Seven endangered black-footed cats have been born this year in the United States, but Crystal is the rarest — the first ever born from an embryo fertilized in a lab dish, frozen, and later implanted in a housecat's womb.
"Wow! That's so very cool," said Steven Wing, the American Zoo Association's species survival plan coordinator for black-footed cats, Africa's smallest wildcat and one of the world's smallest felines.
He had learned of the birth Feb. 6 at the Audubon Center for Research of Endangered Species, but not that a different species had been the host mother.
Wing said black-footed cats, which usually have one or two kittens per litter, also gave birth this spring at zoos in Omaha, Chicago, and Birmingham, Ala. Together with Crystal, born Feb. 6 at the Audubon Center for Research of Endangered Species in New Orleans, they bring the U.S. total to 60, he said.
At least two others are pregnant, "but I don't want to count my kittens before they hatch," said Wing, general curator at the Louisville Zoo in Kentucky.
Crystal is cute, with a pink button nose and large round eyes. But even as a tiny, fubsy kitten, a black-footed cat is fierce.
The kitten is also proof that embryos of this dwindling wild species can be successfully implanted into domestic cats, a different species — and that more work is needed to successfully clone them. Cloning would let scientists create embryos from carefully preserved dead animals.
Only an estimated 10,000 of these cats, which get their name from their distinctive black foot pads, still live in the wild. But they're "so nocturnal and so secretive, nobody knows how many are out there. We do know they're very, very rare," Wing said.
Crystal has two brothers, born a year ago. They also are test-tube kittens, but their host mother was a black-footed cat rather than a housecat.
In Africa, the population of black-footed cats is declining because of loss of habitat to grazing and farmland, and dwindling numbers of rodents and ground-nesting birds they hunt. The International Union for Conservation of Nature and Natural Resources lists the species — which grow to only about a third of the size of domestic cats — as vulnerable to extinction. The U.S. Fish and Wildlife Service considers them endangered.
ACRES has been working since it opened in 1996 to preserve endangered cats using advanced methods such as cloning and test-tube fertilization.
Both Crystal and her two brothers grew from embryos created in 2005, using sperm collected and frozen two years earlier at the Henry Doorly Zoo in Omaha, Neb., and eggs from a female housed at ACRES.
Because black-footed cats are so rare, it's not always possible to have one in the right biological condition to be a host mother, said Earle Pope, interim director at ACRES. And even if it were, it makes more sense to have any dangers of pregnancy borne by a common housecat than an endangered wildcat.
Page 2 of 2 - ACRES has successfully cloned three other wildcat species, using domestic cats as host mothers for the two species small enough for their wombs.
Cloned black-footed cat embryos never made it to term after being implanted in housecats, Pope said. "We're still trying to work out why that is the case."
Pope said Crystal's birth shows that the problem wasn't with using housecats as host mothers, but with the cloned embryos.
"We know that it can work if we put the right kind of black-footed cat embryo in there," Pope said.
Pope said keepers had hoped that Crystal might be used for outreach and education — given her surrogate mother is a domestic cat and the kitten sees people every day.
But she's just too wild, he said.
The same thing happened with Jazz — an in-vitro African wildcat born to a housecat in 1999. Although both species look a lot like housecats, their wild heredity was much stronger than their environment.
In the wild, black-footed cats — which can kill animals bigger than themselves — spend their days sleeping in burrows and hollow termite mounds in southern Africa, and their nights hunting. They grow to about one-third the size of the average domestic cat.
"Because they're so tiny, I guess their defense mechanism is to appear to be as ferocious as they can for their size," Pope said.