By Vicki Seal
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.
I went to see Lonesome George with Francisco, custodian of the tortoises at the research station. While George ate, there was a rustle in the bushes and another tortoise emerged, smaller than George but looking very much like him.
"Who is it?" I asked in my limited Spanish. "Another of Pinta?"
I couldn’t understand Francisco’s reply but it was clearly negative. Later when I talked to Gayle Davis of the research station she explained it to me.
"She’s from Volcan Wolf, the closest we can get to a Pinta form. She was put there to keep George active, because a tortoise’s sexual organs atrophy if they aren’t used. In fact" Gayle confided, "it’s already too late for our George."
Poor Lonesome George! Deprived of all company early in life, he was now condemned to a loveless old age!
I went again, of course, many times. Sometimes I took my camera with me and sometimes I didn’t. That was how I came to be leaning on the gate of George’s corral to witness the first signs of passion, with no means of recording it.
The female from Volcan Wolf was having a mud bath when George lumbered into action. "This is it," I thought, wondering whether to run for an expert or my camera.
He moved purposefully behind her and nudged her shell with the front of his own. I realised at this juncture that I was not about to run anywhere.
Startled, she climbed quickly out of the wallow.
"Go for it, George," I whispered.
He plunged into the mud-hole….and stayed there.
He gazed about with wise, unblinking eyes. When you’re an elderly tortoise and …well…past it, there’s nothing quite like a good mud bath.