male mating effort is based on the number of women the male has copulated with. These men therefore invest less time in each woman and thus exhibit less sexual jealousy. Paternity certainty Paternity certainty is the extent to which a male knows or believes that a woman's child is his. In polygamous societies, men feel greater sexual jealousy when there is low paternity certainty. This is because they do not want to risk wasting time, energy and resources on a child that is not theirs. Socio-economic differences between cultures also affect paternity certainty. In a natural fertility country such as Namibia, 96% of males show sexual jealousy. Additionally, there is greater likelihood of paternity loss and paternity uncertainty when there is a lack of contraceptives. This provides an explanation for why industrialised countries tend to show lower sexual jealousy compared to pre-industrialised countries. See also Compersion Mate guarding in humans References External links Further information on jealousy and mate-guarding in males and females Jealousy Ethology Evolutionary psychology Sexual fidelity Sexual emotions Sexual jealousy