World

Zoos attempt to brace against the threat of species extinction

Some orangutans, like this one, have been released into the wild. But as habitats disappear, reintroduction could become nearly impossible.
Some orangutans, like this one, have been released into the wild. But as habitats disappear, reintroduction could become nearly impossible. The Associated Press

In the world of the old Hollywood movie “Hatari!” when zoos wanted exotic animals, they simply placed their orders and adventurers went out to scoop them up.

The savannahs and the jungles teemed with animals that had been around for ages.

But a half century later, instead of collecting new specimens, zoos try hard to keep the populations they have alive and reproducing.

The goal for species survival in captivity is just 100 years. That’s the hope. For most endangered species, even that’s iffy.

As the Kansas City Zoo prepares to open a new $6 million exhibit for its orangutans, conservationists are trying to build up genetic reservoirs for hundreds of animal species that are fast approaching the fate of the dinosaurs.

“Sumatran orangutans could be the first great ape to become extinct, and that could happen in the next 10 to 20 years,” said Zoo Atlanta’s Lori Perkins, the coordinator of the Orangutan Species Survival Plan. “That scares me really badly.”

Theoretically, keeping animals healthy in captivity means they could be reintroduced to the wild someday. But if an animal really disappears from the wild — because of poachers or people destroying its habitat — it’s a stretch to think we’d ever be able to send them back and make things good again.

“It doesn’t seem to be the talk of the town anymore,” said Kansas City Zoo director Randy Wisthoff. “When I started 38 years ago, that’s kind of what the talk was: We’ll reproduce in captivity and take it back out and set it free in its native habitat. But there’s getting to be less and less and less habitat. It’s going away.”

That raises the question of how long captive populations of endangered animals can be kept alive and genetically viable. One hundred years? Beyond?

Even if that works, how many generations distant from the wild will it be before the animals, even in the most lush and caring of zoo environments, begin to lose the natural traits that made them what they were? In other words, when does a captive orangutan cease to be an orangutan?

“I don’t know if anyone really knows,” said Kirk Suedmeyer, director of animal health at the Kansas City Zoo.

Threat of extinction

Left unchecked, biological diversity tends to increase. Genetic variations may lead to new species as evolutionary trees branch. But things seem to be going the other way. According to the International Union for Conservation of Nature, more than 16,000 species of animals and plants are threatened with extinction.

That includes one in eight birds, one in four mammals and a third of all amphibians.

The World Wildlife Fund’s Living Planet Index reports the population of vertebrate species declined by more than half in just 40 years.

In a paper published in the journal Science in January, 18 researchers warned that human civilization has already committed serious transgressions against the planet: deforestation, too much carbon dioxide in the air, excess nitrogen and phosphorous in the oceans — and the extinction rate of species.

More than half of the 633 known species of primates are in danger of going away. Lemurs, found naturally only on Madagascar, are said to be in their endgame. By one count last year, there were just 25 Hainan gibbons left on the only place they live, an island off China — and there are none in captivity.

There are thought to be only about 400 specimens left of the distinct subspecies of west African lion, and fewer than 250 of them are thought to be of breeding age.

Scientific American reported in December that the wild giraffe population dropped 40 percent in just 15 years, from an estimated 140,000 to about 80,000.

Endangered species range from the small and homely to zoo favorites, known in the trade as charismatic megafauna. It’s these zoo animals — the ones we find cute, majestic or vaguely human — that grab our attention.

Case study: orangutans

Orangutans exist, naturally, in two subspecies in just two places in the world: the Asian islands of Borneo and Sumatra.

But those places are hotspots for the production of the palm oil widely used in snack foods, soaps, cosmetics and a range of other products.

Old growth forests are chopped down for timber, and the land is then burned to make way for palm plantations. The results have been devastating. The Orangutan Conservancy estimates the apes lost more than 80 percent of their habitat in the last two decades. The Orangutan Foundation International estimates the total population has declined by 50 percent over the last decade.

Worldwide palm oil production doubled in the last decade, according to the World Wildlife Fund.

“The demand shows no signs of slowing,” reports the Orangutan Foundation International.

Pressure from conservationists led some high-volume purchasers of palm oil to take action. Yum Brands, which owns KFC, Pizza Hut and Taco Bell, has pledged to move toward suppliers that are not guilty of deforestation. Last month, McDonald’s followed suit. The Kansas City Zoo also has pledged to use palm oil products only from sustainable sources.

There is a scorecard that tells consumers which products contain palm oil from nonsustainable sources.

For now, orangutans continue to lose their forest home. Many are burned to death in the fires. Others are shot as they forage for food.

An estimated 6,500 Sumatran orangutans and about 54,000 Bornean orangutans remain in the wild.

Some 54,000 Bornean orangutans sounds like a lot. It’s not. They’re increasingly isolated from one another, reducing their chances of breeding and surviving.

“There are fewer and fewer ways for those individuals to connect to one another,” Perkins said. “They essentially live in islands on the island of Borneo.”

It doesn’t help that orangutans have long intervals between births, from six to 10 years.

“The slow reproductive rate of orangutans makes them especially vulnerable to extinction,” said Orangutan Foundation International. “As long as forests are being converted to other uses, there will be less available habitat for orangutans. Orangutans cannot survive without forests.”

The foundation continued: “Protecting forests and making it possible for orangutans to survive alongside human activity will be the only long-term solution for orangutan survival in the wild. Making this happen is easier said than done.”

Captive breeding

Not too many decades ago, zoos were indifferent about where their animals came from or if they bred successfully in captivity. If they died, zoos just ordered more from a contractor.

But shrinking populations and growing consciousness have resulted now in very few animal collections from the wild. Instead, zoos have turned to scientific management of their animals as the only practical option.

Maintaining genetic diversity is essential to that goal. The best tools are cooperative zoo agreements called species survival plans, or SSPs. Those “genetic lifeboats” rely on careful recordkeeping and management of breeding programs.

Zoos today rarely buy or sell animals. Instead, they share them to pair promising specimens and avoid inbreeding. That means some zoos house animals deemed inappropriate for breeding but still valuable for the education and entertainment of zoo visitors.

The Kansas City Zoo, for example, has two male Sumatran tigers. The zoo does not have a female because these two males are not now high on the list for breeding.

On the other hand, Kansas City once had several male lowland gorillas as part of an experiment in bachelor groupings. But coordinators of the gorilla SSP, constantly reassessing the captive situation, in recent years shipped some males out and assigned three females here. One, Makari from the Lincoln Park Zoo in Chicago, mated with a local male, Radi, and gave birth in 2013. The baby was premature and died. But Makari is pregnant again and due next month.

A 1986 study predicted that sustainable captive animal populations would have to last a dark age in the wild that could span 500 to 1,500 years. The SSPs have settled for a more realistic goal of just 100 years, but coordinators hope they can go on indefinitely.

The plans have had varying success. Ones that are considered sustainable for 100 years are labeled green. More iffy ones are called yellow. And the ones that need the most work are branded red. Only about 40 of the roughly 500 SSPs are considered green, said Candice Dorsey, director of animal programs for the Association of Zoos and Aquariums, which oversees the SSP program.

The orangutan SSP is green, with 87 Bornean orangutans, 85 Sumatran and 45 hybrids in North American zoos. The hybrids, which were born before it was realized that Bornean and Sumatran orangutans are distinct subspecies, are no longer bred.

“We are trying to grow both (Bornean and Sumatran) populations,” said Perkins of Zoo Atlanta. She has coordinated the orangutan plan for the last 30 years. “Our target is to have at least 90 to 100 individuals each. We’re close, but I would feel more comfortable having more births.”

The Kansas City Zoo has six Bornean orangutans in two separate groupings. Two successful births have occurred here since 2002.

Of the SSPs for four tiger subgroups — Sumatran, Amur, Malayan and generic — only the Amur is green, with 142 individuals in North America. The Sumatran plan, with 78 specimens in North America, would be considered green if the global captive population was counted. The Malayan SSP is considered yellow, with just 59 animals in North America. The 79 generic tigers are hybrids and are being allowed to die out to make room in zoos for genetically pure animals.

There are SSPs for three subspecies of rhino — the southern white, the eastern black and the Indian, or greater one-horned rhino. All three are considered yellow, which means they need more work.

“The (captive) populations are quite healthy and are fairly stable or growing,” said Steve Shurter, a rhino adviser to the AZA and director of conservation at the White Oak Conservation Center in Florida.

Reintroduction?

If captive populations can be sustained, at least a remote possibility exists that they could someday be returned to the wild. But that won’t be easy. Especially if the original habitat is gone.

“If we destroy Borneo, you’re not going to put Bornean orangutans in Russia or in Fiji,” said Suedmeyer. “You’re not going to create the island of Borneo again. If it’s gone, it’s gone.”

Some reintroduction efforts have had promising results.

Only 22 California condors were thought to be left in the early 1980s. Their numbers were decimated by loss of habitat and poisoning. A crash course of captive breeding and release has brought their numbers back to more than 400.

The black-footed ferret, indigenous to the North American West, remains one of the most endangered animals in the world, according to the U.S. Fish and Wildlife Service. The main reasons are loss of prey and habitat. But thousands of captive-bred ferrets have been released at two dozen sites since 1991, and the wildlife service reports that “the recovery of the species is within reach.” A new reintroduction proposal in Wyoming is currently in a 60-day comment period.

The scimitar-horned oryx, an antelope, was wiped out of its native scrubland in northern Africa in the 1980s, a victim of habitat loss, human conflict and sportsmen who killed them for trophies. A reintroduction effort was begun in recent years. Two oryx from the Kansas City Zoo were part of a herd reintroduced in Tunisia in 2007.

But reintroduction would be more complex for other species. It’s a lot easier for hoofstock like oryx to take hold in the wild than it would be for a big cat. The cats would have to learn to hunt.

“You cannot take large carnivores that have been raised by people and simply release them,” said Tara Harris, the coordinator of the tiger SSPs. “It’s a very long process.”

A plan to reintroduce Amur leopards, for example, will hinge on breeding the animals under semi-wild conditions and then releasing future cubs that have had almost no human contact.

Zoos are working with conservation efforts to help both wild and captive populations of some species. White Oak imported black rhinos from Zimbabwe in 1993 to start a captive breeding program. The Kansas City and Cleveland zoos also each imported female black rhinos from South Africa in the 1990s, and they both produced offspring.

“That was a real important importation at the time and bolstered the captive population,” Shurter said.

It goes the other way as well. The first black rhino calf produced at White Oak was sent back to a managed reserve in southern Africa and has since produced offspring.

If an attempt at large-scale reintroduction of a species becomes necessary, there is some concern whether captive animals — separated by generations from the wild — would retain the skills to survive.

One consideration in choosing which captive animals to breed involves how well adapted they are to human care. It is better to select for more feral traits and choose animals that are not as easy for zookeepers to work with.

“Part of genetic management is to retain as much of the animal’s footprint that it originally started with,” said Shurter. “We hope they will retain all of the characteristics they will need to go back.”

The authors of a 2009 report called “Sustaining the Ark” wrote pessimistically about the overall prospects for SSPs and the species they are meant to preserve. They concluded that only 48 percent were breeding at a rate to replace themselves. Just 55 percent had the genetic diversity to be considered sustainable.

“The Ark, it seems, is sinking,” the report concluded.

But Dorsey said progress is being made in many of the species survival plans.

“All the lines are going in the right direction,” she said.

The AZA on Friday announced a new initiative called SAFE, for Saving Animals From Extinction. Each year, the organization will focus effort and spending on 10 endangered species. This year, they include African penguins, Asian elephants, black rhinos, sea turtles and whooping cranes.

Kansas City Zoo director Wisthoff has hope for future conservationists and biologists who now, as children, will visit zoos and become inspired. Perhaps they will come up with better solutions for saving the world’s endangered animals.

“You can’t be a fatalist and do this,” he said. “You have to have hope.”

To reach Matt Campbell, call 816-234-4902 or send email to mcampbell@kcstar.com.

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