Arguably the most important marine mammal fossil collection ever found, Cerro Ballena, or “whale mountain” has left experts guessing for years at what could have killed the hundreds of perfectly preserved specimens buried deep in Chile’s arid north. Among the animals unearthed in this groundbreaking site were whole families of whales, strange aquatic sloths, giant and terrifying predatory fish and mysterious whales with heads similar to that of a walrus — all of huge value in experts’ quest to unravel the mysteries key of the evolution of marine mammals.
Scientists have been investigating what could lead to the apparently simultaneous death of hundreds of animals of different species between 9 and 6 million years ago since the remains where found in 2010. But now this ancient riddle has finally been solved by a dedicated team featuring Chilean and international experts alike.
The mystery began when construction workers, busy expanding the country’s Pan American Highway, stumbled upon an incredible array of fossils millions of years old.
From that moment the race was on. While the significance of the find was immediately apparent, the need to resume work on the transnational superhighway meant paleontologists had mere weeks to catalogue this vast find. Their solution was to employ state of the art technology to document the findings in perfect detail using 3D capture.
“It was a time sensitive solution — we didn’t have time to conduct the traditional methods — quarry maps, drawing out bones on a grid,” paleontologist Nick Pyenson said in an interview with The Santiago Times.
Pyenson was part of an international team of experts and worked closely with several prestigious Chilean institutions in an effort to use the latest technology to capture this unique discovery.
“While it was exciting it was also challenging because no one had done this — collecting the data in this way and processing it,” he said of the 3D scanning process. “We were doing it for the first time, we had a vision of how to do it but here were new challenges every day. The Natural History Museum in Santiago and the Universidad de Chile were very strong partners in achieving all of this.”
Finally after years of investigation, experts were able to rule out theories such as a giant tidal wave and concluded the real mass killer was something less dramatic but incredibly devastating for the local marine mammal populations: deadly toxins in local sea vegetation known as a Harmful Algal Blooms (HABs)..
“[HABs] explain the diversity of species we found and the unusual skew towards large marine animals that are high up in the food web — we don’t find any fish there, except for very large predatory fish. Those are all clues,” explained Pyenson. “The reason why HABs can kill large marine vertebrates is because the toxins become more concentrated along the food web.”
Making headlines across the world, this amazing find has generated huge interest and now Pyenson and the team behind the discovery hope a dedicated station may be built near the site.
“It’s ideal for a research station of some kind, and right now Universidad de Chile is taking a leadership role in that,” he said. “I hope that we can inspire enough interest in this place to merit having that kind of permanent structure to house and show the fossils there. All you have to do is turn off the Pan American Highway and dig into the hillside and I guarantee you’ll find whale skeletons.”
To explore the fossil finds for yourself, visit the Cerro Ballena website.