Week 4

Question 1

What is the difference between risk averse and risk prone?

Answer 1

averse = sticks to reliable sites
prone = ventures out to variable sites

Question 2

What does the marginal value theorem assume?

Answer 2

as quality of patch decreases or travel time increases, the amount of time spent in a given path will be longer

Question 3

What are two currencies that can measure optimal foraging?

Answer 3

• net delivery rate (i.e kJ/time of worms delivered)
• energy efficiency (i.e kJ captured/kJ spent)

Question 4

What are three predictions for a two prey choice model?

Answer 4

1) predators should either only eat prey 1 (specialist) or a mixture of prey 1 and 2 (generalist)

2) the decision to specialize depends on the abundance of prey 1

3) the switch from specialist to generalist should be sudden once S1 > E1h2/E2 -h1

Question 5

Why do sharks probe humans but don’t consume them?

Answer 5

the energy output (E2) is usually less than their preferred prey (E1) even when search time is similar (S1 = S2)

Question 6

What are some risks that influence an animal’s foraging?

Answer 6

• starvation
• body reserves
• predation