Life at the Top: Rank and Stress in Wild Male Baboons

Abstract

In social hierarchies, dominant individuals experience reproductive and health benefits, but the costs of social dominance remain a topic of debate. Prevailing hypotheses predict that higher-ranking males experience higher testosterone and glucocorticoid (stress hormone) levels than lower-ranking males when hierarchies are unstable but not otherwise. In this long-term study of rank-related stress in a natural population of savannah baboons (Papio cynocephalus), high-ranking males had higher testosterone and lower glucocorticoid levels than other males, regardless of hierarchy stability. The singular exception was the highest-ranking (alpha) males, who exhibited both high testosterone and high glucocorticoid levels. In particular, alpha males exhibited much higher stress hormone levels than second-ranking (beta) males, suggesting that being at the very top may be more costly than previously thought.

Social status predicts wound healing in wild baboons

“…Once they obtain high rank, males experience several costs that could limit immune function. For instance, high-ranking males are more likely to engage in energetically expensive mateguarding episodes (45,46). These mate-guarding episodes, called "consortships," may last from a few hours to a few days, during which time male foraging is compromised; indeed, consorting males have feeding bouts that are 10-15% shorter than those of nonconsorting males, and it is not uncommon for males to abandon consortships (46,47).…”

“…These mate-guarding episodes, called "consortships," may last from a few hours to a few days, during which time male foraging is compromised; indeed, consorting males have feeding bouts that are 10-15% shorter than those of nonconsorting males, and it is not uncommon for males to abandon consortships (46,47). In addition, in Amboseli, high-ranking males have higher fecal testosterone levels than low-ranking males (45), both when the dominance hierarchy is unstable and when it is stable (45). Furthermore, alpha males (the highest-ranked male in each group) experience higher costs than other high-ranking (but nonalpha) males, including high testosterone, higher rates of conflict than beta males, and the most time spent in consortships (45).…”

“…Male baboons are a good system for understanding the relationships between dominance rank and immune function because high male rank usually leads to high reproductive success (40,41) and because we already know a good deal about the behavioral and physiological correlates of dominance rank in baboons (41)(42)(43)(44)(45). Baboons live in multimale, multifemale social groups characterized by linear dominance hierarchies.…”

Importance of a sense of control and the physiological benefits of leadership

“…Finally, a recent study of a population of wild baboons showed something particularly subtle (11). Amid the 10-20 males in each of the five troops monitored, there was a linear relationship, such that the higher the rank, the lower were the cortisol levels.…”

Not the Last Word: Orthopaedic Surgery Is Lucrative (But Evidently Not Lucrative Enough)

“…Granted, the cuts in fees have affected all specialties, but an equal percentage cut has the greatest net effect on those collecting the most; moreover, the threat of future cuts may be most stressful for those at the top of the income scale [8].…”