Animal Behavior

• Study of Animal Behavior

  Includes both behaviors that are evolved traits and those that are learned
• Questions About Behavior

  • PROXIMATE - mechanisms within the animal: HOW
  • ULTIMATE - evolutionary advantage: WHY
• PROXIMATE - mechanisms within the animal: HOW


  1. What are the biological mechanisms?

  2. What stimuli trigger the behavior?

  3. How has the animal's development influenced its behavior?
• ULTIMATE : evolutionary advantage: WHY


  1. What function does the behavior serve?

  2. How did such a behavior evolve?
• Proposed explanations for locusts switching from solitary to gregarious forms


  • Proximate: stress pheromones produced by crowded locusts stimulates others to develop into the gregarious form
  • Ultimate: aggregating into large swarms swamps out local predators, increasing the survival rate of individual locusts
  • Ultimate: locusts aggregate to capture other locusts in order to feed cannibalistically on them
  • Ultimate: epigenetic effects passed on from parents to offspring leads to switching forms
  • Proximate: individuals assess density using visual, olfactory, and tactile cues; when sufficiently stimulated it changes to the gregarious form
  • Ultimate: grouping together increases locust survival by disrupting the connections between predators' food patches
• Niko Tinbergen, Karl von Frisch, Konrad Lorenz won Nobel Prize in Physiology,For their discoveries concerning organization and elicitation of individual and social behaviour patterns.

  NiKo Tinbergen(dutch)- studied wasps and gulls and mechanisms and adaptive significance

  Karl von Frisch(austrian)- studied the dance language in bees

  Konrad Lorenz(austrian)- studied greylag geese, fixed action patterns and imprinting
• Niko Tinbergen's 4 kinds of answers to Why do starlings sing in the spring?

  • Causation: increasing daylength triggers changes in hormone levels
  • Development (ontogeny): sing because they've learned the songs from parents & neighbors
  • Fitness value (function): starlings sing to attract mates for breeding
  • Evolutionary history: starlings' songs & singing behavior evolved from simpler signals & behaviors
• Behavior as adaptation: Evolutionary History

  • Adaptation has evolutionary history
  • Natural selection: fitness differences due to available variation
  • Not best variant imaginable
  • Organisms do not "get" behavior they "need", but what works in their environment
• Behavior as Adaptation:What controls behavior?

  • Behavior has current utility
  • Behavior is tied to genes and environment, nature and nurture, intrinsic and extrinsic influences
  • Neither genes nor environment solely determine behavior, but contribute to phenotype
  • Differences in gene expression can lead to differences in behavior (and vice versa)
  • Rarely equal contributions from each end of an axis
• Behavior types


  • No modification through learning (instinct, innate)
  • Originates and is modified through learning ("nurture")
  • Highly stereotyped
  • Little variation
  • Fixed
  • Highly flexible
  • Condition dependent
• Imprinting


  • Learned appearance of parent
  • Innate tendency to learn a particular thing within a certain time period
• Innate ("instinct")

  • A behavior that is performed fully the first time it is exhibited, without prior experience
  • Can be improved with experience
  • Developmentally fixed
  • All individuals initially exhibit virtually the same behavior
• Learned

  • A long-lasting change in behavior that is the result of experience
  • Requires opportunity to learn (time)
  • Requires ability to learn (cognition / memory)
  • Requires genetic predisposition to ability
• Complex neural networks underly all behaviors

  Neral networks develop by gene-enviornment interations
• Lesson:

  -All traits are a result of interaction between genes and environment

  -Gene expression requires cellular environment

  -Environmental cues can trigger gene expression, learning, and development
• Innate Behavior

  When appropriate responses must be made quickly with:

  -little or no opportunity for learning

  -with high costs for failure

  -and with limited information available
• Innate Behaviors

  -Necessary behaviors early in life for short-lived animals

  -anti-predator responses:

  ~No chance to learn: fail one=death

  ~Moths detect bat sonar signals, fall
• Single gene affects maternal care

  • Wild type mouse: will care for offspring
  • Inactive fosB gene: will ignore offspring and care for oneself
• How single gene affects maternal care

  1. New mothers inspect newborns

  2. Smell of pups stimulates mothers' sense receptors

  3. Signal to mother's brain --> preoptic area (POA) of hypothalamus

  4. Neural signals activate fosB alleles --> FosB protein

  5. More genetic & enzymatic changes --> neural changes in POA

  6. Solicitous maternal behavior
• Blackcap warbler over-wintering


  -Breed in Europe and winter in Britain, W. Africa, or E. Africa

  -Birds that winter in britan breed during the summer in germany

  -Offsprings winter same as parent without learning

  -Different migratory tendencies due to genetic differences

  -Hybrids show intermediate migration direction
• Genetic differences can lead to behavioral differences