Avoiding Predators Part 2

Question 1

Feigning Death

Answer 1

• faking to be dead to avoid predators/prevent predation

Question 2

Examples of Feigning Death

Answer 2

• hognose snake
• opossum

Question 3

Viligance Group Defense

Answer 3

Always a lookout animal in groups

have a signal to tell other members in group to do certain action to avoid predators

Question 4

Example of Vigiliance group defense

Answer 4

-meerkats and prairie dogs
- Signs of danger encourages call, signals for all to head back to safety of burrow

Question 5

Dilution Effect

Answer 5

Safety in numbers

Chances of being picked off decreases in larger and larger groups

Appear larger

Location in group matters in some circumstances

Question 6

Selfish herd hypothesis

Answer 6

middle of pack preferred to avoid getting snatched

Outer animals exposed

Question 7

How can a predator counter the selfish herd hypothesis?

Answer 7

some predators target middle, middle prey not as on guard as others, leaving them vulnerable and delayed to reaction to predator

Question 8

Why is the development of a search image by a predator dangerous for prey? What can prey do to prevent this?

Answer 8

what predator will look for and go after, mental image predator creates will make spotting desirable prey easier

prey can development polymorphisms to prevent this, can use startle effect

Question 9

In general, why are anti-predator behaviors adaptive?

Answer 9

• they will enhance chances of survival and reproduction if the behaviors change over time
• increases behavioral contribution to offspring, organisms with better defense and protection will spread advantageous traits

Question 10

How will relationship between predator and prey end?

Answer 10

Described by Prudent predation hypothesis and Group Extinction hypothesis

Question 11

Prudent predation hypothesis

Answer 11

relationship will always exist, since predators do not want to overexploit prey to extinction

Note: animals are not thinking about the future silly, lol; they are selfish and will not save for future generations; something else could wipe out the prey anyways

Question 12

Group Extinction hypothesis

Answer 12

Relationship will always continue, double negative created if all prey are gone, predators have no food

Question 13

What does the selfish herd hypothesis tell us about anti-predator behaviors of grouped animals?

Answer 13

• animals will fight over less vulnerable areas of a group to avoid predation

Question 14

What does mathematical modeling tell us about adaptive changes in behavior that predators have to make to find prey and prey have to make avoid being eaten?

Answer 14

To answer question, note patterns of equation:

As H & S increase, E will decrease (want low values as much as possible)

E constant most of the time, won’t change much

But note, prey would LOVE H & S to be bigger, keep predators away

Question 15

What type of stimuli can be used to create a startle effect?

Answer 15

• sound stimuli, bright colors, patterns

Question 16

Describe the Profitability equation

Answer 16

Profitability = Energy gained from eating/ (handling time + search time)
P = E/(H+S)

Prey – desire decreases in P engage any behavior that increase H or increase S

Predator – desire increase in P engage in any behaviors that decrease H or decrease S

Question 17

Describe the prey example regarding the mathematical model of probability

Answer 17

Prey #1: Inedible object (large opaque straw w/brown string
E = 0 joules
H = 6 seconds
S = 30 seconds

P = 0%

Prey #2: Large cryptic prey (large opaque straw w/whole mealworm)
E = 10 joules
H = 6 seconds
S = 30 seconds

P = 28%

Prey #3 smalle conscpicuous prey (clear drinking straw w/ ½ mealworm
E = 3 joules
H = 4 seconds
S = 30 seconds

P= 9%

Question 18

What do you learn from the mathematical example?

Answer 18

Animal will work for the payoff of the prey/food

animal earns less joules from less food

animals will have extreme % payoffs when only searching for 5 seconds instead of 30 (#2 at 91% and #3 at 33%, #1 still at zero)

foraging behaviors change, cause prey to avoid detection when choosing certain options