Unit 3
Ranging Patterns and Social Organization

In this unit, we examine the different types of grouping patterns found among primates, and discuss how the environment influences the size and composition of primate groups. We also examine how diet and resource distribution affect the type of group that primates will form, and how competition for scarce resources can affect group size and the relationships among group members. First, however, we review some important concepts related to ranging patterns (how individuals or groups move in the environment to find resources), and consider under what circumstances it is possible to defend a particular area from other individuals or groups. Because most primates live in permanent associations with other individuals, we also examine the advantages and disadvantages of forming such groups.

Objectives

When you have completed Unit 3, you should be able to

1. define the concepts home range, day range, core area, and territory, and explain how each of these zones is measured in the field.
2. discuss the various social and ecological factors that affect primate ranging patterns.
3. discuss how mode of locomotion is related to home range and day range.
4. explain the difference between social groups, breeding groups, and foraging groups.
5. explain the factors that affect group size and group structure.
6. describe the five different breeding group structures found among primates.
7. explain the relationship between resource distribution and group structure.
8. explain the major advantages and disadvantages of living in a group.

Viewing Assignment

If you wish to complete your next viewing assignment now, you may choose either Spirits of the Forest, described in Unit 2, or the video listed below.

Zeller, Anne

1997 Images from the Field: Baboons. Watertown, MA: Documentary Educational Resources.

This video provides a closer look at the olive baboons, describing, among other things, typical behaviours of a group, sociosexual behaviour, dominance interactions, and interactions with human populations.

If you choose this video, then in preparation for the examination, be certain that you can answer the questions given below.

1. What roles do males play in the group?
2. What is a typical day for a baboon troop?
3. Why do human populations hunt baboons?
4. What functions does presenting have among baboons?

Note: Once you have completed the viewing assignment to your satisfaction, please return the video to the Athabasca University Library as soon as possible: the number of copies is limited, and other students will need it. Remember, too, to submit your request for the video for your next viewing assignment—see pages 46-47 in Unit 4 of the Study Guide.