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Chimpanzees (Pan troglogytes) spontaneously use tools to dig underground food

Chimpanzees (Pan troglodytes) spontaneously use tools to dig underground food. Alba Motes-Rodrigo of the University of Tübingen in Germany and colleagues reported findings in PLOS ONE where chimpanzees in captivity know how to use tools to dig underground food, in fact they have never tapped underground food before.

Recent studies have shown that wild chimpanzees and bearded capuchins are able to use tools to dig underground food such as plant roots and tubers, reversing the previous hypothesis that this type of use of tools is unique to humans and ancestors of ancient hominins.

Dlium Chimpanzees (Pan troglogytes) spontaneously use tools to dig underground food

Motes-Rodrigo and colleagues monitored ten P. troglodytes colonies in Kristiansand Zoo in Norway, eight of which were born in captivity and never carried out excavating behavior. The researchers dug five small holes and placed whole fruit and provided wooden sticks. In the second experiment, they did not provide tools that were ready to use for excavation.

Nine out of ten chimps dig fruit buried with eight chimpanzees choosing to use tools rather than bare hands to do so. When chimpanzees are not given ready tools, they collect their own tools from plants. Researchers at least observed six different types of excavation behavior, chimpanzees took turns digging holes, and even sharing fruit.

The authors caution that results from captive chimps may not be exactly extrapolated to wild populations; and that modern apes should not be treated simply as "living fossil" stand-ins for hominin ancestors. Nonetheless, they speculate that early hominins may have worked out how to use simple tools to harvest underground food in a similar fashion to these chimps.

Journal : Alba Motes-Rodrigo et al. Chimpanzee extractive foraging with excavating tools: Experimental modeling of the origins of human technology, PLOS ONE, May 15, 2019, DOI:10.1371/journal.pone.0215644



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