Darwin, a naturalist's voyage around the world

STAGE 7

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Le voyage de Darwin

STAGE 7

6 December 1833 - 10 June 1834
Patagonia, biodiversity, Tierra del Fuego, Rio Santa Cruz, Pacific


On December 6, the Beagle left Montevideo for good. One evening, off the east coast of South America, the ship was caught up in a huge cloud of butterflies, stretching as far as the eye could see. The sailors cried out that it was snowing butterflies! Darwin sought an explanation for their presence so far from land: had they been blown there by the wind? Or was it a vast migration? He was unable to decide.

On December 23, the ship dropped anchor at Port Desire (now Puerto Deseado) in Argentina. The fauna and flora suffered from the aridity of the area, drastically limiting their diversity. Only a few cacti, thorny shrubs, guanacos, beetles, lizards and birds appeared to populate this remote region. While out walking, Darwin discovered an ancient Indian tomb.

On January 9, the ship put in at the beautiful, wide harbor of Puerto San Julián, situated less than 200 kilometers south of Puerto Deseado. But the surrounding countryside appeared even more barren. Darwin, Captain FitzRoy and a few members of the crew set off to explore. They walked for eleven hours without finding the least drop of fresh water, of which they were to find none during their entire stay. Near the harbor, Darwin came face to face with a skeleton of Macrauchenia patachonica, an extinct pachyderm whose neck bones were reminiscent of the llama. He wondered what could have led to the extinction of all the species whose remains he had found since the beginning of his voyage. Was it extermination by humans, competition between species, natural extinction? There were several possible explanations.

At the end of February, the Beagle arrived off Tierra del Fuego, at the southernmost tip of the continent. The moment of truth had arrived for Captain FitzRoy: had the three natives whom he had provided with an education in England managed to run the mission station they had built the year before and 'civilize' their fellows? On March 5, the ship dropped anchor at Woollya. The mission station was empty: there had apparently been a battle. An almost completely naked Fuegian arrived in a small boat. It was Jemmy Button, one of the three anglicized natives. He had completely reverted to the native way of life, and appeared somewhat shamefaced in the presence of the crew. He informed them that the two other Tierra del Fuego natives educated by FitzRoy had fled after stealing his belongings. The Captain had lost his bet. The only consolation was that Jemmy had taught his tribe a few words of English. But he didn't wish to return to England, because he now had a pretty young wife. When they left, there were emotional farewells.

On March 16, the Beagle stopped off in the Berkeley Sound, on East Falkland. Cold weather, winds and blizzards greeted Darwin as he travelled into these wet regions populated by wild geese, loggerheaded ducks, jackass penguins, foxes, rabbits and a few birds. The naturalist was intrigued by two recently introduced species, cattle and horses. Whereas the former appeared to be perfectly adapted to their new environment, surprisingly the horses remained confined to one part of the island, and appeared to be degenerating. The attention of the young Darwin was also drawn towards myriads of large fragments of jagged rock that formed amazing 'rivers of rock', evidence of a past seismic event of huge energy. And yet, surprisingly, there was no trace of an earthquake of this nature in the historical records.

On April 13, the Beagle arrived at the mouth of the Rio Santa Cruz on the coast of Argentina. On the 18th, Darwin, FitzRoy and twenty crew members set off to explore the mysterious river on board three whaling boats. However, the current was so fast that the men had to land quickly and tow the boats along with the help of ropes. The explorers made slow, exhausting progress, under the watchful eyes of the condors gliding overhead. And to make matters worse, evidence of horses and spears indicated that Indians were on their trail. But despite everything, the young naturalist was fascinated by the study of the geological structures that surrounded them. His observations convinced him that the cliffs on either side of the river, as well as the Andes Cordillera itself, were the result of slow uplift above sea level. On May 4, supplies started to run out, and the Rio Santa Cruz started to become faster and increasingly tortuous. FitzRoy decided to turn back, putting an end to the aim of reaching the Andes, which were already making the air chilly. Although it had taken them seventeen days to go up river, it only took them three to get back down!

In the second half of May, the ship arrived at the eastern mouth of the Strait of Magellan, which connects the Atlantic to the Pacific at the south of the continent. The ship put in at Port Famine (now Puerto del Hambre) on June 1, as winter settled in. Dark, dank forests covered the slopes of the mountains, which were crowned with glaciers. On the morning of June 10, after a pitch-dark night lasting fourteen hours, the Beagle at last sailed through into the Pacific.

CNRS    sagascience