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Cooperation. Hear it. Web cam. Paul Sherman. Benefits of cooperation:. 1) Direct benefits. Benefits of cooperation:. 2) Reciprocity. Bonobos : steep dominance hierarchy; Food sharing only under pressure Dominant individuals gain, others lose, no reciprocity
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Web cam Paul Sherman
Benefits of cooperation: • 1) Direct benefits
Benefits of cooperation: • 2) Reciprocity
Bonobos: steep dominance hierarchy; • Food sharing only under pressure • Dominant individuals gain, others lose, no reciprocity • Chimps: shallow dominance hierarchy; • Food sharing is more common • Past food received was best predictor of food giving
Regurgitators are more likely to be related and more likely to be roostmates than the general population
Vampire bats display all the requirements for reciprocal altruism • Stable group • Many chances for altruism through lifetime (20 yr) • Individuals remember • Donor and recipient have a symmetrical relationship • However, feedings between non-kin are very rare!
9 bats held in captivity • Food withheld from a different individual each night • Regurgitation events recorded • Hunger did not dictate if individuals received help from cagemates • Hungry individuals were more likely to receive help from an individual they had fed before
Benefits of cooperation: • 3) Benefits to relatives (Kin selection)
Would you lay down your life for your brother? • No, but I would lay down my life for two brothers or eight cousins… • JBS Haldane