The perks of being among the elite may extend beyond spacious mansions and private jets, according to a study of baboons in Kenya. Twenty-seven years of data showed that high-ranking baboons have stronger immune systems than their chronically stressed underlings.
Researchers examined the health records of baboons living in a natural setting. They looked at many factors that might affect their immune systems, such as age, physical condition, stress, reproductive effort, and testosterone levels.
Higher-ranking baboons not only healed faster from injuries, but also were less likely to become sick. This was true even though they had elevated levels of testosterone and stress hormones, which tend to suppress immune systems.
This type of connection between health and rank is not limited to baboons. Previous research in humans has shown that higher social status is linked to better health. In addition, chronic stress associated with low social status—especially when it begins early in life—can harm health.
Increased stress hormones in higher-ranked baboons are related to fighting, gathering food and having sex. Grooming by other baboons—one of the privileges of being on top—helps return their hormone levels to normal.
In lower-ranked males, however, bullying and lack of a sense of control can raise stress hormones for extended periods. This type of long-term elevation can depress their immune systems, and cause illness or impair wound healing.
It’s unclear whether higher social status improves health, or if being healthier helps baboons get ahead. The authors of the study, which was published in the Proceedings of the National Academy of Sciences, write, “It is likely that both forces interact to shape differences in health and immune function.”