Lec17: Anti-predator behavior

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Course Introduction and Exam Information

Predators develop search images through perceptual learning
Remember successful prey types from past experiences
Octopus and squid examples:
- Mimic octopus video demonstration (content removed due to copyright)
- Octopus can change color patterns to mimic predators
- Create appearance of two large forward-facing eyes (predator characteristic)

Müllerian mimicry:
- Multiple poisonous species evolve similar appearance
- All species benefit from shared warning signals
- Example: Vespid wasps with yellow and black bands
- Predator learns to avoid all similar-looking species after one bad experience
Batesian mimicry:
- Non-poisonous species evolve to resemble poisonous ones
- Example: Monarch butterfly (poisonous) vs Viceroy butterfly (non-poisonous mimic)
- Birds learn to avoid monarchs, also avoid viceroys
- Multiple species evolved to mimic monarchs

Advantages of ground nesting:
- Clear view of approaching predators
- No concealment obstacles
Disadvantages:
- Nest not well concealed
- Vulnerable to ground predators (foxes, cats)

False nest behavior:
- Similar to male stickleback creating false nest
- Pretend to nest in wrong location to lead predators away
Rodent mimicry:
- Duck into tall grass, scurry while squeaking like rodent
- Predators find rodent sounds irresistible
Direct approach:
- Run or fly directly at predator
- Call loudly, turn away at last second
- Move away from actual nest location
Broken wing display:
- Act injured, unable to fly
- Drag wing along ground
- Predators can't resist apparently easy prey
- Lead predator away from nest area

Definition: Reduce chances of being killed when already caught
Tonic immobility ("playing dead"):
- Physiological response, not conscious decision
- Innate fixed action pattern
- Triggers: Vision of two predator eyes facing animal
- Chick behavior:
  - Remain completely motionless
  - Occasionally peek to check if predator still present
  - Continue immobility if stimulus (predator eyes) still visible
  - Resume normal behavior when stimulus removed

Professor's hamster experience:
- Female escaped cage
- Froze completely when light turned on
- Could touch and move limbs without animal responding
- Response lasted several minutes
Other examples:
- Opossums (most well-known)
- Rabbits can enter this state
- Hamsters respond to specific predator odors (cat-like animals, certain dog species)

Three major benefits:
1. Dilution effect ("selfish herd"):
  - More animals = lower individual probability of being caught
  - Colonial reproduction reduces individual nest attack probability
2. Reduced vigilance demands:
  - Many eyes increase predator detection probability
  - Individual animals can spend more time foraging
  - Quick communication of danger through group
3. Confusion effect:
  - Mass escape confuses predators
  - Often results in no successful captures
Costs of group foraging:
- Increased competition for food resources
- Interference with individual activities
- Worse conditions for non-dominant individuals

Examples seen in course:
- Jackdaws (Lawrence's description)
- Geese (video examples)
- Meerkats (video)
Blackheaded gull study data:
- Center of colony: Highest mobbing rate, lowest egg loss
- Edge of colony: Lower mobbing rate, higher predation success
- Conclusion: Mobbing is effective anti-predator behavior

Autotomy (self-amputation):
- Mollusks: Shed meaty tentacles when attacked
- Lizards: Tail shedding
  - Move tail more than rest of body to attract attacks
  - Shed tail continues wiggling, distracts predator
  - Tailless lizard escapes

Altruistic benefits:
- Warn other animals of danger
Costs to caller:
- Position betrayed to predator
Selfish benefits:
- Elicit mass escape for dilution/confusion effects
- Get head start on escape
- Sometimes used falsely to access food resources

Subject: Animals feeding on fat worms in shallow water
Findings:
- Non-callers most likely to be attacked
- Late fliers most likely to be attacked
- Callers (despite position betrayal) less likely to be caught
- Interpretation: Predators avoid vigilant animals that detected them first
- Alarm calls can attract predators of the predator

Two distinct predator types require different responses:
1. Peregrine falcons:
  - Attack from above in rapid dive
  - Best response: Crouch low, remain still
2. Sparrow hawks:
  - Attack flying low above ground
  - Best response: Fly up when detected
Distinct alarm calls: Indicate which escape method will be used

Definition: High energy leaping while fleeing from predators
Observed in: Thompson's gazelles fleeing from cheetahs
Characteristics:
- Takes extra energy and time
- Makes animal more visible to predator
- White rump patch creates "flag" effect visible to pursuing cheetah
11 different hypotheses proposed
Caro 1986 study findings:
- Cheetah attacks deterred by stotting behavior
- Interpretation: Signal meaning "I'm far enough away with high escape probability"
- Deters predator attack, saving energy for both predator and prey
- Data shows higher success rates for animals that stot

Great Escapes video (Marty Stouffer):
- Bobcat attack examples
- Bobcat-pig interaction analysis:
  - Bobcat had recently killed prey
  - Killing bite motivation reduced below threshold
  - Stalking/attacking motivation still high
  - Action-specific potential for killing builds slower than other predatory behaviors
  - Similar to Lorenz and Leyhausen's findings
- Big cat behavior: Will catch prey without killing when well-fed, bring to young for practice
- Bobcat chasing lizard tail (autotomy example)

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