How did 75 whales end up in the desert? Rows of prehistoric bones unearthed in one of the most significant discoveries of its kind

Last updated at 8:05 PM on 20th November 2011

Some believe they became disoriented and beached themselves, while others claim they were moved by a landslide and became trapped in a lagoon.

But scientists remain baffled as to how exactly scores of whales ended up in a desert more than half a mile from the sea.

The skeletons of 75 whales, believed to be more than two millions years old, were unearthed next to one another, just yards apart, in one of the world's best-preserved graveyards of prehistoric whales.

'Extraordinary': Prehistoric bones belonging to 75 whales have been found in the Atacama desert near Copiapo, Chile. Scientists remain baffled as to how they got there

Chilean scientists and researchers from the Smithsonian Institution are studying how the whales, many of them the size of buses, were found in exactly the same corner of the Atacama Desert in Chile.

The bones were unearthed near Caldera in June 2010 during a highway-widening project. So far, the fossils have been found in a roadside strip the length of two football fields.

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Experts say other groups of prehistoric whales have been found together in Peru and Egypt, but the Chilean fossils stand out for their staggering number and beautifully preserved bones.

Of the 75 whales discovered so far, more than 20 are perfectly intact skeletons. Researchers believe there could be hundreds more waiting to be uncovered.

Beached: The skeletons, which include a sperm whale and a now-extinct dolphin with tusks, were found more than half a mile from the South Pacific Ocean, seen above

Digging: The bones were found during a highway-widening project in 2010. Locals had seen bones poking through the ground but were unaware there were so many

They provide a snapshot of sea life at the time, and even include what might have been a family group: two adult whales with a juvenile between them.

‘I think they died more or less at the same time,’ Nicholas Pyenson, curator of fossil marine mammals at the Smithsonian's National Museum of Natural History, told the Associated Press.

‘There are many ways that whales could die, and we're still testing all those different hypotheses.’

Pyenson said the spot was once a ‘lagoon-like environment’ and that the whales probably died between two million and seven million years ago.

Experts said it will be hard to distinguish dates precisely enough to determine whether the whales all died simultaneously.

Most of the fossils are baleen whales that measured about 8 meters (25 feet) long, Pyenson said.

Preparation: A paleontologist encases a whale fossil to be taken to Chile's Paleontological Museum of Caldera. Most of the fossils are baleen whales measuring 25ft long

Discovery: The researchers believe the fossilized remains could have accumulated over a long period of time, between two million and seven million years ago

The researchers also discovered a sperm whale skeleton and remains of a now-extinct dolphin that had two walrus-like tusks and previously had only turned up in Peru, he said.

Findings: A video still shows Minister of National Assets Catalina Parot, using crutches, looking at one of the prehistoric whale fossils in the desert

‘We're very excited about that,’ Pyenson added. ‘It is a very bizarre animal.’

Other unusual creatures found in the fossil-rich Atacama Desert include an extinct aquatic sloth and a seabird with a five metre wingspan.

Erich Fitzgerald, a vertebrate paleontologist at Museum Victoria in Melbourne, Australia, said the latest find is very significant.

‘The fossils are exceptionally well preserved and quite complete — a rare combination in paleontology and one that will likely shed light on many facets of the ... ecology and evolution of these extinct species,’ Fitzgerald told AP.

He said it's possible ‘these fossilized remains may have accumulated over a relatively long period of time’.

Hans Thewissen, an expert on early whales, said another scenario is that the whales might have gathered in a lagoon and then an earthquake or storm could have closed off the outlet to the ocean.

‘Subsequently the lagoon dries up and the whales die,’ said Thewissen, a professor of anatomy at Northeast Ohio Medical University.

He called the accumulation of so many complete skeletons ‘a very unusual situation'.

'If this were a lagoon that dried up, you might see signs that ocean water evaporated," such as crystallized salt and gypsum in the rock, he said.

'On the other hand, if a giant wave or storm flung the whales onto shore, it would also have pushed the ocean floor around, and you would see scour marks in the rocks.'

The researchers have been told to finish their onsite studies so that fossils can be moved out of the path of the widened Pan American Highway, or Route 5, which is Chile's main north-south road.

'Significant': Researchers believe there could be hundreds more skeletons on the hill. They have been asked to moved the fossils so road work can continue

Location: The bones were found near Copiapo, around 440 miles north of Chile's capital, Santiago

Many of the fossils have been transported in plaster coverings to the museum in Caldera. Researchers from Chile's National Museum of Natural History are also studying the fossils.

With funding from the National Geographic Society, the Smithsonian team is using sophisticated photography and laser scanners to capture 3D images of the whales that can later be used to make life-sized models of them.

Suarez said the bones could always be seen jutting out of the sandstone ridge alongside the highway at the spot known as Cerro Ballena, or Whale Hill.

When the road work began last year, the construction company asked him to monitor the job to avoid destroying fossils.

‘In the first week, about six or seven whales appeared,’ Suarez said. ‘We realized that it was a truly extraordinary site.’

The Chilean government has now declared the site a protected zone.

Pyenson said he hopes a museum will be built to showcase the intact skeletons where they lie, in the same way fossils are displayed at Dinosaur National Monument in Utah and Colorado.

Suarez thinks there are probably fossils of hundreds of whales waiting to be uncovered — enough to keep him working at this one spot for the rest of his life.

'We have a unique opportunity to develop a great scientific project and make a great contribution to science,' he said