[Guinea] Chimpanzees in Guinea are regularly using long and robust tools to fish for algae, reveals new research published this month in the American Journal of Primatology.
Chimpanzees (Pan troglodytes) often use tools to extract or consume food but which tools they choose for which purpose can differ depending on where they live.
In 2010, a team of primatologists from the Max Planck Institute for Evolutionary Anthropology initiated the ‘Pan African Programme: The Cultured Chimpanzee’ (PanAf) to characterize and understand the differences in chimpanzee behaviors in poorly studied ape populations across Africa.
This is how they encountered a new behavioral variant: algae fishing with tools at PanAf’s research site in Bakoun, Guinea.
“We present the discovery of a newly observed tool-use behavior in a population of chimpanzees living in the Bakoun Classified Forest, Guinea, where a temporary research site was established for 15 months,” the researchers said.
“Bakoun chimpanzees of every age-sex class were observed to fish for freshwater green algae from rivers, streams, and ponds using long sticks and twigs, ranging from 1.2 inches (9 cm) up to 14.1 feet (4.31 m) in length.”
Using remote camera trap footage from 11 different sites, the team found that algae fishing occurred frequently during the dry season.
“Algae fishing events were concentrated during the dry season, and were frequently observed on parts of the river where the algae had the most suitable conditions to grow,” the authors explained.
“During the hot dry season, algae fishing was at its peak and chimpanzees were observed to revisit sites for many days in a row.”
“The algae were filamentous, benthic freshwater green algae of the genus Spirogyra, of which 400 species exist worldwide. The strands are long and characteristically non-branching, and the algae are colloquially referred to as ‘mermaid’s tresses’ or ‘water silk.”
“Spirogyra grows particularly well in open sunlight and slightly deep, calm freshwater as a charophyte, meaning it grows from the river sediment up into the water.”
Bakoun chimpanzees were observed algae fishing for as little as one 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,” the scientists said.
“We suggest that the algae probably provide an important nutritional benefit to the chimpanzees at Bakoun, especially during the dry season,” said study co-first author Prof. Christophe Boesch, Director of the Primatology Department at the Max Planck Institute for Evolutionary Anthropology.
Further analyses of videos and other data collected by the PanAf project are currently underway. Anyone can participate in watching and annotating the videos using the online citizen science website – www.chimpandsee.org.
Christophe Boesch et al. Chimpanzees routinely fish for algae with tools during the dry season in Bakoun, Guinea. American Journal of Primatology, published online November 3, 2016; doi: 10.1002/ajp.22613
View original article at: Chimps discovered using tools to fish for algae