When one chimpanzee starts putting a blade of grass in her ear, it's an oddity. When a whole bunch of them copy the behavior, it's enough to make scientists go "hmm." The behavior in question first turned up at Chimfunshi Wildlife Orphanage, in Zambia. In 2010, a rescued chimpanzee named Julie started walking around with a long-stemmed blade of grass sticking out of her ear. Over the next year, seven more chimpanzees in Julie's 12-member group began mimicking the behavior.
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