Cheating on their partners is second nature to female cheetahs, which have been shown to be the most unfaithful of all the big cats.

Their promiscuity rivals that of the males and they will walk many miles to satisfy their desire for a second, third, fourth and even fifth mate for a single litter.

Female cheetahs are so determined to play the field that they will risk being killed by lions and hyenas in their search for mates. Their chances of catching sexually transmitted diseases also soar. But the risks are worth it because infidelity guarantees that their cubs are much more genetically diverse and it is thought to reduce greatly the chances of the young being killed by adult males.

A nine-year study, led by scientists from the Zoological Society of London, showed that almost half (43 per cent) of all litters contained cubs that had different fathers.

One litter of five cubs was thought to have been fathered by five different males. Three cubs definitely had different fathers, the fourth was probably fathered by another male and the fifth died before samples could be taken.

Infidelity among female cheetahs was identified by the genetic analysis of the litters in an area of the Serengeti National Park in Tanzania. Researchers collected samples of the animals’ droppings and extracted DNA to determine the genetic heritage of the cubs.

Dada Gottelli, of the zoological society, said: “Female cheetahs are the most unfaithful big cats. Before we started the DNA analysis, we thought it was possible that female cheetahs were choosing to be cheaters, but we were amazed by the level of infidelity that we uncovered.”

About 100 cheetahs, Acinonyx jubatus, live in the area where the survey was conducted but researchers discovered that many of the fathers were likely to live well beyond the study zone.

The finding overturns assumptions about the mating behaviour of female cats, which, apart from the domesticated species, are widely assumed to have a single male to father a litter. “In wild populations it is widely assumed that males are promiscuous while females are coy,” the researchers reported in the journal Proceedings of the Royal Society. “Our results indicate that female cheetahs are promiscuous, with high levels of multiple paternity.”

Male cheetahs will try to monopolise sexually receptive mates so, by being unfaithful,the females have devised a way to counter sexual harassment, the researchers concluded. But the strategy benefits the overall male population because it means that many more of them get the opportunity to mate and to pass on their genes to the next generation.

“It is assumed that a smaller proportion of males than females contribute to the gene pool owing to high levels of competition among males for mates,” the researchers said. “In a cheetah, a much higher number of males than expected contribute to the gene pool.”

They added: “Multiple mating could have primarily evolved as a deterrant to infanticide or to avoid sexual harassment. While female cheetahs are [sexually] receptive, males try to monopolise them. Our results demonstrate that males are often not successful in monopolising a female.”

Cheetahs are unusual in that the female has the larger terri-tory but this, the study suggests, makes it easier for them to escape the attentions of a single male and so find another mate. Equally, it is likely to reduce infanticide because males will be uncertain which cub is theirs.

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