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How does an animal avoid being eaten?

Explore the various strategies animals employ to avoid being eaten, including minimizing the risk of detection, attack, and capture. Learn about camouflage, mimicry, group living, and honest signals of health.

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How does an animal avoid being eaten?

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  1. How does an animal avoid being eaten?

  2. 5/27/08: Behavioral adaptations for survival Lecture objectives: • Be able to generate hypotheses and predictions for the adaptive value of a potential antipredator strategy • Recognize the antipredator benefits that might arise from living in groups

  3. Detection Attack Capture

  4. Minimize risk of detection 1. Must consider benefits and costs

  5. Minimize risk of detection 2.

  6. Minimize risk of detection 2. Crypsis (morphology & behavior) African assassin bug Hypothesis: Assassin bug “backpacking” is an adaptive antipredator behavior Predictions?

  7. Minimize risk of detection 2. Crypsis (morphology & behavior) Hypothesis: Catocala relicta (moth) perching behavior is an adaptive antipredator behaviorPredictions:1. moth background choice: 2. bird predation:

  8. Minimize risk of attack 1. Hypothesis: Anolis lizard push-ups are honest signal of health Predictions? **Human female self-defense strategies** “Crime victims are frequently chosen because they are easy targets.  Criminals prey on the weak or unsuspecting and usually avoid people who are aware of what’s going on and might put up a fight.  When out in public, look people in the eye, keep your head up and walk with confidence.” -Realistic Female Self Defense Company

  9. Minimize risk of attack 2. Stinging insects Individuals or groups? Sawfly larvae (with eucalyptus oils) Mobbing behavior: finches vs. hawk

  10. Minimize risk of attack 3. Skunks Poison dart frog Monarch butterfly

  11. Minimize risk of attack a) 4. (acoustical) Mimic:burrowing owl Model Mimic:a) an aposematic species (Batesian mimicry)b) a predator of your predatorc) your predator b) Amazon caterpillar & Mexican vine snake

  12. Minimize risk of attack c) Tephritid fly and jumping spider 4. Deceive predator (mimicry) Mimic:a) an aposematic species (Batesian mimicry)b) a predator of your predatorc) your predator Hypothesis: Tephritid fly wing-waving is an adaptive antipredator behavior Tephritid fly Tephritid fly House fly Predictions

  13. Minimize risk of (lethal) capture 1. Why might an ability to vastly outrun a predator be unlikely to evolve? Flight muscle ratio

  14. Minimize risk of (lethal) capture 2. Desert gecko hairstreak butterfly Hypothesis: Butterfly false heads help prey survive capture % escaping 30% 10% control False head

  15. Minimize risk of (lethal) capture 3. Adelie penguins vs. leopard seal

  16. Minimize risk of (lethal) capture 3. Aggregate to reduce probability of capture (dilution effect) Is there safety in numbers? The effect of cattle herding on biting risk from tsetse flies.

  17. Minimize risk of (lethal) capture A group of individuals whose members use others as living shields against predators Position of nest Snails/nest Chases/fish/hr.

  18. Minimize risk of (lethal) capture 5. Mean reaction distance (m) 40 20 0 1 2-10 11-50 >50

  19. Why do gazelles exhibit stotting behavior? H1. Alarm signal: Warns conspecifics that predator is near. H2. Confusion effect: Stotting individuals in a fleeing herd might confuse/distract a predator so that it can’t focus on one prey H3. Pursuit deterrence: Stotting advertises that the individual is in good health and is unlikely to be captured Prediction Alarm signal Confusion Deter pursuit

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