ANT 3514 Introduction to Biological Anthropology

ANT 3514 – Introduction to Biological Anthropology

Lab 3: Primate Behavior and Morphology

Week of 5/23/05

Station 1: Behavioral Observation/ Sampling Methods

We will practice what it is like to take behavioral data on primates. Watch the video for 5 minutes and take ad lib data (see handout) on the monkeys you see.

Now watch the same video and record focal scan data on one of the monkeys in 30 second intervals. Here are some descriptions that may help you: groom self, groom other, receive grooming, visual scan, move, forage, eat, scratch, etc. Use any other words you feel will best describe the activities.

Compare your two data sets. Which do think is a more accurate way of collecting data? In what situation would you need to use ad lib data?

Station 2: Social decision making

What is going on in this picture (A)?

______

Pretend you are an adult male monkey. Why would you spend time doing this to:

a)an infant ______

b)an adult female ______

c)another adult male ______

The marmosets in picture B are participating in food sharing.

Pretend you are an adult female monkey. Why would you spend time doing this to:

a)an infant ______

b)another adult female ______

c)an adult male ______

Station 4: Social Systems

Name the types of social systems pictured here:

Station 5: Ecology

Look at the two different habitats pictured (savanna and tropical wet forest). What behavioral and anatomical traits (listed below) would likely emerge in each of these ecological settings?

a) SAVANNA:

b) TROPICAL WET FOREST:

Traits:

Long-distance vocalizations (for non-visual communication)

Brachiation

Prehensile tail

Large social groups (for predator detection and defense)

Semi-terrestrial locomotion/quadrupedalism

Station 6: Dentition

A. Which set of teeth is human and why?

B. Write down the dental formula for each of the following sets of teeth

C. Answer the following questions using the labeled sets of teeth. There may be more than one correct answer.

Which has bilophodont molars?

Which has a Y-5 cusp pattern?

Which is a New World monkey and why?

Which is a Strepsirhine and why?

Station 7: Identification

Using what you know about primate classification, decide which of these are the following. Give at least one morphological reason for each.

Platyrrhine primates ______

Catarrhine Primates ______

Station 8: Locomotion

Name two skeletal characteristics unique to each of these modes of locomotion:

Leaper

1.______2.______

Arboreal Quadruped

1. ______2. ______

Suspensory Primate

1. ______2. ______

Station 9: Crania

These are an ape skull, a human skull, a monkey skull and a non-primate skull. Describe two differences between:

Ape and human 1. ______2. ______

Monkey and ape 1.______2. ______

Monkey and non-primate 1.______2. ______

Station 10: Sexual Dimorphism

Gorillas exhibit a strong degree of sexual dimorphism. Male gorillas also have a sagittal crest, a ridge of bone running along the top of the skull, which anchors the jaw muscles. Which of these skulls belongs to a female gorilla?

Station 11: Entire skeletons

Here are a human, macaque, and chimpanzee skeletons. Using what you learned about human osteology in Lab 1, fill out the table to describe the differences you see in these bones:

Human / Monkey / Chimp
Scapula
Os Coxa
Lower limb

THOUGHT EXERCISES

1. Group Living

Name 3 reasons a primate would want to live in a group.

Name 3 reasons a primate would NOT want to live in a group.

2. Captive vs. Field Studies

a) Provide an example research question that could best be addressed by studying a primate group in its natural habitat.

b) Provide an example research question that could best be addressed by studying a primate group in captivity

READING QUESTIONS:

1. Why are humans categorized as paraphyletic? (Ch. 16 - Marks)

2. How might the study presented by Strier (Ch. 17) be of practical use to humans?

3. Based on the evidence outlined in Sussman's article (Ch. 20), do you think that violence is an inherent part of the human condition? (This is an opinion question, but provide a thoughtful response that clearly illustrates that you read and understood the article).

4. How does Johanson and Edey (Ch. 1) define hominid? How do they define human?

5. Which parts of the Lucy skeleton are more similar to the chimpanzees? Which are are similar to the human? (Textbook Chapter 10)

6. What was Dettwyler (Ch. 4) hoping to find out by examining the mouths and teeth of her subjects?

Primate Behavior Handout

Sampling Methods and Data Collection

Data on primate (and other animal) behavior are usually collected using established sampling rules and recording rules. Sampling rules tell you which animals to watch and when while recording rules tell you how to record this information (Martin and Bateson 1993). For this lab we will be using ad libitum (ad lib) sampling and instantaneous focal animal sampling.

Ad lib sampling: no specific constraints are put on what is recorded or when. Observers write down anything that seems relevant or interesting at the time. Ad lib sampling is most useful in recording rare events such as copulations or predation that might be missed in focal animal sampling.

Data collected ad lib might look like this:

1020: adult male grooms other adult male.

1114: monkey eats caterpillar.

1205: subject visually scans sky for 30 seconds.

Instantaneous focal animal sampling: This is really made up of two parts – instantaneous sampling and focal animal sampling. Instantaneous sampling is a recording rule that tells you how to record something. Focal animal sampling is a sampling rule that tells you what animal to watch and when.

Focal animal sampling means that one animal is observed for a period of time and its behavior is recorded. Focal animal sampling should be used when you need to know how often something happens. With this method, you can tell how much of their time an animal might spend resting or feeding, as all of their time is accounted for.

Instantaneous sampling means that at designated time intervals the behavior being observed at that instant is recorded. Data collected this way might look like the following:

Start time: 1030 Focal animal: juvenile male

Interval 1: scratch

Interval 2: move

3: move

4: drink out of hole in tree

5: drink

6: rest

7: catch grasshopper

8: eat grasshopper

These are just two examples of many data collection methods.

Social Systems:

These are the most common types of primate social systems:

One-male group: Single adult male living with several adult females and their offspring

Fission-fusion society: large group splits into smaller subgroups, which usually consist of an adult female and her offspring or a group of adult males. The large group will join together again at particular feeding spots.

Monogamous Family: one adult male, one adult female and their offspring.

Multi-male group: Several adult males and females and their offspring

Polyandrous: One reproducing adult female and her offspring plus several sexually active males

Primate Morphology

This lab will give you tools to use in order to morphologically differentiate some types of primates from others. Below are a few things you will need to know in order to do this. You will see examples in lab. Pages 138-152 in your textbook will be useful for this lab.

Dentition

Primates all have heterodont dentition. This means the teeth are not all the same. Primates possess different teeth used for different functions. These teeth are:

Incisor: tooth designed for cutting

Canine: tooth with pointed cusps for tearing and incising

Premolars: teeth with broad occlusal (top) cusps for grinding and reducing food material as an aid to digestion

Molars: same as premolars but with broader occlusal surfaces

In primates, as in all toothed mammals, the dentition of each side of the jaw is a mirror of that on the other side. Therefore it is sufficient to describe only half of the dentition of the upper and lower jaw. However the number of teeth in the upper and lower jaws may differ, so each must be counted. To count dentition, start at the incisors and count around towards the back of the jaw. The teeth are counted like this:

Incisors-canine-premolars-molars

The upper jaw is on top and the lower jaw is on the bottom.

Counting these teeth results in a dental formula. Primates can be identified by their unique dental formula. Primates have lost a premolar and an incisor in comparison with other mammals, so a primate dentition will look like 2133 or 2123

2133 2123

Most other mammals have three incisors per side and four or five premolars.

One special primate feature found in Strepsirhine primates is the dental comb. The dental comb is formed from the procumbent (tilted forward) incisors and canines on the lower jaw. Often, when there is a dental comb, the 1st premolar takes over the function and shape of a canine. It is then referred to as caniniform.

Other features:

It is also useful to look at the cusp pattern of molars. The cusps can have a bilophodont, non- bilophodont, or Y-5 pattern. Bilophodont molars have 4 cusps, arranged in two pairs and are characteristic of Catarrhine monkeys. Y-5 molars have 5 cusps arranged in a y pattern and are characteristic of humans and apes.

You should also know the diastema, a space in the toothrow that accommodates one or more teeth in the opposite jaw when the mouth is closed.

Classification

Primates are classified in different ways. The following tables show some of the classifications, and some of the characters of primates within each.

Strepsirhine

Haplorhine

Rhinarium present / No rhinarium
Frenulem present / No frenulem
Two part mandible / Fused mandible
Postorbital bar / Complete bony eye socket
Long muzzle / Reduced muzzle

The Haplorhine category can further be divided into these two infraorders:

Platyrrhine (New World Monkeys)

Catarrhine (Old World Monkeys)

Widely spaced, round nostrils / Closely spaced, downward pointing nostrils
12 premolars / 8 premolars
All have tails, some prehensile / Not all have tails, none prehensile