Camera traps find endangered dryas monkeys. The Endangered dryas monkey is one of Africa's most mysterious primates. They are difficult to find because they live in dense vegetation in secondary forest thickets. Using non-invasive research and no-flash camera traps from 2014 to 2019, scientists have confirmed the occurrence of the dryas monkey at seven locations in the Democratic Republic of the Congo spanning a total area of 3,453 square kilometers, based on opportunistic reports provided by local village residents and park patrols. Source 3m.