Humans Rank Among Leading Monogamous Mammals

A recent study conducted by researchers at the University of Cambridge has positioned humans as the seventh most monogamous species among 35 mammals, according to their reproductive habits. The findings, published in the *Proceedings of the Royal Society B*, reveal that humans have a 66% rate of full siblings, indicating that full siblings outnumber half-siblings by a ratio of two-to-one. This places humans behind species such as the Eurasian beaver, which has a 72% rate, and moustached tamarins at 77.6%.

The Guardian

Dr. Mark Dyble, an evolutionary anthropologist leading the research, analyzed genetic data from over 100 human populations to determine the proportion of full versus half-siblings. This analysis highlighted significant variability in monogamous practices across different societies. For instance, an Early Neolithic site in the Cotswolds showed only 26% of siblings as full siblings, while four Neolithic populations in northern France exhibited a 100% rate.

The Guardian

The study categorized mammals based on their monogamous tendencies, with the California deermouse leading at 100% full siblings, followed by the African wild dog at 85% and the Damaraland mole-rat at 79.5%. In contrast, species like chimpanzees and bottlenose dolphins exhibited much lower rates of monogamy, with chimpanzees at 4% and mountain gorillas at 6%.

The Guardian

The evolution of human monogamy is a subject of ongoing debate among anthropologists. Dr. Robin Dunbar from the University of Oxford noted that humans exist on the cusp between monogamous and polygamous species, suggesting that social and religious pressures often dictate monogamous relationships. He warned against conflating human desires for polygamy with the realities of social constraints that promote monogamy.

The Guardian

Dr. Kit Opie from the University of Bristol offered an alternative perspective, proposing that both promiscuity in chimpanzees and monogamy in humans may serve as strategies against male infanticide, a significant risk in large-brained primate species. This theory posits that females may either confuse paternity through promiscuity or ensure paternal investment through monogamous pairings.

The Guardian

The study's results contribute to a broader understanding of human reproductive strategies and their evolutionary underpinnings. By situating humans within the context of other mammals, researchers can better explore the complexities of human relationships and the factors influencing monogamous behavior.

The Guardian

• “There’s a risk here of confusing desire with reality: humans desire polygamy but are constrained into a grudging form of monogamy by social or religious threat.” — Dr. Robin Dunbar, Professor of Evolutionary Psychology

The Guardian

The ranking of humans among monogamous mammals sheds light on the intricate dynamics of human relationships and the evolutionary factors that may have shaped them. As research continues, understanding these patterns may provide deeper insights into the nature of human mating systems and their implications for societal structures.

The Guardian