Predation

Question 1

What are the benefits of grouping?

Answer 1

1) Safety (from predators)
2) Food (defending food patches)
3) Raising offspring

Question 2

What are the disadvantages of grouping?

Answer 2

1) Increased visibility
2) Competition (e.g., reduced feeding efficiency)
3) Disease

Question 3

Why is predation difficult to study?

Answer 3

1) Rare event
2) Focus on prey not predator therefore predators are not normally habituated

Question 4

What is dilution?

Answer 4

Selfish herd effect where the chances of being ambushed is less likely when in a group - particularly lowest in the center of a group

Question 5

What are the benefits of group living in terms of predation?

Answer 5

1) Dilution
2) Vigilance
3) Active defense

Question 6

What is vigilance?

Answer 6

Grouping is beneficial in that individuals of a group can spend less time being vigilant without affecting the probability of detecting a predator

Question 7

Why is vigilance sometimes costly?

Answer 7

Time spent looking out for predators means less time spent on other activities (such as searching for food)

Question 8

What is semantic communication?

Answer 8

Acoustically different alarm calls in the presence of different predators - response to each alarm call is therefore different

Question 9

What are primates more weary of in terms of predators?

Answer 9

Primates tend to be more concerned with the presence of a leopard (than for example a chimpanzee, which feeds on red colobus monkeys)

Question 10

How does a predator respond to detection (i.e., alarm calls made by primates)

Answer 10

They are less likely to stay at the site due to loss of element of surprise

Question 11

What is the relationship between group size and sematic communication?

Answer 11

The larger the group size = the more probable the alarm calls (detection of predators)

Question 12

What is active defense?

Answer 12

Attacking in a large group (mobbing) can deter a large predator

Question 13

What are the characteristics of active defense?

Answer 13

1) Can promote cooperation between non-kin
2) Individuals are taking risks
3) Does not always work = lead to predation

Question 14

What are the 2 types of groupings?

Answer 14

1) Number of males per group
2) Polyspecific association

Question 15

How does predation risk alter M:F ratios?

Answer 15

Males help in vigilance and defense, therefore the M:F ratio tends to be higher in high-risk environments

Question 16

What is an example of high M:F ratios in response to predation?

Answer 16

There is less predation by chimpanzees when more male red colobus defenders are present

Question 17

What is polyspecific associations?

Answer 17

When 2 different species come together and associate with each other for hours to days

Question 18

What is the purpose of polyspecific associations?

Answer 18

To reduce predation risk

Question 19

Which are 2 pairs of primates that come together to reduce predation risk?

Answer 19

1) Red colobus/Diana monkeys
2) Ring-tailed lemurs/Verreaux’s sifaka

Question 20

What are the patterns seen when Red colobus/Diana monkeys associate with each other?

Answer 20

When Diana monkeys are present:
1) Colobus monkeys move to lower forest strata
2) Colobus monkeys feed on the ground more
3) Colobus monkeys look down less