Humans have been ranked 7th out of 35 mammal species in a new Cambridge University study measuring monogamy. The ranking was based on genetic data comparing how often siblings share both parents — an indicator of pair bonding. Humans showed 66% full siblings, placing us among the most monogamous mammals.
However, we were beaten by species including Eurasian beavers and moustached tamarins, while meerkats and gibbons ranked just below. At the bottom were chimpanzees, dolphins and mountain gorillas, reflecting far more promiscuous mating systems.
Researchers say humans are unusual in the animal world for evolving towards monogamy, potentially linked to the rise of paternal care. Still, cultural pressures, religion and social norms play a large role, and many societies tend toward serial monogamy rather than lifelong pairing.
So humans are considered largely monogamous — just not as loyal as beavers.
