Animal Behavior
Chapter 45
Mader: Biology 8th Ed.
Outline
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Genetic Basis
– Nature versus Nurture
Learning
Female Choice
Male Competition
Dominance Hierarchy
Territoriality
Communicative Behavior
Sociobiology and Animal Behavior
Altruism versus Self-Interest
Mader: Biology 8th Ed.
Genetic Basis
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Two basic types of behavioral questions:
– Mechanistic
– Survival Value
Both recognize behavior, observable and
coordinated responses to environmental
stimuli, has at least a partial genetic basis.
– Genes influence development of neural
and hormonal mechanisms controlling
behavior.
Mader: Biology 8th Ed.
Nature or Nurture
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Nature (inherited) versus nurture
(environmental) questions have been, and
are still, constantly debated.
– Studies on identical twins can be used to
determine extent of inherited behavior.
 Genetically identical twins raised
separately are sometimes remarkably
similar.
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Behavior Undergoes Development
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Some behaviors seem to be stereotyped.
– Fixed Action Patterns (FAP’s)
 Originally assumed to be elicited by a
sign stimulus.
 Increasingly thought to develop after
practice.
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Pecking Behavior of Laughing Gull Chicks
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The Phenomenon of Learning
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Operant Conditioning
– Gradual strengthening of stimulusresponse corrections.
 Trick-training in birds.
Imprinting
– Imitate behavior observed during sensitive
period.
 Goslings follow any moving object after
birth.
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The Phenomenon of Learning
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Song Learning in Birds
– Brain of a bird seems to be especially
primed to respond to acoustical stimuli
during a sensitive period.
 Social experience appears to have an
even stronger influence over
development of singing.
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Behavior Is Adaptive
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Sexual selection refers to changes in
females and males, often due to differential
reproductive success, caused by mate
choice and competition for mates.
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Female Choice
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Courtship displays help males and females
recognize each other for successful mating.
– Good Genes Hypothesis
 Females benefit from selective choice
by securing sperm with good genes.
– Run-Away Hypothesis
 Females choose mates on the basis of
traits that make them attractive to
females.
Mader: Biology 8th Ed.
Male Competition
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Cost-benefit analyses have been conducted
to determine if the benefit of access to
mating is worth the cost of competition
among males.
– Positive effects (benefits) must outweigh
negative effects (costs) if the behavior is
to continue.
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Dominance Hierarchy
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Males and females have separate dominance
hierarchies.
– Higher-ranking individuals have greater
access to resources.
 Baboons form temporary consort pairs
with females.
 Males may monopolize estrous
females.
 Or may assist females or form
friendship groups to secure future
matings.
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Female Choice and Baboon Male Dominance
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Territoriality
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Territoriality is protecting an area against
other individuals.
– Red Deer Stags (males) compete for
groups of hinds (females).
 Hinds only mate with one stag.
 Harem Master must be large and
powerful to fight off challengers.
 Less body fat, thus may be more
likely to starve in bad times, and
have shorter life span.
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Competition Between Red Deer Stags
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Animal Societies
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Members of a society are organized in a
cooperative manner that extends beyond
sexual and parental behavior.
Communicative Behavior
– Chemical
 Pheromones designate chemical
signals that are passed between
members of the same species.
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Communicative Behavior
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Auditory
– Faster than chemical communication.
– Can be modified by loudness, pattern,
repetition, and duration.
Visual
– Used by species active during the day.
 Contests between males make use of
threat postures.
 Save energy by avoiding fighting.
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Communicative Behavior
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Tactile
– Occurs when one animal touches another.
 Gull chicks peck at the parent’s beak in
order to induce the parent to feed them.
 Foraging honeybees return to the hive
and perform a waggle dance that
indicates the distance and direction of a
food source.
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Communication Among Bees
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Sociobiology and Animal Behavior
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Sociobiology applies the principles of
evolutionary biology to the study of behavior
in animals.
– Assume individuals derive more
reproductive benefits than costs from
living in a society.
 Other advantages include predator
avoidance, assistance in rearing
offspring, and finding food.
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Sociobiology and Animal Behavior
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Societal Disadvantages
– Crowding
 Resource allocation.
 Spread of disease.
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Altruism versus Self-Interest
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Altruism is behavior that involves a
reduction in direct fitness that may be
compensated by an increase in indirect
fitness.
– Inclusive Fitness includes both personal
reproduction and reproduction of relatives.
 Genetic relatedness may underlie
many/most acts of apparent altruism.
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Nest Helpers
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Green Wood-hoopoes
– One breeding pair per flock.
 Other sexually mature members may
help feed and protect fledglings and
protect the home territory.
 Helper is contributing to survival of its
own kin.
 Helper is more likely than nonhelper
to inherit parental territory.
Mader: Biology 8th Ed.
Migratory Behavior in Blackcap Warblers
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Feeding Behavior of Garter Snakes
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Review
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Genetic Basis
– Nature versus Nurture
Learning
Female Choice
Male Competition
Dominance Hierarchy
Territoriality
Communicative Behavior
Sociobiology and Animal Behavior
Altruism versus Self-Interest
Mader: Biology 8th Ed.
Mader: Biology 8th Ed.