The few remaining human hunter-gather societies have social networks like those typical for Facebook. Human hunter-gather groups consist predominately of persons who are not genetic kin, although brothers and sister often are part of the same group. Moreover, young adults of both sexes sometimes remain within their natal group, and sometimes disperse. Relationships between hunter-gather groups are often friendly, with visiting and migration common. In these senses, hunter-gather groups are like groups of Facebook friends
More generally, humans typically form multi-level, nested structures of alliances and a fission-fusion pattern in daily life. Human adults typically form pair bonds associated with a stable, recognized living space for the pair and its dependents (a family). At the same time, human families live within a larger, relative stable physical and social community. In addition, humans readily associate with strangers in small groups for particular daily purposes. These social patterns contain elements found in the social structure of humans’ nearest living primate relatives, the African great apes. No ape, however, has as many types or number of conspecific social relations as do humans.
The explanation for humans’ extraordinary evolutionary distinctiveness remains unclear. Important recent work points to the development of pair bonds and paternal recognition within cooperative raising of young. Particular socially generated and maintained inventions or, at least in part, fortuitous, cumulative cultural developments, also are a second leading idea in current evolutionary ethological research.
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 See Hill, Kim R., et al. “Co-Residence Patterns in Hunter-Gatherer Societies Show Unique Human Social Structure.” Science. 331 (2011): 1286-1289.
 Humans have sexual bonds like gorillas (minus the polygyny), adult male bonds like chimpanzees (but perhaps less violently competitive), adult female bonds like bonobos (but probably less lesbian sex), and weak ties like orangutans. For primate comparisons and analysis, see, e.g. Lars Rodseth and Shannon A. Novak, “The Impact of Primatology on the Study of Human Society,” pp. 187-220 in Barkow, Jerome H. 2006. Missing the revolution: Darwinism for social scientists. Oxford: Oxford University Press.
 See Chapais, Bernard. 2008. Primeval kinship: how pair-bonding gave birth to human society. Cambridge, Mass: Harvard University Press.