Humans are among the most monogamous mammals, ranking 7th out of 35 species in a new Cambridge University study. By comparing the proportion of full siblings versus half-siblings across species, researchers found humans average 66% full siblings, placing us above meerkats and gibbons — but below Eurasian beavers, who scored 72%.
While humans show a strong tendency toward pair bonding, results varied widely across different populations, suggesting social and cultural factors play a big role. Most mammals are far more promiscuous, with chimpanzees and dolphins scoring near the bottom of the list.
Scientists believe human monogamy likely evolved alongside paternal care, offering advantages for raising offspring. Still, researchers note that humans often lean toward serial monogamy or polygamy when social pressures are removed.
So, we’re high in the standings — but the beavers still win this one.

