Editing Concealed ovulation (section)

===Reduced infanticide hypothesis===
This hypothesis suggests the adaptive advantage for women who had hidden estrus would be a reduction in the possibility of [[infanticide]] by men, as they would be unable to reliably identify, and kill, their rivals' offspring.<ref name="Schroder 1993" /> This hypothesis is supported by recent studies of wild [[Gray langur|hanuman langurs]], documenting concealed ovulation, and frequent matings with males outside their fertile ovulatory period.<ref name="Heisterman et al 2001">{{Cite journal | last1 = Hestermann | first1 = M. | last2 = Ziegler | first2 = T. | last3 = Van Schaik | first3 = C. P. | last4 = Launhardt | first4 = K. | last5 = Winkler | first5 = P. | last6 = Hodges | first6 = J. K. | doi = 10.1098/rspb.2001.1833 | title = Loss of oestrus, concealed ovulation and paternity confusion in free-ranging Hanuman langurs | journal = Proceedings of the Royal Society B: Biological Sciences | volume = 268 | issue = 1484 | pages = 2445–2451 | year = 2001 | pmid =  11747562| pmc = 1088898}}</ref> Heistermann et al. hypothesize that concealed ovulation is used by women to confuse paternity and thus reduce [[infanticide in primates]].  He explains that as ovulation is always concealed in women, men can only determine paternity (and thus decide on whether to kill the woman's child) probabilistically, based on his previous mating frequency with her, and so he would be unable to escape the possibility that the child might be his own, even if he were aware of promiscuous matings on the woman's part.