In monogamous relationships, one male mates with one female and remain together for a long period of time as a pair. We currently believe that the reason for monogamous relationships in mammals is because it is advantageous for the offspring between the mates, since the male will have greater reproductive fitness, which results in viable offspring that live longer after the female has provided the care for it. Although the opportunities for reproduction are there for males to engage in polygamous relationships, it is more beneficial for males to engage in monogamous relationships so that they can guarantee that an offspring will be theirs. On the other hand, females can guarantee that an offspring will be theirs, but they can only provide so much care for the offspring since paternal care will be required as the offspring grows and matures. Monogamous relationships in mammals also occur so that males can secure a mate in a population with a low density of females.
Opie (et al.) discuss that the cause of social monogamy in primates is male infanticide, in which infants are killed by males. Due to long lactation periods, infants, particularly primates, are especially vulnerable to infanticidal males. These males resort to killing the offspring of competitors, which allow the females to become more available to mate again by shortening lactation periods. Through socially monogamous relationships, mates are able to provide biparental care for the offspring by protecting them if necessary. Lukas (et al.) claim that there is no apparent association between the evolution of social monogamy and male infanticide, which is in opposition to Opie (et al.). Males are unable to engage in polygamous relationships due to the fact that females are intolerant of each other and that population densities are low. Increased paternal care is a consequence of social monogamy, as they claim, as it is advantageous for males to secure a mate in populations with low female densities by providing resources and effort. The evolution of social monogamy transitioned from the condition of solitary living in ancestral species. Once again, females are intolerant of each other, so they live in territories that do not overlap and engage with males that roam.
The article that I think provides a more convincing scientific argument would be “The Evolution of Social Monogamy in Mammals” by Lukas (et al.). Their argument consisted of data following the proposal of a cause of social monogamy in the form of statistical tests. I disagree with Opie (et al.) based on their claim that social monogamy in primates is solely led by male infanticide, seeing that Lukas (et al.) suggested that female competition, female intolerance, and low female densities play a role in the evolution of social monogamy. In the Lukas (et al.) article, a diagram is provided to illustrate that there must have been a transition from an ancestral condition of solitary females and roaming males into social monogamy. Lukas (et al.) also seem to be more convincing because their article contains numerous statistics that are explained with given sample sizes and direct analysis of it.
After reading these articles, my understanding of monogamy in primates has definitely changed. I knew that because females can guarantee that an offspring would be theirs, it would make sense for males to put forth the effort in engaging in monogamous relationships in order to increase their reproductive fitness. My understanding of the evolution of social monogamy was enhanced through reading that it all started from an ancestral condition and there was a visual flow chart that showed the transition of the evolution. My understanding also changed because these articles provided information about the advantages of social monogamy. What I found to be most surprising from what I read was about the male infanticide and its relation to social monogamy in primates. The reasoning for male infanticide was provided thoroughly in the articles.