Chapter 10: Animal Behavior: Instinct, Learning, and Communication

Ethology is the scientific study of animal behavior, particularly in natural settings. Founded by Konrad Lorenz, Nikolaas Tinbergen, and Karl von Frisch (Nobel Prize, 1973), it examines behavior through Tinbergen’s four questions: causation, development, function, and evolution. Animal behavior exists on a spectrum from wholly innate (hardwired) to wholly learned, with most behaviors involving both elements.

Innate vs. Learned Behavior

Innate (Instinctive) Behavior

Innate behaviors are genetically determined and performed correctly the first time, without prior experience:

• Fixed Action Patterns (FAPs): stereotyped responses triggered by a sign stimulus (e.g., a red belly triggers territorial aggression in male sticklebacks regardless of the object’s shape)
• Kinesis: non-directional movement change in response to stimulus intensity (e.g., woodlice move faster in dry conditions)
• Taxis: directional movement toward or away from a stimulus (e.g., phototaxis in moths)

Learned Behavior

Imprinting (Lorenz): A critical-period learning process in which a young animal forms a lasting attachment to the first moving object it encounters. Konrad Lorenz famously imprinted goslings on himself. This explains why hand-raised birds fail to recognize conspecifics as mates.

Classical Conditioning (Pavlov): Associating a neutral stimulus with an unconditioned stimulus:

• Unconditioned Stimulus (food) → Unconditioned Response (salivation)
• Neutral Stimulus (bell) paired with food → Conditioned Stimulus (bell alone) → Conditioned Response (salivation)

Operant Conditioning (Skinner): Learning through consequences. Behaviors followed by rewards (positive reinforcement) increase in frequency; those followed by punishment decrease. B.F. Skinner’s “Skinner box” experiments demonstrated this with rats and pigeons.

Habituation: Decreased response to a repeated, harmless stimulus (e.g., prairie dogs stop alarm calling when a hawk repeatedly flies over without attacking).

Insight Learning: Sudden problem-solving without trial and error — documented in great apes (Pan troglodytes) stacking boxes to reach bananas (Wolfgang Köhler, 1920s).

Animal Communication

Channel	Example	Information
Chemical (pheromones)	Ant trail pheromones	Food location, alarm, identity
Visual	Peacock tail display	Mate quality, species ID
Acoustic	Frog calls, birdsong	Territory, mate attraction
Tactile	Honeybee waggle dance	Food direction and distance
Electric	Weakly electric fish	Species recognition, mate attraction

Honeybee Waggle Dance

Karl von Frisch decoded the waggle dance of Apis mellifera:

• Direction: angle of the dance relative to vertical = angle of food source relative to sun
• Distance: duration of waggle run encodes distance (1 second ≈ 1 km)
• The round dance signals food within 50m; the waggle dance for distances beyond

Pheromones

Chemical signals between conspecifics:

• Alarm pheromones: released by injured ants/bees, triggering mass defense
• Sex pheromones: Bombyx mori (silkmoth) females release bombykol; males detect single molecules over kilometers
• Trail pheromones: foraging ants lay volatile pheromones; stronger trails attract more followers (positive feedback)

Key Checklist

• I can distinguish innate from learned behavior and give examples of fixed action patterns and imprinting
• I can compare classical and operant conditioning with specific experimental examples
• I can explain how the honeybee waggle dance encodes food source direction and distance