Primates Large Social Groups

What are the different types of large groups?

• Multi-male, multi-female groups

• Single male, multi-female groups

• Chimpanzee social organisation

What are the characteristics of multi-male, multi-female groups?

High competition between males for access to females, and competition between females for access to food resources (nutrition)

What is nutrition important for?

Growth and maturation of females, fertility/reproductive success, and survival of offspring

What are the characteristics of single male, multi-female groups?

• High competition between males

• Selection for traits that favour dominant males: body size and strength, canine size

• Increased sexual dimorphism through male-male competition

• Bachelor groups

• Eg. Mountain gorilla (silverback male)

What are the characteristics of chimpanzee social systems?

• Large, complex social groups

• Multi-male polygyny

• Hierarchy in males and females

• 'fission and fusion' social systems

What is a ‘fission and fusion’ social system?

A dynamic structure where a larger social group splits into smaller subgroups (fission) and then merges back together (fusion) as needed, often in response to environmental factors or resource availability