Humans are playing in the premier league of monogamous mammals, according to a new ranking of animals by their reproductive habits, but we may need a new manager to beat the beavers.<\/p>\n
In the study from University of Cambridge, humans ranked 7th out of 35 species on the monogamy scale, pipping white-handed gibbons and meerkats, but lagging behind moustached tamarins and Eurasian beavers.<\/p>\n
Dr Mark Dyble, an evolutionary anthropologist at Cambridge, said humans sit comfortably in the top flight for monogamous species, but the vast majority of mammals take \u201ca far more promiscuous approach to mating\u201d.<\/p>\n
Animals in the lower ranks include feral cats, bottlenose dolphins and our close genetic relatives, chimpanzees and mountain gorillas. Scotland\u2019s Soay sheep is at the bottom due to each ewe mating with several rams.<\/p>\n
Scientists have reported rates of monogamy for human and animal populations before, but Dyble wanted to know where humans sat relative to other mammals. To do this, he analysed genetic data from animal and human studies and calculated the proportions of full versus half-siblings for each.<\/p>\n
Societies and animals with higher levels of monogamy tend to produce more siblings that share the same parents, while those with more promiscuous mating habits are likely to have a higher proportion of half-siblings.<\/p>\n
Dyble found that levels of monogamy varied substantially across more than 100 human populations he assessed. The lowest rate was seen at an Early Neolithic site in the Cotswolds where 26% of siblings were full siblings. Meanwhile, in four Neolithic populations in northern France, 100% were full siblings.<\/p>\n
He then ranked humans and 34 other mammal species by the average proportion of full siblings. The top 11, led by the California deermouse, are all considered to be monogamous, while the bottom 24 are regarded as non-monogamous species.<\/p>\n
Humans had a 66% rate of full siblings, meaning full siblings outnumbered half-siblings two-to-one. Beavers were ahead at 72% with meerkats just behind at 60%. Mountain gorillas came in at 6%, with chimpanzees and dolphins at 4%.<\/p>\n
Mammals such as chimpanzees were found to take \u2018a far more promiscuous approach to mating\u2019. Photograph: Nature Picture Library\/Alamy<\/p>\n