A new Cambridge University study places humans 7th out of 35 mammal species in a ranking of monogamy levels. Using genetic data to compare how many siblings share both parents, researchers found humans have 66% full siblings, putting us among the more monogamous mammals — though Eurasian beavers (72%) and several primates ranked higher.
Animals such as feral cats, dolphins, chimpanzees and gorillas showed far lower monogamy rates, with gorillas at only 6%. Despite close genetic ties to humans, these species have far more promiscuous mating systems.
Scientists suggest human monogamy may have evolved alongside paternal care, though cultural and religious pressures also play a major role in maintaining pair bonds. While humans sit comfortably among monogamous species, researchers note that true lifelong pairing — like in beavers — is far less common in reality.
