The mystery of the pink dolphin: investigating an amazing animal
Detectives went on the trail of pink dolphin of the Amazon, the boto, a strange and rare animal. Their investigation took them around the world to put the pieces of a planetary and old puzzle over millions of years, complicated by continental drift. The story ends course along the Amazon River and looks like a movie. Besides, it is one ... but everything is true in The Mystery of the pink dolphin, a documentary by French Connection, in partnership with Futura-Sciences, and soon broadcast on France 5, July 11, in the program L empire science. Its author, Nicolas Bazeille, tells us.
What is he doing here at this dolphin called pink Inia geoffrensis, in the rivers of the Amazon basin, so far from the ocean where whales are born? There are other known or freshwater dolphins porpoises, Asia or America, of course, but their history is well known. How and why mammals adapted to marine life have they sneaked into fresh water, shallow and constantly fogged by sediment?
"We wanted to understand the origin of this animal," says Nicolas Bazeille, author of the documentary The Mystery of the pink dolphin, directed by Eric Ellena for French Connection Films, to whom we owe Peru, Extreme Planet. He tells this long investigation that began in Brussels by meeting paleontologist Olivier Lambert then goes on to Amsterdam, where we study the environments of the past, and North Carolina, where researchers are working on the remains of a whale older than ten million years.
This is an amazing global unfolding story and demonstrating how life evolves. "About ten million years before the present, several cetacean species have invested fresh water, reports Nicolas Bazeille. But they are not particularly related: each has adapted to his way. And the oldest of them is the pink dolphin of the Amazon, which seems appeared to -25,000,000 years. "
"The pink dolphin was born the Amazon ..."
Why did you do that? The answer comes from palaeobiologists and paleoecologists. Less impressive than the bones of dinosaurs, their working subjects are microscopic remains of pollen, animal shells or plant debris. With these tenuous clues, they can reconstruct an environment and explain for example that there are ten million years before the erection of the Andes, was a vast inland sea where today lie Venezuela and Colombia .
"The water was shallow, brackish and ribs were lined with mangroves. It was a very rich environment, where the cetaceans could easily find prey, and many species have adapted to this environment. "The birth of the Andes near the current Pacific Ocean coast has isolated this sea, which is closed. The pink dolphin was already there, installed, and survived the transformation of this vast region which has seen erected a chain of high mountains to the east by running huge amounts of fresh water. "The pink dolphin was born the Amazon ..."
The pink dolphin has through the ages
Do not adapt to this habitat that wants so different from the ocean. To live, you have to hunt in small spaces, surrounded by turbid waters where visibility is often almost zero. The pink dolphin has also a sophisticated echolocation system. Perhaps the competition with the other she has played cetacean species. "It is not very fast, swimming much less quickly than its cousins from the ocean, appeared later. His body is not very streamlined, it is even a little chubby, but it is flexible and agile, which is useful in a river. Perhaps the pink dolphin, in competition with other cetaceans, faster, more efficient, has he found a refuge. Finally, the morphology of the pink dolphin has changed very little over time, from the ocean into the river. I know that paleontologists do not like the term "living fossil", but it is well suited to this species. She crossed ages! "
The Amazon basin, teeming with lush life today it is still favorable and documentary shows us the boto home, observed by scientists and better protected in recent years. "The catfish fishermen used its meat as bait. And dams have divided its territory. But the safeguards seem to work. "
The story of pink dolphin continues
Under the leadership of Brazilian biologist Vera Da Silva, a regular population monitoring began in 1995, which demonstrated their decline, like all freshwater cetaceans. Measures have been taken, including the creation of the Mamirauá Reserve, which today houses the largest population of pink dolphins. The animals are captured for auscultated and the team was surprised to find a female who had experienced two pregnancies close together, which is not usual.
The history of the pink dolphin continues, probably. In 2014, as reported Futura-Sciences, Tomas Hrbek and his colleagues discovered that the pink dolphin of the Araguaia, Brazil, actually belonged to another species, called araguaian river dolphin. Genetic analysis showed that the two have diverged there just over two million years, which is no coincidence. "This is the time when the Tocantins river which flows in the Araguaia and came to the sea, has been diverted to become a tributary of the Amazon. Populations were separated "... and followed their separate different stories.
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