A new Cambridge University study has attempted to settle an age-old question — just how monogamous are humans? According to researchers, humans sit 7th out of 35 mammal species, placing us firmly in the monogamous tier, though still behind champions of loyalty such as Eurasian beavers and moustached tamarins.
The ranking, led by evolutionary anthropologist Dr Mark Dyble, compared the proportion of full siblings to half-siblings in more than 100 human groups and dozens of animal populations. The logic is simple: the more full siblings, the more monogamous the species. Humans reached an average 66% full siblings, compared with 72% in beavers. Meerkats trailed closely behind humans at 60%.
At the bottom end of the scale were chimps, dolphins and gorillas, where promiscuity or polygynous group structures mean half-siblings are far more common. Soay sheep ranked last.
While humans show strong monogamous tendencies compared to most mammals, researchers note that culture plays a major role. Some societies historically showed near-total monogamy, while others leaned toward serial partnerships or polygamy depending on religion, social norms and environment.
Experts suggest monogamy in humans may have evolved as a survival strategy: either confuse paternity through promiscuity or create certainty so males help care for offspring. Humans, unusually, took the latter route.
So while we may not top the championship — beavers currently hold the crown — humans are firmly placed in the upper league of mammalian monogamy.
