Oldest Turtle in the World: LONESOME GEORGE
The rarest animal in the world today is a giant tortoise which lives in the Galapagos Islands.
There is only one Pinta Island tortoise (Geochelone elephantopus abingdoni). It is a male known by his keepers as Lonesome George. And when he dies the Pinta tortoises will be extinct.
Once there were millions of giant tortoises. In the age of the dinosaurs they covered most of the Americas, Europe and Asia. Like other dinosaurs they began to die out when mammals evolved and they were neither clever enough nor fast enough to compete for food.
But three million years ago, the Galapagos Islands burst out of the Pacific Ocean. For centuries these volcanic wastelands were bare. Then seeds carried by birds took root, the birds themselves stayed, and animals arriving on rafts of vegetation carried by ocean currents no longer perished.
Among there animals were the giant tortoises. They landed on 10 of the islands and have become adapted to the conditions of each. On arid, sparsely vegetated islands such as Pinta and Espanola only those with flared up shells and longer necks could reach the high-growing plants. In wetter regions such as Santa Cruz Island and southern Isabela they retained their domed shells and grew much bigger.
Charles Darwin, visiting the islands in 1835, saw that the tortoises on each island were different although they had obviously descended from a common stock which was now extinct on the mainland. This observation formed part of his world-changing Theory of Evolution by Natural Selection.
Before Darwin’s arrival the giant tortoises were in trouble again. Whalers, merchantmen and naval vessels took thousands on board as an insurance against scurvy, because the tortoises could live for up to 18 months without food or water. Settlers introduced farm animals. Pigs gone wild scoffed tortoise eggs, dogs killed juveniles, escaped goats and donkeys devoured the vegetation.
The Charles Darwin Research Station was opened on Santa Cruz Island in 1962 with the objective of protecting the remaining animals. By that time, five tortoises races had been declared extinct, among them the Pinta Island form.
Of those that were not extinct, several populations were precariously small. There were only 14 of the Espanola form, Geochelone elephantopus hoodensis. From lichen growths on the backs of the females it was clear that they had not mated for several seasons, probably because they had had to scatter so far in search of food.
Since 1965 the two males and twelve females from this island have been taken to the research station as breeding stock. It was further established that there was another male in San Diego Zoo, and he was transferred to the Galapagos colony. Meanwhile the National Parks Service began killing goats. Within 10 years almost all the goats were gone and vegetation on Espanola had been re-established.
The remaining Espanola tortoises are striking animals. With the exaggerated curves of their carapaces, their telescopic necks and small heads, they cannot be confused with tortoises from any other island. When startled they move with surprising speed, necks outstretched, long legs moving purposefully, and belying the legendary slothfulness of their kind.
The breeding venture has been very successful. Confined to a limited area and under the watchful eyes of scientists, these few mate and lay eggs as they once did on Espanola. For the first few years there were problems finding suitable nesting soil, but the staff of the research station persisted by creating artificial sites in the corral.
All eggs laid are transferred to incubating boxes so they will not be damaged by another female choosing the same site. Eggs must be handled carefully and kept in the same position as they were laid because the tiny embryo is soon attached to the eggshell, where it begins to grow.
The baby tortoises are kept at the research station until they are five years old, when they are taken to Espanola Island and released. At this age they are big enough to fend for themselves, and more are released every year while the 15 adults remain at the research station.
On Pinzon Island, mating and nesting of Geochelone elephantopus ephippium still takes place, but introduced black rats have overrun the island and they eat eggs and young. Until the research station stepped in, the population was steadily ageing. Now eggs are transferred to the research station and the young are released on Pinzon when they are big enough to resist attack. Rat traps and poisons are unthinkable in Galapagos so this work will be carried on indefinitely.
In December 1971 a scientist studying snails saw a solitary tortoise on Pinta Island. This was reported to the Galapagos authorities and a search was mounted. In 1972 National Park wardens killing goats on the island found the lone male and took him back to the research station.
The story of Lonesome George has travelled all around the world. Zoos have been offered a reward of $10,000 for a Pinta female. The reward has never been claimed.
Famous Galápagos Tortoise, Lonesome George, May Not Be Alone!!
ScienceDaily (May 1, 2007) — “Lonesome George,” a giant Galapagos tortoise and conservation icon long thought to be the sole survivor of his species, may not be alone for much longer, according to a multinational team of researchers headed by investigators at Yale University.
New research led by biologists Adalgisa Caccone and Jeffrey Powell in the Department of Ecology and Evolutionary Biology at Yale, with the strong support and cooperation of the Galápagos National Park and Charles Darwin Research Station, has identified a tortoise that is clearly a first generation hybrid between the native tortoises from the islands of Isabela and Pinta. That means, this new tortoise has half his genes in common with Lonesome George.
According to the Guinness Book of World Records Lonesome George, a native of Pinta, an isolated northern island of the Galápagos, is the “rarest living creature.” By the late 1960s, it was noted that the tortoise population on this island that is visited only occasionally by scientists and fishermen, had dwindled close to extinction, and in 1972, only this single male of the species Geochelone abingdoni was found.
Lonesome George was immediately brought into captivity at the Charles Darwin Research Station on the island of Santa Cruz where he is housed with two female tortoises from a species found on the neighboring island of Isabela.
“Even after 35 years, Lonesome George seems uninterested in passing on his unique genes and has failed to produce offspring,” said lead author Michael Russello of the University of British Columbia Okanagan who began working with the tortoises as a postdoctoral fellow at Yale. “The continuing saga surrounding the search for a mate has positioned Lonesome George as a potent conservation icon, not just for Galápagos, but worldwide.” Although Lonesome George has yet to find a tortoise partner, upwards of 50,000 people visit him each year.
The study, published in Current Biology, gives a peek into the evolutionary history of a species of Galápagos tortoise (G. becki) — previously known to be genetically mixed –on the neighboring island of Isabela. The results were possible only with advances in technology from these researchers that make DNA from ancient or museum specimens useful for genetic analysis.
Population analyses of a large database including individuals from all 11 existing species of Galápagos tortoises was compared to the genetic variation within two of the G. becki populations. DNA data for the nearly extinct G. abingdoni species from Pinta was available for the first time from six museum specimens — and from Lonesome George.
There are well over 2,000 tortoises of G. becki living on the neighboring volcanic Isabela Island, which has only two sites accessible from the sea. The research team collected samples from a total of 89 tortoises — 29 at one location, 62 on the other side of the island. Because the subset of the population they sampled was so small, the researchers hope that thorough sampling will locate a genetically pure Pinta tortoise.
The authors speculate that, in the event additional individuals of pure Pinta ancestry are discovered, a captive breeding and repatriation program could be set up for species recovery. “It will take a team of about 20 people about three to four weeks to do a first, exhaustive sampling and transmitter-tagging of the tortoises on the volcano,” said Caccone. “Then once individuals of interest are found — either hybrids with Pinta or pure Pinta animals — an equivalent field expedition will have to be mounted to find the animals and bring them in captivity. But, it is a harsh environment with no local resources and funding such an operation will be costly.”
According to Powell, “These findings offer the potential for transforming the legacy of Lonesome George from an enduring symbol of rarity to a conservation success story.”
Other authors on the paper are Nathan Havill from Yale, Luciano B. Beheregaray from Macquarie University in Sydney, Australia, James P. Gibbs from the State University of New York at Syracuse and Thomas Fritts from the University of New Mexico. The research was supported by the Bay Foundation, the Yale Institute for Biospheric Studies and the National Geographic Society.
Citation: Current Biology (May 1, 2007 — early online)
For more information on Lonesome George:
(Geochelone nigra abingdoni)
Just to give you an idea an idea just how big Lonesome George is:
That’s another (real) Turtle placed on top of his head