Lions, tigers, big cats may face extinction in 20 years

— -- Icons of the wild — lions, tigers and other big cats — are fading from the world's wild places, warn conservation experts worldwide.

Their plight was overshadowed by last week's release and subsequent killing of captive big cats, including Bengal tigers and African lions, from a private preserve in Zanesville, Ohio. Kin living in the wild have dramatically worsened: Wild lions, tigers and other big cats may face a slide toward extinction within two decades, say conservation scientists, who are urging increased efforts to save them.

"Do we want to live in a world without lions in the wild?" says Duke University biologist Luke Dollar of the National Geographic-sponsored Big Cats Initiative (BCI), which seeks emergency conservation steps worldwide. "That is the choice we are facing."

The populations of lions, leopards, cheetahs and especially tigers have been decimated in the past half-century. Tigers have become so rare that lions have become their soup-bone substitutes, sought for Asian medicines and "tiger bone" wine, Dollar and other conservation scientists say.

Top predators in Asia's jungles and Africa's savannahs, big cats do more than serve as national symbols. "Lions play a role in keeping migrations going, and keep populations in check," says naturalist Dereck Joubert, co-founder of the Big Cats Initiative. "Big predators play a role in keeping prey species vital and alert."

Biologists have documented that removal of top predators from wild settings almost inevitably leads prey numbers to explode, says John Robinson of the Wildlife Conservation Society, based at the Bronx Zoo. "Ecologically, focusing on protecting top predators just makes sense," Robinson says. "Protect them, and you are protecting the habitat for everything else."

Without top predators, booming prey populations soon strip vegetation and later collapse from illnesses and starvation. At Yellowstone National Park, elk devoured stream-protecting cottonwoods without wolves. Dolphins and sea cows wiped out sea grasses in Australia's Shark Bay without tiger sharks to chase them into deeper waters. Sea urchins ate kelp forests off Alaska's coast after sea otters numbers dropped in the late 1990s.

"The habitat doesn't recover," says photographer Beverly Joubert, Dereck's wife and BCI co-founder. "We're left with just hyaenas or their equivalent."

In Africa, as more herders develop lands that are home to big cats, the animals are killed by poaching, poisoning and livestock shrinking their ranges. In Central and South America, farmers have developed 39% of the original range of the jaguar, according to the September Smithsonian magazine. "We are seeing the effects of 7 billion people on the planet," Dereck Joubert says. "At present rates, we will lose the big cats in 10 to 15 years."

Over the past half-century, International Union for Conservation of Nature estimates show:

• Lions are down to perhaps 25,000 in the African wild, where 450,000 formerly roamed.

• Leopards are down to 50,000, from 750,000.

• Cheetahs number about 12,000, down from 45,000.

• Tigers number about 3,000 in the wild, down from 50,000 total. Perhaps only 1,200 breeding wild females exist.