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Scientists Race Against Time to Save Fastest Creature Afoot : Cheetahs: The cats are vanishing from the wild and do not breed well in captivity. Studies and laboratory projects seek to replenish their numbers.

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SMITHSONIAN NEWS SERVICE

Dr. JoGayle Howard watched and waited patiently as a 5-year-old female cheetah at a Florida research facility wobbled a bit, then wobbled some more and finally fell over. The dazed and drowsy cheetah, shot earlier with an anesthetizing dart, was asleep within another minute or so.

Howard, a postdoctoral fellow at the Smithsonian’s National Zoological Park in Washington, D.C., and her colleagues had been waiting for that moment. They quickly loaded the cheetah onto a truck and drove her to the hospital at White Oak Plantation in Yulee, Fla., a private center for breeding rare animals. There, a team of veterinarians, reproductive physiologists and zookeepers surgically removed eggs from the cheetah’s ovaries, placed them in a laboratory dish and added sperm taken earlier from a male cheetah.

Howard and her colleagues were seeking to determine whether that male could father offspring, and also to develop new methods for breeding cheetahs. “We want to know which cheetahs can breed in captivity and how that influences their behavior,” she said.

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Their work is part of an effort by zoos in the United States and elsewhere to help save the cheetah from extinction and to learn more about this mysterious wild cat.

Capable of running 70 m.p.h., the cheetah is the world’s fastest land animal. Once common throughout the grasslands of Africa and Asia, most are now found in eastern and southern Africa, although some may still roam northern Iran.

No one knows how many wild cheetahs remain, said Dr. Tim Caro, a wildlife biologist at the University of California at Davis. Caro puts their population at between 5,000 and 25,000, the range reflecting the uncertainty of the estimates. Whatever the number, most researchers and conservationists agree it is falling. In Namibia in southwestern Africa, for example, cheetahs have declined in number to about 2,500 from about 6,000 in 1980.

Probably never very numerous, cheetahs have been losing habitat as farms and ranches are carved out of the wild to feed Africa’s burgeoning human population. In many areas, cattle and other livestock have replaced the small, fast gazelles on which cheetahs prey.

When cheetahs turn their attention to domesticated animals, ranchers often shoot the big cats. Even in protected areas, such as Tanzania’s Serengeti National Park, cheetahs have dropped in number from 250 in the mid-1970s to about 60 today, probably because cheetahs are losing the race for survival to lions and other stronger predators.

The plight of cheetahs in the wild gives a sense of urgency to efforts to breed them in captivity, said Laurie Marker-Kraus, former director of the National Zoo’s New Opportunities in Animal Health and Sciences center and now co-director of the Cheetah Conservation Fund, a conservation group based in Namibia.

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“We have to save their habitat in Africa first,” she said, “but we also have to establish self-sustaining zoo populations.”

Indeed, until recently, cheetahs were difficult to breed. None reproduced in a zoo until 1956, and no zoo-born cub survived more than a few days until 1960. No second-generation, captive young were produced until 1976.

Today, there are about 235 cheetahs in U.S. and Canadian zoos and 600 others elsewhere, Marker-Kraus said. Although three-fourths of those were born in captivity, zoo deaths still outnumber births, partly because of a deadly viral disease that strikes all cat species.

High infant mortality is often a hallmark of an inbred animal species, researchers say. In North American zoos in 1990, for instance, 125 cheetahs died and 131 cubs were born. Nearly a third of those cubs have since died.

Not all cheetahs will breed in captivity. Fewer than half of all captured cheetahs have reproduced in zoos, Marker-Kraus said. Last year, cubs were born in just eight of the 32 U.S. and Canadian zoos that have cheetahs.

Several years ago, Dr. Stephen O’Brien, Dr. David Wildt and Dr. Mitchell Bush thought they knew why cheetahs don’t breed well in zoos. Wildt and Bush, who are chief reproductive physiologist and veterinarian, respectively, at the National Zoo, discovered that cheetah sperm counts average 70% abnormal, usually enough to consider a domestic animal infertile. And O’Brien, a geneticist at the National Cancer Institute in Frederick, Md., found almost no genetic diversity in captive or wild cheetahs, which could explain the sperm abnormalities, he said.

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Without disputing those findings or their significance, other researchers say several factors may affect cheetah breeding. To find out, U.S. and Canadian zoos decided to consider their cheetahs one population for research and breeding purposes. The zoos launched a cooperative effort to learn more about the animals and to improve their birth rate in captivity. The zoo program includes behavioral, physiological, medical and nutritional studies and is part of a cheetah Species Survival Plan administered by the American Assn. of Zoological Parks and Aquariums of Wheeling, W. Va.

At the San Diego Wild Animal Park, animal behaviorist Dr. Donald Lindburg said that cheetah sexual problems lie with the females, not the males. Not all females come into heat, he said, and estrus “is not conspicuous in cheetahs. If we stand there waiting for some sign, we may miss it.”

With that in mind, three days a week the San Diego Wild Animal Park lets its male cheetahs go through the enclosures of females, which have first been removed. (Because cheetahs are usually solitary animals, zoos keep males and females apart, except when breeding.) At San Diego, if the male begins to stutter-bark--a sound males make when sexually aroused--or look for the female, she is put back into the enclosure to mate.

So far, the results are encouraging. San Diego, which recorded 90 cheetah births between 1970 and 1980 and 60 births since 1981, has had five first-time breeders produce offspring since last summer. “The males are much better at detecting a female in estrus than we are,” Lindburg said.

Beginning this summer, the University of California’s Caro and a graduate student will examine cheetah behavior at the zoos in San Diego and Columbus, Ohio. They will look at housing conditions, existence of raised platforms for viewing surrounding exhibit areas, proximity of other large predators and ability to choose a mate as potential factors in whether individual cheetahs breed in captivity.

At the same time, Paule Gros, another student of Caro’s, will survey government officials, wildlife biologists, conservationists and local people in eight African countries. Through written questionnaires and interviews, Gros will seek to learn where cheetahs live, whether there are trends in their population, what problems they face and what conservation measures are needed to protect them.

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Meanwhile, Wildt and graduate student Ann Donoghue are surveying the health and reproductive status of all cheetahs in U.S. and Canadian zoos. Using a mobile laboratory crammed with sophisticated equipment, they travel from zoo to zoo and examine the cheetahs to check their reproductive organs and hormone levels and to collect sperm and ova.

The National Zoo researchers have also begun to inseminate cheetah ova in the laboratory to learn which males are fertile. In addition, they have learned that some males with abnormal sperm counts can father test-tube embryos. The researchers have implanted fertilized ova in females, a technique that has produced viable pregnancies in tigers and domestic cats. If successful in cheetahs, it could be used to increase the number of breeding males, Howard said.

“We are building the most comprehensive database ever on the health and reproductive biology of an endangered species,” Wildt said. “We will be able to identify why some cheetahs reproduce and others do not.”

In the end, getting cheetahs to breed in zoos and protecting them in the wild will depend on what is learned through these and other research projects, Marker-Kraus said.

Much will depend on personal commitment as well. “This is not a 9-to-5 job,” she added. “We will have to be very well tuned in to the animals and their needs.”

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