HUMANS are less likely to cheat than chimps – but are more prone to promiscuity than beavers.
They’re the findings of a major study into monogamy across the animal kingdom, which reveals the most and least faithful mammals.
And humans fared well in the research, ranking alongside meerkats for loyalty in love.
Top researchers at the University of Cambridge analysed the rate of “full siblings”.
That’s because species and societies that are very monogamous usually produce siblings that share both parents.
Counter to that, polygamous or promiscuous mating patterns tend to lead to more half-siblings, the scientists said.
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Based on that measurement, humans landed with a 66% “full sibling rate”.
“There is a premier league of monogamy, in which humans sit comfortably,” said Dr Mark Dyble, of Cambridge’s Department of Archaeology.
“While the vast majority of other mammals take a far more promiscuous approach to mating.
“The finding that human rates of full siblings overlap with the range seen in socially monogamous mammals lends further weight to the view that monogamy is the dominant mating pattern for our species.”
The researchers calculated human monogamy rates using genetic data from archaeological sites.
That includes Bronze Age burial grounds across Europe, and Neolithic sites in Anatolia.
They also looked at ethnographic data from 94 human socieites around the world, including “Tanzanian hunter-gatherers the Hadza, to the rice-farming Toraja of Indonesia”.
“There is a huge amount of cross-cultural diversity in human mating and marriage practices, but even the extremes of the spectrum still sit above what we see in most non-monogamous species,” Dr Dyble explained.
Meerkats ranked below humans with a 60% full sibling rate.
But beavers performed even better, coming in at a 73% rate for full siblings.
MONOGAMY RANKINGS – THE TOP 10
The most true and faithful revealed…
- 1. California deermouse – 100%
- 2. African wild dog – 85%
- 3. Damaraland mole rat – 79.5%
- 4. Moustached tamarin – 77.6%
- 5. Ethiopian wolf – 76.5%
- 6. Eurasian beaver – 72.9%
- 7. Humans – 66%
- 8. White-handed gibbon – 63.5%
- 9. Meerkat – 59.9%
- 10. Grey wold – 46.2%
Closest of all to humans was the white-handed gibbon, with a “monogamy rate of 63.5%”.
Interestingly, this gibbon was the only other top-ranked “monotocous” species – that means they typically have just one offspring per pregnancy, like humans.
Another high-ranking non-human primate was the moustached tamarin. The small Amazonian monkey typically produces twins or triplets, and earned a full sibling rate of 78%.
But other primates ranked far lower on the league tables.
Mountain gorillas came in with a paltry 6% full sibling rate, with chimpanzees ranking even lower at 4% – about the same as dolphins.
Macaques also ranked low, including the Japanese (2.3%) and Rhesus (1%).
The grey wolf and red fox both landed with middling rates of 46% and 45% respectively.
But Africa species had higher rates of monogamy, including the Ethiopian wolf (76.5%) and the African wild dog (85%).
MONOGAMY RANKINGS – THE BOTTOM 10
Here are the most promiscuous of the lot…
- 10. Bottlenose dolphin – 4.1%
- 9. Vervet monkey – 4%
- 8. Savannah baboon – 3.7%
- 7. Killer whale – 3.3%
- 6. Antarctic fur seal – 2.9%
- 5. Black bear – 2.6%
- 4. Japanese macaque – 2.3%
- 3. Rhesus macaque – 1.1%
- 2. Celebes crested macaque – 0.8%
- 1. Soay sheep – 0.6%
Top of the entire table is the California deermouse, which Cambridge scientists said stays “paired for life once mated”.
It had a strikingly high 100% full sibling rating.
And at the very bottom is Scotland‘s Soay sheep, which has a 0.6% rate.
Scientists say that this is because each ewe will mate with several rams.
“Almost all other monogamous mammals either live in tight family units of just a breeding pair and their offspring, or in groups where only one female breeds,” said Dyble said.
“Whereas humans live in strong social groups in which multiple females have children.”
He added: “This study measures reproductive monogamy rather than sexual behavior. In most mammals, mating and reproduction are tightly linked.
“In humans, birth control methods and cultural practices break that link.
“Humans have a range of partnerships that create conditions for a mix of full and half-siblings with strong parental investment, from serial monogamy to stable polygamy.”
The research published in the Proceedings of the Royal Society: Biological Sciences journal.
