> Wait but, if they're so helpful, why didn't they evolve in our fellow ape species too? Apes have vastly different social structures than humans. Those struc

> Wait but, if they're so helpful, why didn't they evolve in our fellow ape species too? Apes have vastly different social structures than humans. Those structures do not encourage those traits. Apes have strict ranking and group around families. In chimps, females emigrate after puberty and permanently relocate to other groups. Fertility is used as a passport to join a new group. Constant fertility would be disruptive. Humans want to have sex constantly because it helps form large communities. The possibility of mating bonds together many nonfamily groups. Humans do better in large groups, so attractive features are selected for much more strongly. In ape groups it doesn't matter, because they simply accept or reject new apes based on the size of the group and availability of resources.