Cultural and physical characteristics of near-Arid savanna chimpanzees in Mali

The absence of encounters between researchers and chimpanzees (Pan troglodytes verus) in Mali is primarily because of their scarcity and evasiveness, the result of being hunted, as well as the extreme climatic conditions. Here we present the first videotaped evidence of wild chimpanzees (possibly a family of three) in the near-Arid cliff ranges of southwest Mali and describe some of their putative cultural attributes and survival strategies based on indirect observations. Regarding their sleeping sites, we identified rock shelters and cliff ledges, as well as a diversity of tree/brush bed-platforms of different heights, shapes, compositions and sizes. Most chimpanzee nests in these cliff ranges were found adjacent to walls and appeared to be reused. Sticks and stones for extractive foraging were discovered at excavation sites, shattered logs atop large stone anvils, and turned-over rocks in brush fire zones. All of these finds were discovered in the vicinity of either chimpanzee hair/feces (in/ under nests), foot/knuckle prints or food remnants. Moreover, we hypothesize that a shortage of resources has driven the evolution of a unique "bamboo culture" in these highly adaptive chimpanzees, manifested in the construction of complex bamboo dome-shaped nest supports, as well as a navigation system containing stationary and mobile components. Furthermore, an unexpected mode of locomotion was observed in three endemic chimpanzees at the National Zoo of Mali, exhibiting a previously thought to be uniquely hominin-Type bipedal gait -An observation awaiting corroboration from the wild.