Shows data related to female reproductive success in within group competition.

1. Within Group Competition Among Female Primates

2. 3. Competition sometimes favors cooperation among females Within group competition females form alliances in some species affect access to resources affect rank acquisition Alliances often composed of kin Social bonds (friends) may also enhance reproductive success Not about rank Not about fighting for resources

3. In wild baboons, food availability limits female fitness (Amboseli)

4. High ranking female olive baboons eat more each day 30% difference in food intake between highest and lowest ranking females Modified from Barton & Whiten 1993

5. In captive olive baboons, rank affects interbirth intervals 60% shorter than wild baboons 145 days of lactational amenorrhea vs. 360 - 405 days in wild Better nutrition Little energy spent on travel High ranking females shorter: lactational amenorrhea Fewer cycles before conception Low ranking females shorter: Gestation length Lighter moms & lighter infants: Longer lactational amenorrhea More cycles before conception wild Garcia et al. 2005

6. Social bonds enhance reproductive success of female baboons + independently of high rank & ecological conditions From Silk et al. 2003

7. From Pusey et al 1997 Even though chimp females spend much time alone, rank affects fitness

8. Callitrichid females both compete and cooperate Live in small family groups Dominant female produces offspring Other group members help care for offspring Fathers/mating males help most Subordinate females don’t breed Golden lion tamarin

9. Callitrichid females both compete and cooperate Dominant females may kill subordinate female’s infants High rank affects competition Dominant females also rely on help from subordinate females Carry infants Watch for predators Help defend territory against other troops Dominant females must also cooperate with subordinates Give more grooming than they receive Not tightly connected with care or support from subordinate females Who benefits? Who benefits the most? Pygmy marmoset

10. Cooperation: In marmosets and tamarins, female RS depends on helpers