The discovery of Lonesome George in 1971 set off a frantic search on the Galapagos Islands for other Pinta tortoises. �We haven�t managed to find another one,� caretaker Fausto Llerena says. �Just skeletons.� The 100-year-old tortoise has yet to find a mate. Illustrates TORTOISE (category i), by Ernesto Londono (c) 2011, The Washington Post. Moved Tuesday, May 10, 2011.
And then there were none. Lonesome George, known as the sole surviving Pinta Island tortoise, died in the Galapagos, possibly of heart failure. He was 100 or thereabouts. He may have been Earth's rarest creature, but Lonesome George's fate has been a common one for megafauna ever since humans came along. The Americas were once a dreamscape of giant mammals, from bears the size of Ford Explorers to giant sloths larger than today's elephants. They all disappeared around 10,000 B.C., not long after the first people are believed to have made their way down from the Bering land bridge.
Some paleobiologists blame the die-off on climate change, since it also coincided with the end of the last Ice Age. But extinctions have continued at a rapid clip throughout the Holocene Epoch, in which humans have come to dominate. This has led to fears that we're in the midst of a Sixth Great Extinction. (The fifth involved dinosaurs.) Megafauna are a tiny fraction of the thousands of species that vanish each year, but that's because there weren't that many of them to begin with. Of those that remain, many are hanging on in tiny numbers.
Lonesome George, who outlived his last relatives by decades, was an extreme example. (His kin were apparently done in by feral goats, which demolished the vegetation after humans introduced them to the island.) But there are only a few hundred Siberian tigers, fewer than 1,000 mountain gorillas and a few thousand black rhinoceroses. (The Western black rhino was declared extinct last year.) And if there are any remaining Baiji -- also known as Chinese river dolphins -- they probably number in the single digits. When Galapagos National Park officials first spotted Lonesome George in 1971, they were overjoyed -- they had thought his group extinct. They tried for decades to entice him to mate with female tortoises from neighboring islands, but without success.