Chimpanzees Wear Masks to Thieve & Pillage! Locals in the riverside town of Mavoko were left stunned this week after a small group of chimpanzees began crafting makeshift masks from layered leaves and dried mud before sneaking into open-air markets. Witnesses say the chimps carefully pressed wet clay onto broad banana leaves, letting it harden into crude face coverings that obscured their features. Once “disguised,” they slipped between stalls, grabbing fruit, bottled drinks, and even a vendor’s