While eating dinner this evening I decided to do something I rarely do. I turned on the television. I caught the end a National Geographic program about stress, its causes, and how some baboon studies were giving some insights into how stress affects health.
One interesting event was described where a certain troop of baboons experienced a mass death in the early 80s. The baboons had been foraging in a garbage dump for food and ate some meat tainted with tuberculosis. The majority of the baboons that died were those that were considered "alpha males". They were the most aggressive and dominant of the troop. As the researcher put it, the remaining male baboons left alive were "nice guys". This dramatically changed the social behaviors in this particular baboon troop - less time fighting and more time was spent grooming. As a result, the baboons had reduced stress levels (as shown by medical tests) vs. baboon in other troops.
Even more interesting, this change in baboon culture has been preserved for 20 years. Adolescent male baboons normally leave their troop and find a new troop to call their home. When a new adolescent baboon arrived in this troop, it displayed the usual "jerky male" behavior of a normal baboon, but after about 6 months, the baboon some how learned that the jerky behavior was not acceptable in this troop and he became more passive.
It's a very interesting study. You can read more about it here: http://www.primates.co.uk/baboons/culture.html