely distributed in this area. I (2009a) noted that, within the area containing numerous yam patches, small settlements had been created before the colonial period. Moreover, the forests of Cameroon have been considerably H. Yasuoka Centre d’Ecologie Fonctionnelle et Evolutive, CNRS UMR5175, Montpellier 34293, France