Unit 5
Food, Sex, and Social Organization

A basic life problem confronted by all living organisms is deciding what to eat in order to maximize energy intake while minimizing energetic output. Given body size and reproductive energetic requirements and turnover rates of different species, what kinds of foods would we predict species to utilize? What is in food, and what should species look for? What should they avoid? This unit will explore the basic aspects of food quality and distribution, and how these correlate with primate behaviour in terms of ranging and grouping patterns, reproductive seasonality and competitive regimes within and between groups.

Objectives

When you have completed Unit 5, you should be able to

1. explain why ecological constraints (like food quality, seasonality, and distribution) exert more selective pressures on females than males.
2. describe all the basic components of high- and low-quality diets, and the types of foods in which these components are found.
3. describe some of the morphological adaptations to diet found in primates that specialize in certain types of foods.
4. describe the components found in some foods that should be avoided, and how some primates have adapted by not avoiding them.
5. discuss the effects of the spatial and temporal (seasonal) distribution of different food types on various behavioural correlates, such as ranging patterns, group size and social organization, competition, and activity budgets.
6. explain the effects of diet on reproductive seasonality, and how this relates back to mating patterns and social behaviour.
7. discuss the dietary variability of the colobines in light of recent ecological studies.

Viewing Assignments

In preparation for the first examination, you must watch at least three videos listed in Units 1 through 5. Each unit gives you two video options, so that by the end of Unit 5 you should have watched three videos from these four options:

Five Species or Primate Patterns II
Lemurs of Madagascar or Spirits of the Forest
Darwin’s Revolution in Thought or Great Transformations
Images from the Field or Baboon Tales

It does not matter the order in which you watch your video options, but the viewing assignments for each unit offer you a guide. Remember, completing a viewing assignment differs from watching a video for pleasure. You should consider watching each video twice: once to get an overview, and once to make notes. Study questions or instructions for viewing are supplied for each video; be certain that you read them over before you begin watching, and keep them in mind as you complete the assignment and make your notes.

Unit 5 Viewing Assignment

If you need to catch up on a viewing assignment so that you have watched at least three videos from the four options for the midterm, then do so now. Note that you must have completed three viewing assignments or three alternative reading assignments (or a combination of viewing and alternative reading assignments equaling three) before you take the midterm examination.

Alternative Reading Assignment

If you cannot complete the viewing assignment before the midterm examination, you must do the alternative reading assignment instead. You may combine the reading with viewing assignments so that you have a total of three video and reading combinations. For example, you can watch two videos and do one reading assignment for the midterm. Or, if you cannot watch any videos, then you must complete three reading assignments from the four options presented in Units 1-5. The reading materials can be ordered from the library. Be sure you can answer the questions below each assignment.

Unit 5 Alternative Reading Assignment

If you cannot complete the viewing assignment, you must do the alternative assignment below.

Jansen, Charles
1998  Chapter Twenty-two, Capuchin Counterpoint. In The
Primate Anthology: Essays on Primate Behavior, Ecology
and Conservation from Natural History. Ciochon, R. L., and
R. A. Nisbett, eds. Pp. 153-160. Upper Saddle River, NJ:
Prentice-Hall.

In preparation for the examination, be sure that you can answer the questions below.

1. What are the two species of monkeys discussed in this chapter?
2. Which capuchin species typically forms larger groups?
3. What are the three main social differences between the two capuchin species the author was interested in exploring?
4. What was the main difference in feeding behaviour (and, by extension, food patch size) that might explain some of these social differences between species?
5. What is the main difference in the mating behaviour of brown capuchins that explains why males tolerate juveniles?
6. How does this difference also explain why brown capuchin males must defend fruiting trees without the cooperation of other group males?
7. The author concludes his article by comparing brown capuchin populations in contrasting ecological conditions to test the hypothesis that females actively pursue males that can monopolize food items. Was this hypothesis supported by his observations? What condition seems necessary for consistent female mate preference to exist?