A new University of Cambridge study has ranked humans 7th out of 35 mammal species for monogamy, placing us among the most pair-bonded animals. Humans showed a 66% rate of full siblings, indicating mostly two-parent households, sitting just behind Eurasian beavers (72%) and ahead of meerkats (60%) and gibbons.
At the bottom end are highly promiscuous species such as chimpanzees, dolphins, and mountain gorillas, which scored just 6%.
Researchers analysed genetic data to compare how often siblings shared both parents across species. While humans rank as largely monogamous, experts note that culture plays a major role — with serial monogamy and polygamy still common when social constraints are relaxed.
The results highlight how unusual human mating patterns are compared with our closest relatives, and raise questions about why monogamy evolved in humans at all.
