Baboons are typically ornery creatures, fighting a lot, fiercely competing amongst eachother, and raiding other groups. A study in the Masai Mara of Kenya however, showed that when the most aggressive males of a particular troop were coincidentally killed off by tuberculosis, the remaining troop members (including new males who arrived later) evolved a more relaxed and pacific culture that persisted even 20 years later with mostly new individuals. Pretty fascinating.

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