introduction to animal behavior and welfare

1. Lecture 1: Introduction
to Animal Behavior
&
Lecture 2: Ethology

2. Lecture outline
1. Introduction to course (schedule,
policies, etc…)
2. Four categories of questions
addressed in animal behavior studies
3. Origins of animal behavior as a field
of study
4. The Ethological approach
• Review: Principles of Evolution
• Ethological methods
• Key concepts in ethology

3. Four categories of questions
(Niko Tinbergen, 1963)
 What are the mechanisms that cause
a behavior?
 How does a particular behavior
develop (within the individual’s
lifetime)?
 What is its survival value? (current)
What’s the “working hypothesis”? Is it necessarily
true?
 Why did it evolve? (past)

4. Origin of animal behavior as a
field of study
 Ethology
Evolutionary perspective
Primarily field-based
Wide range of animals studied
 Psychology
Mechanistic/Developmental perspective
Primarily lab-based
Focused primarily on mammals

5. Ethology: Review of Principles
of Evolution
 Evolution: Change in the frequency of
alleles /genotypes in the population over
time (>1 generation)
 Adaptation: A phenotypic trait that
helps an individual survive/reproduce
 Genotype vs. phenotype: What is the
difference?

6. Ethology: Review of Principles
of Evolution (cont.)
 Natural selection: Differential reproduction of
genotypes leads to persistence of those
genotypes that enable an individual to
survive/reproduce most effectively.
Example: Change in antibiotic resistance of the
tuberculosis bacterium.
 Only traits that are variable and inheritable
are subject to natural selection.
Example: Rabbit camouflage
 Where does variability come from?

7. Maintenance of non-adaptive
traits
 Pleiotropy: Multiple effects of a single gene
 Linkage: Gene for non-adaptive trait located
near gene for highly adaptive trait
 Gene flow: Populations in different
environments move between habitats, may
interbreed
Ex: Funnel-web spiders
 Time lag: Non-adaptive traits are being
selected against, but are not yet completely gone

8. Ethological methods
 Comparative approach
Overall concept: Behavioral differences among
related species are due to environmental differences
 Example: Comparisons of ground-nesting and cliff-nesting
gull species (Esther Cullen, 1957)
 NOTE: More details of this study in Signs and Signals video
Benefits of this approach
 Be able to explain…
Limitations of this approach
 Be able to explain…

9. Ethological methods (cont.)
 Experimental approach
Overall concept: manipulate variables in field or
lab and observe/measure consequences.
 Examples: “Classical” experiments in Signs and Signals video
Wednesday (studies by Karl von Frisch, Niko Tinbergen and
Konrad Lorenz)
Benefits of this approach
 Be able to explain…
Limitations of this approach
 Be able to explain…

10. Key concepts in ethology
 Fixed action patterns
Can be initiated by environmental stimulus,
but proceed to completion
 Ex: graylag goose egg-rolling behavior
Occur in unalterable (stereotyped) sequence
 Minor alterations may occur
Are not learned (are innate)
Can be triggered inappropriately
 Ex: stickleback response to unrealistic models, etc.
Performed by all appropriate members of a
species

11. Key concepts in ethology (cont.)
 Sign stimuli and releasers
Function: Serve to trigger the FAP
 Example: Attack behavior in stickleback males

12. Key concepts in ethology (cont.)
 Sign stimuli and releasers (cont.)
Supernormal stimuli
 Examples…
Mimicry
 Examples…
Role of motivation

13. Key concepts in ethology (cont.)
 Chain of reaction
Sequence of events
Example: stickleback
courtship
Each behavior of one partner
serves as a sign stimulus for
the other partner

14. Extension of Evolutionary Theory:
Insights into complex behaviors
 Optimal strategies: Maximize difference
between benefit and cost
Example: TIME SPENT
FORAGING
BENEFIT: Gains energy
and nutrients
COSTS:
• Risk of predation
• Energy of dealing with
competitors
• Energy and time
expended in search for and
processing food

15.  Difficulties of determining and testing
what is “optimal”: Must consider how
the behavior affects lifetime fitness
But cost/benefit analyses often done in short-
term
 Easy to run short-term experiments
 Various aspects of the behavior converted to
manageable units such as “energy”
Often mismatches between short-term and
long-term studies. Why?

16. Extension of Evolutionary Theory:
Insights into complex behaviors (cont.)
 Evolutionarily stable strategies: Two
or more strategies may be equivalent in
terms of fitness, so that all such strategies
are maintained at particular frequencies
(proportions) in the population.
Imbalances are self-correcting
Example: Two different strategies of male
salmon (Coho, King, Atlantic, others)

17.  Description of the two types of males
and their different strategies
 Costs and benefits of each strategy
considered separately
Key: Maximize number of offspring in lifetime!
 How the ratios of these strategies are
“self-correcting”
What if the proportion of large males
increases?
What if the proportion of jacks or precocious
par (small males) increases?