Sunday, March 4, 2012
I’m Faith Lapidus. And I’m Steve Ember with EXPLORATIONS in VOA Special English.
Today, we tell about the Galapagos Islands in the Pacific Ocean and the unusual creatures that live there.
Love is not easy to find when you are the last male of your kind. At least that is how it seems for the Galapagos Islands tortoise that scientists call Lonesome George. He is just one of the many animals and plants that live on the famous group of Pacific Ocean islands.
The islands were named for the large land turtles that live on them. At one time, the islands were home to about 15 different kinds of land turtles. The largest island, Isabela, has five different kinds of tortoises. But, Lonesome George is not one of them. He comes from a smaller island called Pinta.
Scientists found George in 1971. Humans and non-native animals had caused much damage to the environment on his island. Some animals and plants had disappeared. Lonesome George was the only tortoise found on Pinta.
Scientists took the turtle to the Charles Darwin Research Center on Santa Cruz Island. They wanted to help him find a female tortoise for mating to produce baby tortoises. The scientists had been successful in similar efforts for thousands of other tortoises
The researchers placed George in the same living area as females from the nearby island of Isabela. Scientists thought George would be more closely related to the females from Isabela than to other Galapagos tortoises. However, George has not been able to mate successfully with the female tortoises. No eggs have been produced. Scientists say this might be because of the genetic differences between George and the tortoises on Isabela Island.
Scientist Edward Lewis has studied the genetic material of tortoises around the world. But he has not found one with DNA like George’s. Scientists are also investigating George’s diet to make sure a lack of nutrients is not causing his failure to reproduce. He eats papaya fruit, grass and a special balanced diet. He weighs 88 kilograms.
Scientists also say there is a possibility that other tortoises might exist on George’s native island of Pinta. Scientists did not discover any other young tortoises when they removed George from the island more than 30 years ago. However, young tortoises are very small and like to hide.
Any other tortoises on the island would now be adults and might be easier to find. However, one major problem is that Pinta is thickly covered with plants. Scientists are planning to search the island for a possible mate for Lonesome George. If no babies are produced, the Pinta Island tortoises will disappear when George dies. He is between 70 and 80 years old. But some tortoises live longer than 150 years.
Mystery always has been part of the Galapagos. In 1535, a ship carrying the Roman Catholic Bishop of Panama came upon the Galapagos accidentally. Tomas de Berlanga named the Galapagos group the Enchanted Isles. He was surprised to see land turtles that weighed more than 200 kilograms and were more a meter long. He said they were so large each could carry a man on its back. Bishop Berlanga also noted the unusual soil of the islands. He suggested that one island was so stony it seemed like stones had rained from the sky.
The British nature scientist Charles Darwin is mainly responsible for the fame of the Galapagos Islands. He visited the islands in 1835. He collected plants and animals from several islands. After many years of research, he wrote the book "The Origin of Species." He developed the theory of evolution that life on Earth developed through the process of natural selection. The book changed the way people think about how living things developed and became different over time. Darwin said the Galapagos brought people near "to that great fact -- that mystery of mysteries -- the first appearance of new beings on earth".
More than 125 landmasses make up the Galapagos. Only 19 are large enough to be considered islands. The Galapagos are a province of Ecuador. The island group lies across the equator about 1,000 kilometers west of the coast of South America.
Scientists have been wondering for years about the position of the Galapagos in the Pacific Ocean. Scientists used to think that the islands were connected to the South American mainland and floated out to sea slowly
Today, most scientists think the islands were always where they are now. But they think the islands once were a single landmass under water. Volcanic activity broke the large island into pieces that came to the surface of the sea over time.
But scientists wonder how animals arrived on Galapagos if the islands were always so far from the mainland. Scientists think most Galapagos plants and animals floated to the islands. When rivers flood in South America, small pieces of land flow into the ocean. These rafts can hold trees and bushes. The rafts also can hold small mammals and reptiles. The adult Galapagos tortoise clearly is too big for a trip hundreds of kilometers across the ocean. But, turtle eggs or baby turtles would be small enough to float to the islands.
The islands are home to many unusual birds, reptiles and small mammals. Some of the animals live nowhere else on Earth. The tortoise is the most famous Galapagos reptile. But the marine iguana is also unusual. It is the only iguana in the world that goes into the ocean. The marine iguana eats seaweed. It can dive at least 15 meters below the ocean surface. And it can stay down there for more than 30 minutes.
Several strange birds also live on the Galapagos. One of them is the only penguin that lives on the equator. Another is the frigate bird. It has loose skin on its throat that it can blow up into a huge red balloon-like structure. It does this to attract females who make observation flights over large groups of males.
The Galapagos also are noted for a bird that likes water better than land or air. The cormorant is able to fly in all the other places it lives around the world. But the Galapagos cormorant has extremely short wings. They cannot support flight. But they work well for swimming.
The Galapagos Islands also have a large collection of small birds called Darwin’s finches. Charles Darwin studied the finches carefully when he visited the Galapagos in 1835. He separated the birds by the shapes of their beaks. Finches that lived in different places and ate different foods had different shaped beaks.
Scientists continue to study life on the Galapagos Islands. They have also studied the deepest parts of the ocean that surrounds the islands. A few years ago, the Smithsonian Institution in Washington, D.C. sent marine biologist Carole Baldwin to the Galapagos. Ms. Baldwin traveled 900 meters down to the bottom of the ocean near the islands. She did so in a clear plastic bubble watercraft called the Johnson Sea-Link Two.
The Sea-Link had powerful lights to battle the extreme darkness of the deep. The watercraft also had several long robotic arms. They collected sealife. The trips to the bottom of the sea resulted in the discovery of more than ten new kinds of sea life. Some of the discoveries were captured on film. A movie called "Galapagos: The Enchanted Voyage " was made in 1999.
The movie was filmed using the Imax Three-D technique. It was shown on a huge screen at the National Museum of Natural History in Washington for several years. Later, the movie was released on DVD for people to buy and watch in their own homes. The movie provides an experience similar to a 40-minute visit to the interesting and unusual Galapagos Islands.
This program was written by Caty Weaver. It was produced by Mario Ritter. I’m Steve Ember.
And I’m Faith Lapidus. Join us again next week for EXPLORATIONS in VOA Special English.