Helping Older Cheetahs Become Moms

If you’ve been paying attention to the goings-on at the Smithsonian Institution, you probably noticed the baby boom at the National Zoo. And one of the biggest success stories is that of the cheetah Amani, who gave birth to five cubs on May 28.

But the rest of her species isn’t doing so well. The wild cheetah population numbers only about 7,500 to 10,000 individuals (an 85 percent decline since 1900) and the captive population has had a tough time having babies. Amani’s litter will be the only captive-born cheetah litter from any North American zoo this year, and 80 percent of captive cheetahs die without producing any offspring.

Scientists are hopeful that may change, though. A new study, published in the Biology of Reproduction and led by researchers at the Smithsonian Conservation Biology Institute, examined the eggs, hormones and uteruses of 34 captive female cheetahs. They found that once the cheetahs had reached about eight years of age, they still produced normal eggs but there were problems with their uterine tracks that would prevent pregnancy.

“We were relieved to find that, unlike in other older mammals, the eggs in older cheetahs can produce viable-appearing and growing embryos, which means we may be able to transfer them to younger cheetahs and preserve genetic diversity,” says the study’s lead author, Adrienne Crosier of the SCBI. Preserving genetic diversity is a prime concern of any breeding program, because inbreeding can contribute to higher numbers of deaths among young offspring as well as lower disease resistance.

SCBI scientists may try an embryo transfer within two years, Crosier says. And other scientists are already thinking about how to use this research to include eggs from wild cheetahs in the captive breeding program.

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Sarah Zielinski | | READ MORE

Sarah Zielinski is an award-winning science writer and editor. She is a contributing writer in science for Smithsonian.com and blogs at Wild Things, which appears on Science News.