Among a variety of reasons for following a monogamous mating pattern, one of the main reasons is due to the viability of one offspring rather than multiple. In certain situations, especially when dealing with K-selecting species, a male can help to raise one offspring that is more likely to survive, rather than having multiple offspring with multiple mates. Primates are one species which exhibits social monogamy. Two articles titled “Male Infanticide Leads to Social Monogamy in Primates” and “The Evolution of Social Monogamy in Primates” share differing opinions as to the cause of this monogamy.
The first article, by Opie et al, describes the reason for social monogamy as a result of male infanticide. Opie et al hold that primates who have been raised by two parents are more likely to be viable and survive, but more importantly, less vulnerable to infanticidal males. The second article states a different reason, one more closely related to social structure. Lukas and Clutton-Brock maintain that monogamy has evolved due to low ratios of females to males among mammal populations. This has led to males being unable to maintain relationships with multiple females, in turn leaving more time to care for offspring from one partner.
With these differences in reasoning, I believe that the article relating social monogamy to evolutionary changes in social structure (Lukas and Clutton-Brock) has a better foundation. Lukas and Clutton-Brock make a very clear point to state that a high risk of male infanticide is a consequence of social monogamy, rather than a cause. Furthermore, their data collection and analysis deals mainly with mating patterns over generations, where as Opie et al deal with other behaviors associated with males and females. Where social monogamy is primarily a behavior associated with mating, Lukas and Clutton-Brock make a more compelling argument as their data is more closely related to the topic at hand. With that, these two articles opened my eyes to the lack of a concrete reason behind social monogamy. There are clearly advantages to the different types of mating patterns, yet there is no agreed-upon reason as to why one, specifically monogamy, first started. This surprised me, as usually evolutionary changes can have a clear advantage, but in this situation, there is no primary and clear reason.