Zoos Focus on Breeding to Save Rare Animals : Ecology: From condors to poison dart frogs, vanishing creatures are being reproduced in conservation programs.

Zoos and aquariums, no longer mere display cases for nature’s creatures, are taking a more active part in efforts to preserve species that are rapidly disappearing from the wild.

The American Assn. of Zoological Parks and Aquariums, based in Bethesda, Md., coordinates a captive-breeding program for more than 50 endangered species at more than 150 zoos and aquariums.

“It’s not the same old zoo any more. It’s not the little guy with a mustache pushing a broom around,” said Dick George at the Phoenix Zoo in Arizona. “We have a responsibility to face up to in the next decade. It looks like we are going to be perpetual hosts to these animals.”

For example, in steamy cinder-block rooms next to the Rain Forest exhibit at the National Aquarium in Baltimore, curator Jack Cover directs the breeding of the blue poison dart frog.

Herpetologists at the aquarium in 1988 became the first to breed them. Success came after they spent five years carefully re-creating the frog’s natural environment, only to find the tiny creatures prefer the bottom of a plastic 2-liter soda bottle.

The progeny have never lived up to their name. Their parents were found in isolated pockets of jungle in Suriname, but the offspring have yet to produce the deadly poison that researchers want to study.

Many zoologists fear they may become curators of living museum pieces without a natural habitat to which to return. One of the main causes of species dying out has been habitat destruction. Illegal or uncontrolled hunting, pollution and predators introduced by man have also taken a toll.

“When you cut down a rain forest, you’re not just cutting down trees,” Cover said. “You’re cutting down the environment for thousands of species.”

To avoid extinction, an estimated 2,000 species of large invertebrates will need to be bred in the next two decades, said Michael Hutchins, director of science and conservation for the zoos and aquariums group. Only 900 species can be bred using the current facilities, he said.

“Space is extremely limited. Decisions we make now will probably doom some species to extinction and save others,” said Hutchins, who oversees the group’s Species Survival Plan. “The same kind of decisions will have to be made for wild animals.

“Some estimates are that a million species of animals and plants could go extinct in the next two decades. We don’t know what kind of impact that is going to have.”

Zoos may need to maintain captive populations for as long as 200 years, until human population can be stabilized and wild habitats restored, some biologists say.

In addition, zoologists in the future may have to move animals from place to place in the wild to maintain genetic diversity, and veterinarians may make “jungle calls” to keep wild populations healthy, Hutchins said.

“I tell people that zoos are going to have to change as much in the next 10 years as they have in the past 100, if they are to fulfill their role in conservation,” Hutchins said.

Animals bred under the Species Survival Plan must be members of endangered species that are numerous enough in captivity to afford a viable gene pool. To guard against inbreeding, computer records are kept of every animal and its lineage.

The aim of the program, which began in 1981, is to develop a self-sustaining captive population representing each species so that some of the animals can be reintroduced to the wild.

The Phoenix Zoo works with 14 species in the Species Survival Plan and has successfully reintroduced the Arabian oryx, similar to an antelope, to the deserts of Oman and Jordan. The Point Defiance Zoo in Tacoma, Wash., and the Wild Canid Survival Center near St. Louis have reintroduced red wolves in a North Carolina wildlife refuge.

The Philadelphia Zoo has bred the Guam rail, a small tropical bird that resembles a sandpiper. Cincinnati Zoo breeders implanted an Indian desert cat embryo into a surrogate mother--a domestic house cat. The cat gave birth to the cub and nursed it as if it were her own kitten.

At the aquarium in Baltimore’s redeveloped Inner Harbor (still one of the most polluted areas of the Chesapeake Bay) a collection of crickets, wax worms, fruit flies and other insects are kept in bottles on a shelf in a cramped, pungent work area behind the rain forest exhibit.

Blue poison dart frogs like is a diet high in calcium and phosphorous, humidity and privacy. The three-quarter-inch, blue-and-black frog is so-named because it secretes a deadly alkaloid similar to curare, which South American Indians use for poison darts.

“In the wild (frogs) lay their eggs under large jungle leaves,” Cover said. “We’ve found the bottom of 2-liter soda bottles are a real good breeding hut. We put a plastic leaf in a petri dish and put the bottle over the top.

“The male does a courtship dance. The female, if receptive, follows him in and does an elaborate courtship dance with all kinds of stroking and spinning. Then she lays her eggs and he’ll fertilize them.”

Cover and his colleagues are still working on how to get the frogs to produce the toxin. Herpetologists and others have tried several unorthodox methods.

Special diets didn’t work. Neither did daily handling of the frogs. They thought cold baths, to simulate the dangers of the wild, might be the key.

“We actually tested that hypothesis,” Cover said, “but in the wild the frog would already have to have the poison the first time a predator comes down. There wouldn’t be a second chance. So, danger doesn’t seem like it would stimulate production.”

Perhaps the most widely known of all rare animals is the California condor, largest land bird in North America. There are 40 California condors known to exist and all are in captivity--21 at the San Diego Wild Animal Park and 19 at the Los Angeles Zoo.

The last condor found in the wild was captured in 1987. Scientists had hoped to breed them both in captivity and in the wild, but between 1984 and 1985, four of the last five breeding pairs in the wild were lost and presumed dead. In 1985, federal officials decided to capture all remaining wild condors for a last-ditch effort to save the species.

That drew criticism from several environmental groups, but it appears to have been the right choice.

“When we first hatched birds in captivity, it was pretty exciting,” Dr. Michael Wallace, curator of birds at the Los Angeles Zoo, said. “We were under a lot of pressure from outside groups to release the birds. It’s good to see we could not only do it, but do it fairly well.”

Four of the vulture-like chicks were hatched this year at the San Diego park and four at the Los Angeles Zoo. That success has enabled zoologists to consider releasing some of the condors as early as next year, several years ahead of schedule.

Zoologists are quick to caution that breeding programs are only part of the solution, however.

“Zoos are looking at being part of a holistic program,” Hutchins said. “If we are going to save species, we just can’t save them in zoos--but at least having these populations in captivity provides us with the option of reintroducing them.”