White-faced capuchin monkeys in Panama’s Coiba National Park habitually use hammer-and-anvil stones to break hermit crab shells, snail shells, coconuts and other food items, according to visiting scientists at the Smithsonian Tropical Research Institute (STRI). This is the first report of habitual stone-tool use by Cebus monkeys.
“Despite being studied for more than 25 years at several field sites, no species in the genus Cebus has ever been previously observed habitually using stone tools,” said lead author Brendan Barrett, formerly a short-term fellow at STRI, and now a postdoctoral researcher at the Max Planck Institute for Ornithology and the Max Planck Institute for Evolutionary Anthropology.
To observe white-faced capuchin monkeys (Cebus capucinus), Barrett and colleagues set up motion sensor-triggered camera traps. Based on a year of data from the cameras, researchers never saw adult females using stone tools, despite their presence at the site. Among males, stone-tool use was common. At one site, capuchin monkeys used tools on more than 80 percent of the days they were observed.