Chimpanzees routinely fish for algae with tools during the dry season in Bakoun, Guinea.
Wild chimpanzees regularly use tools, made from sticks, leaves, or stone, to find flexible solutions to the ecological challenges of their environment. Nevertheless, some studies suggest strong limitations in the tool-using capabilities of chimpanzees. In this context, we present the discovery of a newly observed tool-use behavior in a population of chimpanzees (Pan troglodytes verus) living in the Bakoun Classified Forest, Guinea, where a temporary research site was established for 15 months. Bakoun chimpanzees of every age-sex class were observed to fish for freshwater green algae, Spirogrya sp., from rivers, streams, and ponds using long sticks and twigs, ranging from 9 cm up to 4.31 m in length. Using remote camera trap footage from 11 different algae fishing sites within an 85-km2study area, we found that algae fishing occurred frequently during the dry season and was non-existent during the rainy season. Chimpanzees were observed algae fishing for as little as 1 min to just over an hour, with an average duration of 9.09 min. We estimate that 364 g of Spirogyra algae could be retrieved in this time, based on human trials in the field. Only one other chimpanzee population living in Bossou, Guinea, has been described to customarily scoop algae from the surface of the water using primarily herbaceous tools. Here, we describe the new behavior found at Bakoun and compare it to the algae scooping observed in Bossou chimpanzees and the occasional variant reported in Odzala, Republic of the Congo. As these algae are reported to be high in protein, carbohydrates, and minerals, we hypothesize that chimpanzees are obtaining a nutritional benefit from this seasonally available resource.
Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.|Wild Chimpanzee Foundation, Conakry, Guinea.
Christophe
C
Boesch
Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.
Ammie K
AK
Kalan
Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.
Anthony
A
Agbor
Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.
Mimi
M
Arandjelovic
Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.
Paula
P
Dieguez
Wild Chimpanzee Foundation, Conakry, Guinea.
Vincent
V
Lapeyre
Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.|German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany.
Hjalmar S
HS
Kühl
D000818:Animals; D003223:Congo; D005247:Feeding Behavior; D016701:Guinea; D058086:Microalgae; D002679:Pan troglodytes; D012621:Seasons; D053001:Tool Use Behavior
Pan troglodytes; Papio papio; aquatic foraging; chimpanzee behavior; tool use