Social Dominance
Dominance Hierarchy
de Waal (1986) contends that the male hierarchy is much more pronounced
than in females, and that males have coalition strategies. Female chimps
are noticeably less social than males. Females are solitary and lack the
social mechanisms that allow tension control and must avoid conflict with
each other. Dominance is determined by conflicts, grooming, and trading behavior,
involving much more than a single agonistic encounter.
Richard & Schulman (1982) suggest that a hierarchy minimizes the risk
of fighting, allowing subordinates to avoid injury and dominant individual
to avoid killing their relatives. The highest rank is achieved in middle
age because physical deterioration lowers the rank of the aged. The male
hierarchy implies no selective advantage for those with high rank, but suggests
benefits from the stability a dominance hierarchy gives. The competition
for food and females is not affected by dominance, but the need to defend
the territory favors males that attack other males. A high social rank can
increase a male’s fitness by allowing more access to meat and mating
(Richard & Schulman, 1982).
Males groom in order to reduce tension and relax the atmosphere making it possible for multiple males to share a female in estrous. Distress vocalizations are reduced through body contact and grooming (de Waal, 1986). Freeland suggests that all social interactions result from disease-avoidance and that territoriality and social stability not only protect food sources but prevent contamination (Freeland, 1976).
Intragroup aggression
de Waal (1986) explains that integration into a community consists of attraction,
aggression, subordination to a senior member, and finally, reconciliation
and social acceptance. Males from the same community are rivals, even known
to kill each other in captivity, and yet also friends. Contests between males
usually last two to three months and the winner avoids reconciliation until
the loser submissively grunts. An example from the wild involves a chimp
named “Evered” who walked for five minutes, and then waited for
twenty-five, until dominant “Figan” awoke, just to make submissive
pant-grunts and bobbing gestures. Aggression and subsequent reassurance contribute
to bond formation.
The distinction between agonistic and ritualized dominance is very pronounced because chimpanzees do not communicate rank by agonistic means, but by grunting, bowing, and moving an arm over the other. Males are forced to cope with competition because they travel in bands and must have close ranks when facing violence from other territories. Females are more likely to be attacked by males than by other females and may avoid the male sphere altogether. However, as males rise in dominance, they provoke females less, and correspondingly, females counter-attack less often against alpha males (de Waal, 1986).
Alpha male
Males groom in order to reduce tension and relax the atmosphere so they
can share females in estrous. In fact, high density leads to more grooming
and also aggression than under normal circumstances due to greater tension.
The highest grooming rate is among the highest ranking males, sometimes referred
to as the triumvirate (de Waal, 1986). The alpha male uses meat as a political
tool to reinforce alliances. About 30% of all meat is stolen by the alpha
male. Males may give meat to swollen females in exchange for sex, and likewise,
females have higher reproductive success upon receiving meat (Stanford, 1996).
Along the same lines, the female bows and grunts to take leaves from the
alpha male (de Waal, 1986).