1. Unit 1 Making a Living in the Wild Chapter 7 Predators and Prey

2. 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

3. Predator Behaviors Prey selection- use experience to choose what to hunt Locating prey by vision, hear, smell One sense dominates the others

4. 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

5. Capturing prey 1. Stalk and ambush- cats 2. Consistent pursuit- chimp hunt 3. Lure in prey- angler fish, less common

6. Hunting in groups Social carnivores Can hunt larger prey Then must share Can use group as defense as well

7. Group predation in other species Not just large carnivores Hawks Humpback whales Killer whales Spiders Ants

8. Handling prey Immobilize (stun) Kill immediately and take somewhere else and eat right away Store kill for later (cache)

9. Defense against predation Primary vs. secondary Primary- built into body Ex: spines Secondary- behavior when faced with predator Ex: run away, spray toxins

10. 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

11. Secondary defense 3. Freeze- silent, odorless, even may lose consciousness (tonic immobility)

12. 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