A chimp named Juma stuck grass in his ear. Within a week, his whole group was doing it. Then he put grass in his rectum. They copied that too. What this tells us about the origins of culture is genuinely unsettling. #Primatology #HumanEvolution #AnimalCulture https://www.primatology.net/p/grass-in-the-ear-grass-in-the-rectum