A new Cambridge University study has placed humans 7th out of 35 mammal species for monogamy, ranking above meerkats and gibbons but behind species such as Eurasian beavers and moustached tamarins.
Researchers analysed genetic data to compare how often siblings shared both parents, finding humans averaged 66% full siblings, while beavers reached 72%. At the bottom of the list were highly promiscuous species like chimpanzees, dolphins and mountain gorillas.
The study shows humans evolved an unusually strong tendency toward pair-bonding compared with most mammals, though social pressures, religion and serial monogamy still shape modern behaviour.
Scientists say the real puzzle is why humans became monogamous at all — especially given our closest relatives are not.
