Research topic and methodology overview

¶ … Dim Forest, Bright Chimps" by Christophe Boesch & Hedige Boesche-Achermann is a somewhat anecdotal review of the authors' experiences studying chimpanzees that inhabit the rainforest of the Ivory Coast. After an initial recount of an after-the-hunt scene, Boesch & Boesche-Achermann describe the chimpanzee troupe's tool usage, and other behaviors -- such as hunting and social interaction -- often comparing them with Jane Goodall's chimps in Gombe. Written from an evolutionary perspective, the writers ultimately speculate on how their chimps' behavior relates to the evolutionary process of the first humans.

Boesch & Boesche-Achermann's article opens mid-scene: a group of chimpanzees noisily rush through the rainforest's undergrowth, meeting and clustering around Brutus, a dominant male, who's clutching a barely-alive, shocked red coleus monkey. Brutus appears to savor the moment, standing silently, then confidently "swaggering" through the group with his favorite females and males close behind. The authors then transition by using the anecdote to introduce the nature of their long-term study: to research chimps' cooperation during hunts, tool use, and later, to compare and contrast their chimps' behaviors with those of their savannah counterparts. All this, the authors say, in hopes that new light be shed on prevailing theories of human evolution. In this vein, of specific interest was their chimps' cooperative behavior during hunting; it is this same behavior many anthropologists hold played a crucial role in social system development of early hominids, some 1.8 million years ago.

The article goes on to report -- within a kind of narrative regarding their subjective experiences studying the chimps -- the authors' most significant findings. First, Boesch & Boesche-Achermann found their chimps were capable of remembering the locations of out-of-sight stones around a panda tree. The chimps could quickly select one of appropriate size and use it to crack open nuts, one of their favorite foods. This ability in spatial representation, Boesch & Boesche-Achermann report, generally compares with that of nine-year-old humans. Second, our authors found their chimps could carry out a fairly organized hunt; traps would be set for monkeys, where one chimp frightened a group of monkeys, causing them to take off in the direction of three other chimps, all blocking possible escape routes. Boesch & Boesche-Achermann found that this organization was key to a hunt's success -- when three or four chimps hunted, there was a success ratio of more than half. The chimps knew it, too; 92% of all the hunts the researchers observed were carried out in groups. Of those that were done in groups, 63% had some level of coordination. This statistic differs greatly from Jane Goodall's chimps at Gombe, who coordinated only 7% of their hunts. Boesch & Boesche-Achermann suggest that this contrast is of value to our understanding of human evolution; when a dramatic climate change struck Africa, east of the Rift Valley, it caused our ancestors to -- in adaptation to these new conditions -- develop cooperation in hunting. However, in Boesch & Boesche-Achermann's rainforest-dwelling chimps, we also see a high level of cooperation. Thus, we may need to rethink the timeline and setting of human evolution. Similarly, Boesch & Boesche-Achermann's chimps' hunting and tool use was more complex than Goodall's chimps,' and food sharing -- an behavior thought to be unique to humans -- occurs much more frequently in Boesch & Boesche-Achermann's chimps than in the chimps in Gombe.