tags: cheetahs, evolution

DNA technology has revealed that female cheetahs, Acinonyx jubatus, often produce litters that are comprised of cubs sired by multiple fathers. This research, recently published in the Proceedings of the Royal Society B, studied cheetahs found on that part of the Seregeti in the African nation, Tanzania.

“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 research team.

However, infidelity could also expose the mother cheetahs to disease.

Although infidelity is unusual for most big cat species, DNA analysis of fecal samples from 176 individual cheetahs showed that, of 47 litters of cubs studied, 43% were comprised of cubs sired by multiple fathers. In some cases, three different males were responsible for the cubs of just one litter. But the scientists think this is an underestimate.

“Cheetah cubs suffer high mortality on the first few weeks so it was difficult to get samples from all of them,” Gotell said.

Cheetahs are unusual among mammals because the females are solitary and have large home ranges whereas the males form coalitions that occupy small territories that comprise less than 10% of the females’ home ranges. Female cheetahs successfully breed with multiple males because they produce a new egg each time they mate, a process known as induced ovulation.

It is thought that cheetah promiscuity must provide an evolutionary benefit to the species that offsets the associated risks to the female from predation, parasites and disease. For example, because the effective breeding population for wild cheetahs is estimated to be less than 10,000 individuals, induced ovulation and mating with multiple males can lessen potential inbreeding problems. This increased genetic diversity among the resulting cubs can allow them to more readily adapt to change. However, it may also protect the cubs from wandering males.

“Infanticide has not been observed in the wild cheetahs, like it has been in lions and leopards,” noted 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.”

Sources

Genetic analysis reveals promiscuity among female cheetahs by Dada Gottelli, Jinliang Wang, Sultana Bashir and Sarah M. Durant Proc. R. Soc. B doi:10.1098/rspb.2007.0502 [abstract and entire article; PDF]

BBC News (quotes, image)