Editing Reproductive success (section)

== Cooperative breeding ==
Evolutionarily, humans are socially well adapted to their environment and coexist with one another in a way that benefits the entire species. [[Cooperative breeding]], the ability for humans to invest in and help raise others' offspring, is an example of some of their unique characteristics that sets them apart from other non-human primates even though some practice this system at a low frequency.<ref name=":02">{{cite journal| vauthors = Kramer KL |date=October 2010 |title=Cooperative Breeding and its Significance to the Demographic Success of Humans |journal=Annual Review of Anthropology |volume=39 |issue=1 |pages=417–436 |doi=10.1146/annurev.anthro.012809.105054 }}</ref> One of the reasons why humans require significantly more non-parental investment in comparison to other species is because they are still dependent on adults to take care of them throughout most of their juvenile period.<ref name=":02" /> Cooperative breeding can be expressed through economic support that requires humans to financially invest in someone else's offspring or through social support, which may require active energy investment and time.<ref name=":02" /> This parenting system eventually aids people in increasing their survival rate and reproductive success as a whole.<ref name=":02" /> Hamilton's rule and kin selection are used to explain why this altruistic behavior has been naturally selected and what non-parents gain by investing in offspring that is not their own.<ref name=":02" /> Hamilton's rule states that rb > c where r= relatedness, b= benefit to recipient, c= cost of the helper.<ref name=":02" /> This formula describes the relationship that has to occur among the three variables for kin selection take place. If the relative genetic relatedness of the helper with the offspring is closer and their benefit is greater than the cost of the helper, then kin selection will be most likely be favored.<ref name=":02" /> Even though kin selection does not benefit individuals who invest in relatives' offspring, it still highly increases the reproduction success of a population by ensuring genes are being passed down to the next generation.<ref name=":02" />