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Predator Behaviors Prey selection- use experience to choose what to hunt Locating prey by vision, hear, smell One sense dominates the others
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Unit 1 Making a Living in the Wild
Chapter 7Predators and Prey
Predators and Prey
• Predators are organisms that survive by eating others (includes some plants and fungi)
• Prey is what they eat• Coevolution- changes in
both pred and prey due to their interactions
Predator Behaviors
• Prey selection- use experience to choose what to hunt
• Locating prey by vision, hear, smell
• One sense dominates the others
Examples
• Dolphins and bats use echolocation- sound waves
• Some animals use vibrations in ground or water or body heat
• Some use electrical fields in the water (sharks) called ampullae of Lorenzini
Capturing prey
• 1. Stalk and ambush- cats
• 2. Consistent pursuit- chimp hunt
• 3. Lure in prey- angler fish, less common
Hunting in groups
• Social carnivores• Can hunt larger prey• Then must share• Can use group as
defense as well
Group predation in other species
• Not just large carnivores
• Hawks• Humpback whales• Killer whales• Spiders• Ants
Handling prey
• Immobilize (stun)• Kill immediately and
take somewhere else and eat right away
• Store kill for later (cache)
Defense against predation
• Primary vs. secondary• Primary- built into body• Ex: spines• Secondary- behavior
when faced with predator
• Ex: run away, spray toxins
Secondary defenses
• 1. Flight- get away quickly
• Flagging behavior-act hurt to distract predator from young
• 2. Fight- usually when cornered, toxins
• Mobbing- diving and chirping loud to distract predator from young
Secondary defense
• 3. Freeze- silent, odorless, even may lose consciousness (tonic immobility)
Evolutionary arms race
• The better prey is at surviving, the better the predator must be to catch it
• Population size fluctuates in cycles• Both pred and prey usually stay stable• Prey usually reproduce faster than pred• Predators invest more in their young b/c
have longer lifespan