Observation of tool use and modification for apparent hygiene purposes in a mandrill

Tool making or modification to produce a tool of apparent improved functionality has rarely been reported in monkeys, especially when tools are used outside the context of food acquisition. We report on an observation of selection, modification and use of splinters for hygiene purposes in a male mandrill. The zoo-housed animal was video-recorded breaking splinters in sequence to use them underneath his toenails. This record brings forward new evidence that the ability to use and modify tools is not limited to apes and some New World monkeys but is also apparent in Old Word monkeys.