chapter 11 Flashcards
do bats take paths that target the best food items or the first food item
they take a path that targets the best food items
foraging behavior
searching for and consuming food. It makes up a large part of the time budget of many animals
search image theory
animals encounter a prey type more and more they become more successful in finding that type of prey
optimal foraging theory (OFT)
A class of mathematical models that are collectively known as OFT
what questions do the three models of optimal foraging theory suggest
What food items should a forager eat?
How long should a forager stay in a certain food patch?
How does variance in food supply affect a forager’s decision about what food types to eat?
OFT what to eat? What does each prey item have? What is the profitability of a prey item?
- kind of food (meat, plants, etc.)
- size of food (small deer vs big deer)
Each prey item has
1. Energy value (300 cal)
2. Encounter rate (every 3 min)
3. Handling time (takes 2 min to kill and ingest)
Profitability of a prey item: energy/handling time the greater that ratio, the more profitability of prey type
what does the model of what to eat assume
- Energy intake from prey can be measured in some standard currency (for example, calories).
- Foragers can’t simultaneously handle one prey item and search for another.
- Prey are recognized instantly and accurately.
- Prey are encountered sequentially.
- Natural selection favors foragers that maximize their rate of energy intake
if the encounter rate of prey 1 is above the critical value what prey is taken? what if it is below the critical value
Above only prey 1 is taken
Below both prey 1 and prey 2 are taken
how long does a forager stay in a patch that is depleting
A forager should stay in a patch until the rate of food intake associated with the next food item in its patch is equal to that
of the average rate of food intake across all patches available. The food intake in that patch is equal to the average amount of food it could get in other patches, given that it has to pay a cost to get to such other patches.
- The greater the time between patches, the longer a forager should stay in a patch.
Increased travel time leads to an increase in the costs associated with such travel - A forger should remain longer in patches if patch quality in the environment is poor versus rich. In order to make up for the travel costs associated with a move from a patch, a forager has to stay longer in a poor patch than in a good patch to obtain a fixed amount of energy
what kind of foragers are risk averse
somewhat full, they prefer to forage in patches with low variance (they always have access to food so a small meal doesnt need to be very nutritious)
what kind of foragers are risk prone
hungry foragers who prefer high variance patches (doesnt come into contact with food often so it needs nutritious, valuable food to give them enough energy to survive)
more people in a group
the more food per individual in the group ex: Tai chimps and the more learned through the observation of others
public information
information based on the actions of others as a cue to changes in environmental conditions
who should leave a poor patch first social or solitude foragers
Public information models predict that social foragers in poor patches
should leave such patches earlier than solitary individuals, because
social foragers can use the failed foraging attempts of their groupmates as additional information about when they themselves should leave a patch of food.
is the hippocampus larger or smaller in species with a lot of food storing behavior
larger
animals in harsh environments have what hippocampal size
larger
larger forebrains are associated with what
superior learning abilities and higher behavioral plasticity
explain pigeon producers and pigeon scroungers
producers find food; scroungers follow producers and eat the food that producers have uncovered
what does scrounging in pigeons block
scrounging blocked cultural
transmission of foraging skills
what is the marginal value theorum
predicts how long a forager should stay in a given patch, given that it can leave and travel to feed in less depleted patches.
