Vigilance Behaviour

Question 1

What type of behaviour usually shows vigilance?

Answer 1

Raising heads to above shoulder height

Question 2

Can animals be vigilant while feeding?

Answer 2

• Yes
• Different animals have different fields of view, depending on their placement of eyes.

Question 3

Give an example of a species that have a wide field of view to enable them to be vigilant when feeding.

Answer 3

Horses
~320°

Question 4

What is the visual streak in animals?

Answer 4

A horizontal area in the retina with many receptors to give max acuity in flat grasslands.

Question 5

What 3 factors tend to increase vigilance?

Answer 5

• When animals are at a distance from other animals or from cover
• In a predator-rich environment
• In mothers with defenceless offspring

Question 6

What 4 other ways is vigilance affected?

Answer 6

• Presence of sentinels
• Age & experience
• Time of day & season
• Level of starvation (motivation)

Question 7

What is the main disadvantage of vigilance?

Answer 7

Uses time that could be spent on other behaviours, e.g. foraging

Question 8

What is the advantage of vigilance in groups?

Answer 8

Improved predator detection

Question 9

What is the dilution effect?

Answer 9

When the risk to an individual is less so they don’t have to be as vigilant

Question 10

Give an example of when group vigilance is seen to be effective.

Answer 10

• In pigeon flocks
• Larger groups = less successful attack rate

Question 11

Why would individuals in the centre of a group not be as vigilant as others? (4 points).

Answer 11

• Feeding competition is greater.
• Further from cover which could hide a predator.
• They can monitor their neighbours.
• Can’t see surroundings well.

Question 12

What is the selfish herd effect theory?

Answer 12

States that individuals within a population attempt to reduce their predation risk by putting other conspecifics between themselves and predators.

Question 13

What is the cost of group protection?

Answer 13

Competition for food; those on the edge can go hungry

Question 14

Give an example of a species that demonstrate the selfish herd theory.

Answer 14

• Adélie penguins
• Individuals need to decide when to enter water when predators are present.
• They need to enter when most others do and the dilution effect is optimum.

Question 15

Is selfish herding beneficial for a group? Give an example.

Answer 15

• If the bunched prey are more obvious then no.
• Whirligig beetles, larger groups are more attractive to predators.
• However, in larger groups the predation rate per individual is less

Question 16

What are another 3 main reasons for vigilance other than predator detection?

Answer 16

1. Males can scan for potential mates or competing males.
2. Vigilance of food sources for potential competition.
3. Predators scan for prey.