Animal Behavior

1
Animal Behavior

• Chapter 45

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Outline

• Genetic Basis
• Nature versus Nurture
• Learning
• Female Choice
• Male Competition
• Dominance Hierarchy
• Territoriality
• Communicative Behavior
• Sociobiology and Animal Behavior
• Altruism versus Self-Interest

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Genetic Basis

• 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.

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Nature or Nurture

• 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

• Some behaviors seem to be stereotyped.
• Fixed Action Patterns (FAPs)
• 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

• Operant Conditioning
• Gradual strengthening of stimulus-response
  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

• 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.

9
Behavior Is Adaptive

• Sexual selection refers to changes in females and
  males, often due to differential reproductive
  success, caused by mate choice and competition
  for mates.

10
Female Choice

• 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.

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Male Competition

• 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

• 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

• 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

• 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

• 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

• Tactile
• Occurs when one animal touches another.
• Gull chicks peck at the parents 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

• 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

• Societal Disadvantages
• Crowding
• Resource allocation.
• Spread of disease.

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Altruism versus Self-Interest

• 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

• 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.

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Migratory Behavior in Blackcap Warblers
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Feeding Behavior of Garter Snakes
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Review

• Genetic Basis
• Nature versus Nurture
• Learning
• Female Choice
• Male Competition
• Dominance Hierarchy
• Territoriality
• Communicative Behavior
• Sociobiology and Animal Behavior
• Altruism versus Self-Interest

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