Playing God, and Noah, at Zoos

By Frederic Golden

Increasingly, they must not just exhibit, but also save and breed

At 7,000 Ibs., she was not Dr. David Gershuni's everyday kind of patient. But the orthopedic surgeon, working early one morning in a large barn at the San Diego Wild Animal Park, was unfazed by his jumbo task: to place a cast around the fractured leg of a twelve-year-old African elephant named Mandavu.

Mandavu had tumbled into the moat around her compound one night and broken two bones of her lower right rear leg. When the leg did not heal, it seemed that Mandavu might have to be put out of her misery--even though she was in the twelfth month of a 21-month pregnancy. So zoo officials decided on an operation that had been performed only once before.

It was, well, an elephantine undertaking. Mandavu had to be properly fettered, so she could be easily anesthetized with an injection in the rump. Her keepers also had to make sure that when she went to sleep she slumped over on her left side, to expose the injured right leg. Finally, everything had to be done quickly; if Mandavu were kept anesthetized too long, she might suffocate under her own weight.

Assisted by some 20 people, Gershuni first made an incision in the elephant's tough skin just below her knee, using a foot-long saw instead of a scalpel. Then, with an electric drill, he cut a hole through one of the fractured bones and shoved in a 12-in.-long steel pin; this served as an anchor for the heavy hoof-to-knee cast. Three and a half hours later Mandavu was brought back to consciousness. Within GARRISON minutes she lumbered to her feet, apparently no worse for the experience.

It will be months before the zookeepers can tell if the fracture has healed, but Mandavu seems to have accepted the massive cast, and her pregnancy remains normal.

Mandavu's misfortune is not uncommon at the 1,800-acre Wild Animal Park and sister San Diego Zoo, which together house 6,500 animals of 1,050 different species. In a typical month, dozens of them wind up on the sick list as a result of diabetes, birth complications, infected teeth, or any one of a score of other problems, including injuries from fighting.

Replacing such animals, at a time when they are increasingly endangered in the wild, is almost impossible. Says Pathologist Kurt Benirschke, the San Diego Zoo's director of research: "Five years ago, if a tiger died, you paid $2,000 and bought a new one. You can't do that any more." So zoos find themselves assuming a new responsibility. Besides exhibiting animals, they must keep ailing ones like

Mandavu alive and, even more important, breed rare varieties. Says William Conway, head of the New York Zoological Society: "More species are going to have to be sustained in captivity if they are going to survive at all."

Breeding raises serious ethical questions. Which species should be selected for such programs? And how can problems of genetic inbreeding be avoided in limited zoo populations? In September, the American Association of Zoological Parks and Aquariums set up a "species survival" program to deal with such issues. Warns Conway: "If zoos are going to function as an ark, it's going to have to be a rather exclusive ark."

Though zookeepers may not like to play God, or even Noah, they are already doing that in a modest way. Among the animals successfully bred at the Bronx Zoo are Przewalski's horses, a wild species now believed to be extinct in its native Mongolia; Pere David's deer, which vanished from China around the turn of the century; and the European bison, only recently reintroduced into Poland, where the last wild one was killed in 1921.

As would-be panda breeders have learned, getting animals to breed in captivity is not always easy. Sometimes Mother Nature must be fooled. At the Bronx Zoo, ornithologists have induced cranes and puffins to begin laying eggs earlier in the season by installing large floodlights that make the birds think spring has arrived. They have also sped up the Andean condor's usual lethargic reproduction rate of one chick every two years, by snatching away the eggs soon after one is laid and incubating it so that the mother is free to lay more eggs.

Perhaps the bravest new world technique involves the Bronx Zoo's herd of gaur, large wild cattle from southern Asia. By treating a female with hormones, the zookeepers got her to produce more than her usual number of eggs. After fertilization the embryos were removed and implanted in domestic cows, which are now acting as surrogate mothers. If the experiment works, it will be the first time different species have been successfully transplanted into domestic cattle.

San Diego Zoo scientists are pondering a long-distance scheme whereby their Siberian tigress would be fertilized by sperm from a male Siberian in Hamburg. Her eggs might then be implanted in various lionesses, leaving the tigress free to produce several litters a year. Such experiments could be aided by computerized stud books being produced by a program dubbed ISIS (for International Species Inventory System), which has compiled lists of animals at some 130 zoos.

Still, at times, old-fashioned methods work best. The Bronx Zoo has produced six baby gorillas through ordinary mating, encouraged partly by surrounding prospective fathers with lovelies--three or four females for every male. Conway notes with pride that male gorillas from the Bronx on loan to other zoos "have achieved a certain reputation as studs."

Other zoos are pushing their own breeding efforts. At the London Zoo last summer, a baby puma named Bonny was born via artificial insemination to a mother rendered receptive by hormone injections. Although Bonny made history as the world's first artificially bred big cat, many Britons found the event to be decidedly unblessed. In a letter to the London Times, one complained bitterly: "No matter how near extinction they may be, there can be no excuse for maintaining the race alive in a glass case." But zoo officials see the birth as a first step toward the widespread artificial propagation of endangered breeds of big cats.

Besides restocking animals for display, some zoos hope such breeding experiments can provide the basis for new populations in protected habitats. The London Zoo has already helped put zoo-bred chimpanzees into the forests of Gambia, where they seem to be surviving. Several of the Bronx Zoo's condors now dive and wheel over the mountains of Peru. One of the most prestigious breeding programs has been established on the island of Jersey in the English Channel, where a British group under the honorary directorship of Biologist-Author Gerald Durrell has been breeding everything from rare primates (lemurs and marmosets) to endangered birds (the brown-eared pheasant and thick-billed parrot) and reptiles (the red-footed tortoise and Jamaican boa).

Perhaps the ultimate protection against species extinction is what the San Diego scientists call their Frozen Zoo. More than just a sperm bank, it is a repository of fibroblast cells taken from the connective tissue of hundreds of exotic wild animals, ranging from Sumatran tigers to Uganda's pygmy chimps. These cells, which are easier to store and grow than most, are kept in liquid nitrogen at a temperature of --196DEG C ( -- 320DEG F) against the day when technology will be ready to reawaken them. Says San Diego's Benirschke: "We could probably get along all right without the rhino, and we're doing all right without the dodo. But do we want to have a world with just cats, dogs, sheep, cattle, chickens and sparrows?"

-- By Frederic Golden

Reported by Erik Amfitheatrof/ London and Diane Coutu/ San Diego

With reporting by Erik Amfitheatrof, Diane Coutu

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