CHDV 23249 Chapter Notes - Chapter 1: Distant Relatives, Stable Theory, Lunar Phase

• School: University of Chicago
• Department: Comparative Human Development
• Course: CHDV 23249
• Professor: Misha Blizardand Christina Masco

Document Summary

Evolutionary stable theory suggests that reciprocity should evolve more easily among animals that live in kin groups. Food sharing by regurgitation of blood among wild vampire bats depends on degree of relatedness and opportunity for reciprocation. (unrelated bats will share exchange blood in captivity) In 400 hours of daylight, 110 cases of regurgitation were observed. 77 of these were between mother and her offspring in the 21/33 there was a degree of relatedness. Relatedness and association predict regurgitation independent of their correlation. Regurgitations b/w distant relatives only occur between animals that have been frequent roostmates. Three conditions must exist for reciprocity to occur: repeated pairwise interactions must occur to permit role exchanges and ensure net benefit accrues to all donors. Benefit of receiving aid must exceed the cost of donating. Donors must be able to recognize and not feed previous recipients that fail to reciprocate. Regurgitations occur primarily among frequent roostmates and close relatives.