These monkeys have used tools for 700 years

The capuchin monkeys of Brazil’s Serra da Capivara National Park use stone hammers and anvils to crack open cashews — just as their parents did, and their parents’ parents, and so on back for at least 700 years. Theirs one of the oldest known examples of nonhuman tool use; so old, in fact, that researchers studying it wonder whether early humans might have benefited from watching their clever monkey cousins.

The nut-cracking monkeys were first observed by University of São Paulo primatologists Tiago Falótico and Eudardo Ottoni, who noticed that monkeys left their dense quartzite tools beneath the cashew trees. Joined by Oxford University primate archaeologist Michael Haslam, they excavated several such sites, and found layers of tools dating back to the 13th century.

Described in a study published in the journal Current Biology, it’s the oldest evidence of tool use outside chimpanzees and Homo sapiens. “Humans could potentially have learned about the cashew nuts from the monkeys,” says Falótico — which is something we won’t ever know, but is fun to consider, and underscores the sophistication of the monkeys’ culture.

Monkeys don’t simply use tools by instinct. Rather, young monkeys learn the techniques by watching their elders. The excavated tools from Serra da Capivara represent more than 100 generations of tradition. And cracking cashews isn’t the only local tradition: recently Falótico found that females in one particular group have learned to get the attention of males by throwing stones at them.

Though monkey culture receives less scientific attention than chimpanzee culture, that may soon change. “We’re beginning to understand that wild capuchins have more diverse and complex and complex tool use behavior than first thought,” says Falótico. “This behavior is in many ways comparable to chimpanzees.”

How many other monkey cultures might there be? A great many, perhaps, and it’s all the more reason to think of conservation not merely in terms of species or subspecies, but local populations and communities.“If a particular group has a cultural variation and this group ceases to exist, then we simply lose all the information that was maintained for generations,” says Falótico. People might reintroduce the species, but it won’t be the same. —Brandon Keim | 13 July 2016

Source: Haslam et al., “Pre-Columbian monkey tools.” Current Biology, 2016. DOI: 10.1016/j.cub.2016.05.046

Image: ©Michael Haslam/Primate Archaeology Project