Lec02 - Animal Behavior.docx

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Published on 28 Apr 2012
School
UTSC
Department
Biological Sciences
Course
BIOA02H3
Professor
Page:
of 7
Animal Behavior
1 animal behavior
What is animal behavior
How to genes and environment interact
What are the major types of behavior
How to animals communicate with one another?
What behavioral decisions do animals make?
Why do animal societies evolve?
How does behavior influence populations?
2 how do animals communicate with one another?
When animals interact, they exchange information
o i.e. animals communicate
communication = the reception of and response to signals
signal = causes a change in another animal’s behavior
animals communicate using signals:
o acoustical (auditory)
o visual
o chemical (olfactory)
o tactile
o electrical
3 signalling behaviors
signalling behaviors
o innate
genetically fixed
o learned
male songbirds
have species-species songs used in territorial displays and courtship
must hear song when they are nestlings, even though they do not sing it
until mature
4 what behavioral decisions do animals make?
Behavioral decisions
o Made in variable environments
o Based on a cost-benefit approach
Assume animal has a limited amount of energy for its activities, it cannot
perform behaviors if energetic cost is greater than benefits
Benefits lead to improved survival / reproductive success
Costs have three components:
o Energetic cost
Difference in energy expended if resting vs energy expended in performing
behavior
o Risk cost
Increased chance of being injured or killed as a result of the behavior
o Opportunity cost
Sum of benefits of forfeited behavior
Measure of trade offs
5 what behavioral decisions do animals make?
Animals must make many decisions about:
o Where to live
Space
o When to move / leave
Migration
o What to eat
Food and water requirements
o Which other animals to associate with
Potential mates
How do animals make these decisions?
6 habitat selection
One of the most important decisions
Cues animals use to select habitats are predictors of conditions suitable for their survival and
reproduction
Habitat provides
o Food
o Shelter
o Nest sites
o Escape routes
Some animals improve fitness by establishing a territory from which it excludes conspecifics
o Others of same species
7 migration patterns
Homing = ability to return to same place from long distances
o Pigeons
Can fly from remote sites where they have never been before
Can navigate without visual cues from environment
o Fish
E.g. salmon
Can find ‘birth rivers’ after several years
Migration = movement of a whole population with the changing seasons
o Involves genetic program
Many birds return every year to the same breeding grounds from hundreds or
thousands of miles away
Other animals migrate
E.g. monarch butterflies / whales
8 foraging behavior
Food-obtaining behavior requires
o Recognition
o Searching
o Capturing
o Eating
Optimal foraging theory
o Views forages behavior as a compromise between the benefits of nutrition and the costs
of obtaining food
o Natural selection favors foraging behavior that minimizes costs and maximizes benefits
Costs of foraging are similar to costs of territorial defense
9 mate choice and reproductive behavior
Individuals choose associates and how to interact with them
Most important choice of associates is mate choice
Choosing a mate
Influenced by energetic costs
Males:
Can fertilize many eggs
Sperm is cheap
Increase reproductive success by mating with many females
Females:
Reproductive success is limited by egg-producing costs
Eggs are expensive
Behavior:
Males
Usually initiate courtship
Compete for mating opportunities
Females
Seldom fight over males
Often reject courting males

Document Summary

What are the major types of behavior. When animals interact, they exchange information i. e. animals communicate communication = the reception of and response to signals signal = causes a change in another animal"s behavior. Animals communicate using signals: acoustical (auditory, visual, chemical (olfactory, electrical tactile. Have species-species songs used in territorial displays and courtship. Must hear song when they are nestlings, even though they do not sing it until mature. Behavioral decisions: made in variable environments, based on a cost-benefit approach. Assume animal has a limited amount of energy for its activities, it cannot perform behaviors if energetic cost is greater than benefits. Benefits lead to improved survival / reproductive success. Costs have three components: energetic cost. Difference in energy expended if resting vs energy expended in performing behavior: risk cost. Increased chance of being injured or killed as a result of the behavior: opportunity cost. Animals must make many decisions about: where to live.