Lesson 10: Foraging Behavior

Question 1

human beings are what kind of predators

Answer 1

visual

Question 2

some other sensory modalities

Answer 2

• vibration detection
• taste ( a form of chemoreception like smell))
• heat detection
• electroreception

Question 3

lateral line system

Answer 3

• fish have a series of sensory structures that detect movement in the water
• can compare info from both sides of body to localize source of movement

Question 4

external chemical senses

Answer 4

fish also can sense chemicals in water from ‘external taste’ receptors

Question 5

how do catfish track their prey if they live in murky water

Answer 5

• water movement (vibration)
• external taste ( dissolve chemicals in water)

Question 6

Catfish Experiment

Answer 6

Observed Catfish hunting individual guppies - and used infared video system to track movement of both predator and prey in complete darkness

Identified 3 types of movement
1.) path following
2.) head-on encounters
3.) attack on stationary guppy

Results

• 80% of attacks occured on moving guppies
• catfish usually followed the same path as the guppy before the attack

Question 7

Lateral Line Structures (more for the catfsish)

Answer 7

• hair cells are mechanoreceptors sensitive to deflections caused by water movements
• organized into “neuromast organs” distributed along the length of the body

Question 8

Catfish Experimental Approach

Answer 8

Manipulated either:
1.) External gustation aka taste (reduced ability to detect chemical cues)
OR
2.) lateral line (reduced ability to detect hydrodynamic cues)

RESULTS:
Intact (control - 65%
External chemical detection ablated - 60%
Ablated lateral line - 17%

^^^
Suggests that lateral line is more important than taste in terms of success

Question 9

Electroreception in Sharks

Answer 9

electroreception is the ability to detect electric fields - an electric field can travel from its source in water but not in air, so it is useful for aquatic species

Question 10

Electroreception in Sharks (Tank + Setup )

Answer 10

the testing tank had a sandy bottom - water entered the tank through a buried pipe and emerged from the sand near the other side of the tank

• a special agar holding chamber was connected to the inflow pipe so that water could pass through the chamber and out the other side

Question 11

Electroreception in sharks experiment

Answer 11

a.) buried live flounder – accurate attack
b.) live flounder in an agar chamber (control) – accurate attack
c.) flounder pieces in agar chamber – attack at displaced odor site
d.) buried live flounder with plastic insulation – no attack
e.) plain electrodes – attacked
f.) plain electrodes vs. actual chunk of dead fish – attacked electrodes first

Question 12

lemurs

Answer 12

• small primates from the island of Madagascar
• almost entire nocturnal and feeds mostly on fruit and insects

Question 13

lemur experiment

Answer 13

1.) trained lemurs to remove plastic lid from a bowl in order to get a mealworm
2.) then did choice experiment in which the lemurs had to identify which of the two bowls had the mealworm

Question 14

Different cues : lemur experiment

Answer 14

olfactory cue: live mealworm in cup
No olfactory cue: live mealworm in air-filled bag

auditory cue: live mealworm in cup with paper
no auditory cue: dead mealworm in cup with paper

Question 15

lemur experiment: results

Answer 15

3 modalities: best chance
2 modalities: V+A and V+O were the best (needed visual)
1 modality: visual was the best

Question 16

evolutionary arms race

Answer 16

back and forth process of adaptation and counteradaption

Question 17

counteradaption

Answer 17

in predators – adapt to better detect hidden or cryptic prey

Question 18

2 possible behavioral counteradaptions if prey are cryptic

Answer 18

• search rate hypothesis
• search image hypothesis

Question 19

search rate hypothesis

Answer 19

animal detects cryptic prey and then slows rate of search to find more

Question 20

search image hypothesis

Answer 20

animal forms a mental image which helps it focus on the visual features of the prey

Question 21

bobwhite foraging: search rate hypothesis

Answer 21

• trained birds to feed on food pellets on the floor of a large room
• then tested birds to see what happened if the pellets were hard to see

Question 22

bobwhite foraging results:

Answer 22

the more cryptic the prey, the more slowly the birds walked around the room

Question 23

blue jay foraging: search image hypothesis

Answer 23

• trained birds to search for month images on a computer screen
• started with easy-to-see moths and then swithed to cryptic ones (used catocala retecta)

Question 24

blue jay foraging experiment and results

Answer 24

1st run: no moth or catacola relicta
2nd run: no moth or catacola retecta
3rd group or “non run”: no C. retecta or C. relicta or no moth

RESULTS
- in both of the run treatments (just one species in the run), the percent of correct responses increases

• in the nonrun treatment (both species mixed in) the percent of responses did not change over trials

CONCLUSTION
- this implies that the visual appearance of the moths mattered to the jays - otherwise the nonrun would not have differed from te run

Question 25

foraging and cognition

Answer 25

because foraging is a fundamental activity of animals and of such greater importance, we often can observe the “thinking” of animals when they are foraging

Question 26

Yellow eyed junco experiment

Answer 26

if practice makes perfect, then the older animals should be better at certain tasks than the younger ones
- presented mealworms of different sizes to different ages of bird: recently fledged, young and older juveniles, as well as adults

Results:
- adults had the lowest handling times and the highest energy intake
- suggests that adults had learned with practice AND the benefit is greater efficiency

Question 27

do animals teach their offspring

Answer 27

teaching is defined ass “active participation” of an experienced individual in facilitation learning by a native individual

Question 28

how can we tell if teaching is happening

Answer 28

• teacher modifies its behavior only in the presence of a pupil
• the pupil acquires knowledge or skill more rapidly due to the behavior of the teacher
• the behavior is costly to the teacher (this is debatable)

Question 29

white-tailed ptarmigan hen experiemnt

Answer 29

Observaiton: chicks follow mothers for several weeks, mother will drop food and give a unique vocalization, a food call. chicks run to the mother and feed (looks like the hen is teaching her chicks)

Hyptothesis: hens teach chicks what food plant to eat
Prediction: chicks should primarily eat foods associated with their mother’s food calls (recall that chicks are precocial so mostly select their own foods_

To test this:
- observed 7 hens and their chicks
- recorded food eaten by hen and her chicks
- recorded all food calls given by hen and the food plant associated with the call

Results: there was a positive correlation between the proportion of food calls associated with a plant species and the proportion of that plant in the chick’s diet

Conclusion: chicks learn their diet from their mother’s food calls

Question 30

Tool use video examples

Answer 30

• dog moving a chair
• heron using bread to lure a fish
• badger using a small log as a ramp to escape an enclosure

Question 31

capuchin monkey using stone to open nuts

Answer 31

• stones vary in their size, weight and composition, which affects their fragility (fragile sandstone will break before cracking the nut)

wanted to know how individuals select the correct stones to open hard nutes
— visalberghi

Question 32

capuchin tool use experiment

Answer 32

wanted to know how individuals select the correct stones to open hard nuts

Methods:
- offered individuals a nut and stones that different in functionality based on type (soft sandstone or hard quartzite_, r size and weight (heavy or light_
- recorded the first stone used to hit the nut - that is, which stone did the money pick first

• repeated 5 times with different combinations of stones

Results: in each experiment, individuals used the more functional stone based on its composition, size, and weight

Conclusion: capuchins can access the relevant features of a stone tool based on its size, weight, and composition

Question 33

elephants displaying insight learning

Answer 33

• insight learning occurs when an animal solves a problem by “thinking it out” and not by “trial and error”
• with no experience, Kandula (elephant) moved a large cube underneath hanging fruit to stand on it and obtain the food
  – hard to demonstrated becasue the animal needs to have no prior experience

Question 34

dolphin tool use:

Answer 34

dolphins use marine sponges to protect their snouths as they hunt bottom-dwelling fish: the seafloor is strewn with sharp rubblr and they’d get all scraped up otherwise

Question 35

dolphin tool use: example of social learning

Answer 35

this is a learned behavior that mothes pass on to offspring - mostly daughters, apparentlt, females soend years with their calves and “sponging’ for fish is a fairly low cost way to get food, since the mother is with the offspring so long, there is time to teach them

Question 36

why don’t female dolphins teach their sons

Answer 36

sons disperse away from home and won’t live i nthis area in the future so there is no reason for mothers to go to the effort of teaching them

Question 37

crows can make tools for retrieving food

Answer 37

humans aren’t the only ones to make tools

Question 38

decisions on what to eat: numerical competency in new zealand robins

Answer 38

researchers designed a branch with 2 covered cache sites
- while the robin watched, researchers placed different numbers of mealworms one at a time in caches, then released the bird and recorded which cache was chosen first
- when the total number of food items in both caches was less than 10, robins preferred larger cache (items above dashed line yielded results that were significantly different from random)

• in a second experiment, researchers mixed mealworms with rocks so that each cache had the same number (and volume) of objects, but different numbers of mealworms