Shadows of Forgotten Ancestors

An unambiguous, well-defined dominance hierarchy minimizes violence. There’s plenty of threat, intimidation, and ritual submission, but not much bodily harm. Violence does occur when the rank order is uncertain or is in a state of flux. When young males attempt to establish their place in the hierarchy, or when there’s a struggle at the top for alpha status, then there can be serious injuries, even death by combat. But if you don’t mind constantly subordinating yourself to those of superior rank, dominance hierarchies provide a peaceful and ritualized environment with few surprises. Perhaps this is part of the appeal for those humans drawn to the religious, academic, political, police, and corporate hierarchies, and the military establishment in peacetime. Whatever inconveniences hierarchy may impose are offset by the resulting social stability. The price may be paid in anxiety—anxiety about offending those of higher rank, being perceived as insufficiently deferential, forgetting yourself, committing lèse-majesté.

In maintaining the dominance hierarchy, all conflicts (chiefly ritual or symbolic combat) are between animals who know each other well. But xenophobic intraspecific aggression is different, occurring between animals with no perceived bonds, relationships, or even familiarity. It’s an encounter with strange-smelling aliens, and the circumstance most likely to lead to casualties and deaths.

When an unfamiliar mouse arrives, rats drop what they’re doing and attack it—dominant rats attacking the intruder’s back and frequently mounting it in the process, while subordinate rats attack the intruder’s flanks and rarely mount it. Each in his own way.¹⁰

Among mice living in small groups, those at the top of the hierarchy tend to be most active in scuffling, intimidating, and fighting, in reacting to novelty, and in fathering baby mice. They also have sleeker coats than the subordinate males. But when it comes to fighting mice of another group,¹¹ suddenly democratic forms come into play and the subordinates fight side-by-side with the alphas.*

The simplest geometry of a dominance hierarchy is linear or straight-line. This is what we’ve been describing. The private defers to the corporal, the corporal to the sergeant (and if you look more closely, there are various hyperfine grades of privates, corporals, and sergeants), the sergeant to the second lieutenant, and so on, up through first lieutenant, captain, major, lieutenant colonel, colonel, brigadier general, major general, lieutenant general, plain old general, and general of the army or field marshal. The military establishments of different nations have different names for the various ranks, but the basic idea is the same: Everyone knows his rank. A currency of deference is offered by subordinate to superior. Homage is paid.

Linear hierarchies are a mode of social organization readily observable in domestic fowl, which is where the phrase “pecking order” originates. It’s especially clear-cut among the hens. (In mammals the pecking order is often the chief fact of male social life.) Again, the alpha hen pecks beta and everybody lower; beta pecks gamma and everybody lower; and so on down the hierarchy to poor omega, who has no one at all to peck. The high-ranking males try to sexually monopolize the hens, but sometimes they fail. Cocks dominate hens except on rare occasions; the word “henpecked” refers to the exceptions and comes from everyday observation of barnyard life.

With large populations a linear rank order is rare; instead, little triangular loops break out in which delta dominates epsilon, epsilon dominates zeta, but zeta in addition to dominating eta also dominates delta, or maybe even someone higher up the hierarchy.¹² This leads to a social complexity that may be opposed by die-hard conservative chickens.

How does the dominance hierarchy get established? When two chickens are introduced to each other, there is usually a brief squabble—involving much clucking, squawking, pecking, and feathers flying. Or else one chicken takes a good look at the other and submits without a fight, as is usually the case when an immature chicken is confronted by a healthy adult. Among vigorous hens, the winner is the better fighter, or the better bluffer. A home-court advantage is reported: A hen is more likely to win the fight in her own yard than in her adversary’s. Aggressiveness, bravery, and strength play their roles. After a single instance of dominance combat, the relationship between the two hens is often frozen; the higher-rank has the right to peck the lower-rank without fear of retribution. Flocks in which high-ranking hens are regularly removed and replaced by total strangers fight more, eat less, lose weight, and lay fewer eggs. In the long view, the pecking order is in the interest of the chickens.¹³