Seemingly peaceful gorillas join 'mobs' and beat up rivals: A surprising series of observations of mountain gorillas in Africa's Virunga Mountains has overturned the view that gorillas, like bonobos, rarely turn violent.

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Seemingly peaceful gorillas join 'mobs' and beat up rivals: A surprising series of observations of mountain gorillas in Africa's Virunga Mountains has overturned the view that gorillas, like bonobos, rarely turn violent.