ANSC 3180 Lecture Notes - Lecture 16: Aestivation
2 May 2018
School
Department
Course
Professor
The search for, and intake of food
•
Location of food
○
Pursuit of animal prey
○
Selection of plant food
○
Handling and ingestion of food
○
Location, apprehension, ingestion
•
Foraging:
Energy expenditure
•
Time expenditure
•
Increased thermoregulatory costs
•
Increased risk of predation
•
Decreased territorial defense activities
•
Potential consumption of toxins/antinutrients
•
Foraging Costs:
Satiety -no longer feeling hungry
•
Individual survival
•
Successful reproduction -species survival
•
Foraging Benefits:
minimize time and energy spent
○
Maximize digestible/metabolizable energy intake
○
Benefits must outweigh the costs
•
No longer cost effective to forage for food
○
Loose less energy standing in sheltered area
○
Use more energy foraging and thermoregulation than gained in food found
and eaten
○
E.g. deer yarding in winter
•
If same energy required to catch small or large prey, large prey will
provide more energy and nutrients
○
BUT consider risk of predation and thermoregulation involved in catching
different prey items
○
E.g. carnivores
•
Foraging: a cost-benefit equation
Low food density -if too scattered will require too much energy and time to
harvest
•
Low food availability -snow/ice may reduce availability
•
Forage for larger prey species
○
Become less selective
○
Choose foraging areas more selectively
○
As food density/availability decreases:
•
Eventually, animal spends more time and/or energy to obtain the same amount of
energy and nutrients
•
Finally, animal cannot meet energy and nutrient requirements, even by
continuous foraging
•
Hibernation, daily/seasonal torpor
○
Estivation
○
Migration (mammal and bird)
○
Reduce foraging activity, decreased body temperature, decreased BMR
○
So…
•
Strategy:
Foraging
Friday,)April)7,)2017
12:20)PM
