Cheating cheetahs caught by DNA

By Jonathan Fildes
Science and technology reporter, BBC News

Infidelity is not common among other big cats Enlarge Image

The female cheetahs that prowl the Serengeti in Tanzania appear to live up to their name, scientists have shown.

DNA analysis of the spotted cats found that they were serial cheaters, with nearly half of their litters made up of cubs from different fathers.

Writing in Proceedings of the Royal Society B, the scientists say the infidelity may expose them to disease.

However, it could also ensure the genetic diversity of the endangered species, the researchers hypothesise.

"If the cubs are genetically more variable it may allow them to adapt and evolve to different circumstances," Dada Gottelli of the Zoological Society of London (ZSL) and one of the scientists on the study told the BBC News website.

"If there is a big change in the environment some may be able to cope better."

Paternity test

Cheetahs (Acinonyx jubatus) are classified as a vulnerable species according to the World Conservation Union (IUCN).

The effective breeding population is estimated to be below 10,000 individuals and the species faces threats including habitat loss and poaching.

The new research tracked known cheetahs in the Serengeti National Park in north-west Tanzania over nine years.

Analysis of DNA collected from the faecal samples of 176 cheetahs showed that infidelity was rife, although uncommon in other big cats.

Researchers tracked the cheetahs for nine years. Enlarge Image

Of 47 litters of cubs, 43% contained cubs from multiple fathers. In some cases, three males were responsible for the cubs of just one litter.

"If anything, this is an underestimate," said Ms Gotelli. "Cheetah cubs suffer high mortality on the first few weeks so it was difficult to get samples from all of them."

Female cheetahs are able to successfully mate with multiple males as they produce a new egg each time they mate, a process known as induced ovulation

Common in domestic cats and other species such as rabbits, it means that each egg can in theory be fertilised by sperm from a different male.

The high incidence of promiscuity among females coupled with the fact that they increase their risk of predation, parasites and disease to mate with multiple males suggests that there must be a benefit to the behaviour.

The researchers believe the evolutionary pay-off is increased genetic diversity, allowing some of the cubs to more readily adapt to change.

This is good news for conservationists trying to preserve the threatened species as small populations of animals can face problems of inbreeding.

However, the duplicitous behaviour may also bring other benefits such as protecting the cubs from marauding males.

"Infanticide has not been observed in the wild cheetahs, like it has been in lions and leopards," said Ms Gotelli. "Maybe this is why.

"It may create confusion in the males. In that case it's better not to kill any cubs in case they were yours."