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Extinction Countdown

Extinction Countdown

News and research about endangered species from around the world

Rare African kittens bred from frozen eggs and sperm

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One of the risks in writing about endangered species is concentrating too much on the cute ones. But I couldn't skip covering the African black-footed cat (Felis nigripes) and the scientific breakthrough that could give this rare species an extra chance at survival.

The African black-footed cat is one of the world's smallest and rarest cat species, not to mention one of the least studied. Full-grown cats, native to southern Africa, weigh just 1.3 to 1.9 kilograms and have a body length of about 36 to 63 centimeters, not including the tail. The species, listed as vulnerable to extinction on the International Union for Conservation of Nature and Natural Resources Red List of Threatened Species, has a shrinking population—fewer than 10,000 individuals—and has only been studied once in the wild.

The cat is even rarer in captivity than it is in its native habitat. Until a month ago only 40 of the cats were in zoos worldwide, 19 of which are in the U.S.

Now there are two more of these cats in captivity: Two male kittens born at the Audubon Center for Research of Endangered Species in Algiers, La., were produced via in-vitro fertilization using frozen eggs and frozen sperm, a scientific first.

The sperm was originally collected in 2003 from a male cat named Ramses living at Omaha's Henry Doorly Zoo's Center for Conservation and Research. The eggs came from a black-footed cat named Zora that lived at the Audubon center and were collected in March 2005. The fertilized eggs were implanted into a third cat, named Bijou, on December 7, 2010, and the kittens were born on February 13.

One of the goals of the project was to prove that the eggs and sperm could survive an extended freezing period.

Lead scientist Earle Pope says there were several factors that affected the project, most notably Hurricane Katrina, which hit the region in 2005. Zora, the egg donor, left Louisiana for Omaha in June 2009 and died later that year. Audubon did not acquire additional females until 2009 and 2010. "After the hurricane we did not resume our assisted reproduction work with black-footed cats until 2008, and then we did only a couple of procedures before increasing our activity in 2010 after being fortunate enough to obtain the young females," Pope says.

Bijou herself, born in September 2008, has not yet produced enough of her own eggs to work with in assisted reproduction research. This is her first birth.

The kittens have spent most of their time so far with their surrogate mother. "We did not examine or handle the kittens until they were 15 days old," Pope says, "at which time they weighed 156 and 198 grams." They were weighed again at 26 days, at which time they had grown to 274 and 308 grams, respectively.

The Audubon program aims to further the science of preserving cells from endangered species for use when wild populations crash. "We don't know what the future holds for many of these species," the center's director, Betsy Dresser, said in a prepared statement. "But we do know that by preserving DNA and working on protocol[s] for creating pregnancies and producing babies through cryopreservation and surrogate mothers, we are giving these species a shot at survival even when their numbers dip to dangerously low levels."

The next step in Audubon's research will be to clone a black-footed cat and transfer the egg to a domestic cat surrogate.

By the way, these kittens may be cute, but the adult felines are actually quite formidable. African folklore says they can rip the jugulars out of giraffes, and while the truth doesn't bear up to the myth, the cats have been observed stalking small lambs and holding their own against jackals eight times their size. That may not protect them from the threat of habitat loss, but at least they (and the scientists at the Audubon Center) are willing to fight for their survival.

 

Photo: One of the black-footed kittens, courtesy of Audubon Center for Research of Endangered Species

The views expressed are those of the author and are not necessarily those of Scientific American.

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