APES

There was a PBS program about a scientist who had been observing these apes for years.  At some point there was a tragic disease that almost wiped out this particular tribe of apes - including ALL alpha males apes currently in that tribe.   20 years later the surviving apes' tribe had created their own social order where there were NO alpha males.  Any alpha male from other tribes that came in to this tribe were either repelled or converted to their social order.  The new tribe existed without conflict, living longer than other tribes.