Conflict, Compromise, and Cooperation Between the Sexes
Societies develop as a result of the interactions of individuals as they compete and cooperate with one another in the evolutionary struggle to survive and reproduce successfully. Gorilla society is arranged according to these different and sometimes conflicting evolutionary goals of the sexes. In seeking to understand why gorilla society exists as it does, Alexander H. Harcourt and Kelly J. Stewart bring together extensive data on wild gorillas, collected over decades by numerous researchers working in diverse habitats across Africa, to illustrate how the social system of gorillas has evolved and endured.
Gorilla Society introduces recent theories explaining primate societies, describes gorilla life history, ecology, and social systems, and explores both sexes’ evolutionary strategies of survival and reproduction. With a focus on the future, Harcourt and Stewart conclude with suggestions for future research and conservation. An exemplary work of socioecology from two of the world’s best known gorilla biologists, Gorilla Society will be a landmark study on a par with the work of George Schaller—a synthesis of existing research on these remarkable animals and the societies in which they live.
CHAPTER 1 INTRODUCTION
The Book’s Aim
1.1. What Is a Society? What Is Socioecology?
1.2. Why Primate Socioecology?
1.2.2. Primates are relatively well known
1.2.3. Primates are diverse
1.2.4. Primate males and females live together
1.2.5. The study of primates
Structure of the Book
CHAPTER 2 PRIMATE SOCIOECOLOGY: A BRIEF INTRODUCTION
2.1.2. Females to food, males to females
2.2.2. Food and competition
22.214.171.124. The nature of competition affects the nature of the society
126.96.36.199. Food and the benefits of cooperation in competition as a cause of grouping
2.3.3. Predation and grouping
188.8.131.52. Grouping evolved for protection from predation?
184.108.40.206. Grouping with a male for protection from predation
220.127.116.11. Sexual dimorphism and group size
18.104.22.168. Association without active care?
22.214.171.124. Association to mate-guard
126.96.36.199. Association to guard against infanticide
188.8.131.52. More than one male associating
184.108.40.206. Breaking the association—emigration
220.127.116.11. No association—roving males
2.4.4. Female and male responses to mating competition
18.104.22.168. Male responses to female responses
2.5.2. Female competition to rear
PART GORILLAS, ECOLOGY, AND SOCIETY
CHAPTER 3 INTRODUCING GORILLAS: SOME BACKGROUND
3.1. Distribution, Taxonomy, and Study Sites
3.1.2. Taxonomy: How many species?
3.1.3. Study sites
22.214.171.124. Eastern lowland, or Grauer’s gorillas
126.96.36.199. Western gorillas
3.2.2. Body size and sexual dimorphism
3.2.3. Maturation and reproduction
188.8.131.52. Maturity and reproduction in males
184.108.40.206. Maturity and reproduction in females
220.127.116.11. Causes of mortality
3.2.6. Lifetime reproduction
3.2.7. Comparison with Pan and Pongo
Summary: Gorilla Ecology
Introduction: Gorilla Ecology
4.1.2. General habitat and food preferences
4.1.3. Diet, altitude, and season
18.104.22.168. Eastern lowland, or Grauer’s gorillas
22.214.171.124. Mountain gorillas
4.1.5. Diet and home range size
4.1.6. Ecology and group cohesion
4.1.7. Ecology and population density
4.1.8. Comparison with Pan and Pongo
4.2. Gorilla Society
Summary: Gorilla Society
Introduction: Gorilla Society
126.96.36.199. Dispersal; group formation, transition, and demise
188.8.131.52. Interunit encounters
184.108.40.206. Relationships between adult females
220.127.116.11. Relationships between adult males
18.104.22.168. The social relationships of immature animals
PART FEMALE STRATEGIES AND GORILLA SOCIETY
Introduction: Gorillas; Food, Competition, and Cooperation
5.1. Female Strategies: Food, Competition, and Grouping
5.1.2. Is the competition important?
5.1.3. Conclusion: Food, competition, and grouping
5.2.3. Conclusion: Food, cooperation, and emigration
CHAPTER 6 FEMALE STRATEGIES: MALE INFLUENCES ON FEMALES’ COMPETITION, COOPERATION, AND GROUPING
6.1. The Male Is a Major Competitor
6.2. The Male Mitigates Competition Among Females
6.3. The Male Mitigates the Benefits of Females’ Cooperation
6.4. Comparison with Pan and Pongo
CHAPTER 7 FEMALE STRATEGIES: MALE INFLUENCES; JOINING A PROTECTIVE MALE87
7.1. Protection from Predation
Summary: Protection from Predation
7.1.2. Females join males
7.1.3. Gorillas are preyed upon
7.1.4. Males protect females
22.214.171.124. Females (and immature animals) act as if they perceive that the male is a protector against predators
7.2. Protection from Infanticide
Summary: Protection from Infanticide
7.2.2. Female gorillas associate with a powerful male for protection against infanticide by other males
126.96.36.199. Females associate with a male for protection against infanticide
188.8.131.52. Females associate with a male for protection against infanticide: A model
184.108.40.206. The model’s conclusions
220.127.116.11. Criticism of the model
7.3. Conclusion: Predation or Infanticide?
7.3.2. Infanticide is the primary cause of association
7.3.3. The hypotheses cannot yet be separated?
CHAPTER 8 FEMALE STRATEGIES: MALE INFLUENCES; EMIGRATION AND CHOICE OF MALES5
8.1. Female Emigration and Mate Choice: Finding a Better Protector
8.2. Female Emigration and Mate Choice: Avoiding Inbreeding
8.2.2. Incest in gorillas: Inbreeding is not always avoided
8.2.3. Minimal costs to inbreeding?
CHAPTER 9 FEMALE STRATEGIES: CONFLICT, COMPROMISE, AND COOPERATION BETWEEN THE SEXES
9.1. Gorilla Female Society
9.1.2. Protection and society: The male’s influence
9.1.3. Emigration by females: The male’s influence
9.3. Gorilla Society: An Unusual Product from Interaction of Usual Rules
PART MALE STRATEGIES AND GORILLA SOCIETY
CHAPTER 10. MALE STRATEGIES AND SOCIETY: INFLUENCES OF THE ENVIRONMENT AND OF FEMALES
10.1. Association as a Means of Access to Females
10.1.3. Gorillas cannot roam, but must associate permanently
10.3. Comparison with Pan and Pongo
10.3.2. Predation and association
A robust model, and therefore the right answer?
Are female strategies irrelevant to males?
CHAPTER 11. MALE MATING STRATEGIES AND GORILLA SOCIETY
11.1. Competition to Be Sole Breeder
11.1.2. The reproductive payoffs of infanticide
11.1.3. Male competitive tactics: Mate acquisition versus mate retention and offspring protection
18.104.22.168. Why are there no male takeovers? The influence of females on the stability of male-female associations
22.214.171.124. Mating competition and male-female interactions: Coercion and mate-guarding
11.1.6. Long-term reproductive strategies
126.96.36.199. Control of female aggression
11.2.2. Why dominant males tolerate younger rivals?
11.2.3. Staying versus dispersing
11.2.4. Reproductive payoffs of different male strategies
11.2.5. Why leave?
188.8.131.52. Interaction of male and female strategies and the perpetuation of group structure
184.108.40.206. Lower risk of infanticide
220.127.116.11. Familiarity and relatedness between males and females of different groups
CHAPTER 12. MALE STRATEGIES AND THE NATURE OF SOCIETY: CONFLICT, COMPROMISE, AND COOPERATION BETWEEN THE SEXES
12.1. Gorilla Society: The Influence of Females on Males
12.2. Gorilla Society: The Influence of Males on Females
12.3. Gorilla Society: Conflict, Compromise, and Cooperation
12.4. Males and Society: A Familiar Case Study?
12.5. Males and Society: An Unfamiliar Case Study?
PART GORILLA SOCIETY: THE FUTURE
CHAPTER 13. GORILLA AND PRIMATE SOCIOECOLOGY: THE FUTURE
13.1. Gorilla Society Yesterday
13.2. Gorilla Society Today
13.3. Gorilla and Primate Society Tomorrow
13.3.2. Diet, competition, cooperation, and grouping?
18.104.22.168. Some methodology
22.214.171.124. Intergroup aggression and kinship
126.96.36.199. Duration of male tenure
13.3.5. Within-species community structure?
13.3.6. Sexual selection, environment, and society: Predation versus infanticide?
13.3.7. Schemas, quantification, modeling, and experiments?
188.8.131.52. Gorilla socioecology
CHAPTER 14. SOCIOECOLOGY AND GORILLA CONSERVATION
14.1. Conservation’s Five Questions: Why? What? How Much? Where? How?
14.1.2. What to conserve?
184.108.40.206. Some reflections on the Red List
220.127.116.11. Protected areas and tourism?
14.2.2. How can socioecology help?
14.2.3. Socioecology and demography
14.2.4. Socioecology and reaction to the environment
14.2.5. Socioecology of human use of the environment
14.2.6. Socioecology and active management
14.2.7. Socioecology and tourism: The relevance of socioecology
14.2.8. Socioecologists and conservation
14.2.9. Conservation and socioecology