Are Rhesus Monkeys Shows How The Chronic Stress Of Life Of One With A Low Social Status?
This study done using rhesus monkeys shows how the chronic stress of life of one with a low social status can change the immune system even when other risk factors are absent. 45 adult female rhesus macaques were studied. This species was studied because it is a species that is close to humans and naturally forms stable, linear social hierarchies. The researchers made certain that all the animals had access to as much food as needed, and veterinarians regularly checked that they were not sick or injured, to control for these variables.
The researchers arranged the monkeys into groups of five, adding monkeys that had never met each other one at a time into new social groups once a hierarchy was already established. This resulted in the oldest member dominating and the newest member having the lowest rank. There was a total of nine monkeys in each group. Then they monitored how the monkeys treated and interacted with each other, who did the bullying and who cowered. These groups were maintained for a year. During the year, the researchers noted behaviors and obtained blood samples to evaluate changes in cellular and gene activity associated with the monkeys’ social status. Immune cells were obtained from the monkeys and the activity of approximately 9,000 genes were measured. Over 1,600 of them were expressed differently in lower-ranking females than in higher-ranking females especially within natural killer cells which is the first line of defense against…