The Atacama Desert, in Chile, is a mass graveyard for nine million year-old whales. What gives?

Here’s a new paper, summarized in layman’s terms here, that explains the “whale graveyard” paleontologists had found in Chile. Turns out, the whales were toppled by nothing more than simple algae. At the time of first discovery of all this, in 2010, it was confusing scientists because there didn’t seem to be any natural predators (from a food chain perspective, orcas basically own the globe), and so the eventual results of this research were intended to give a better idea of the marine food chain in prehistoric times. Here’s how it started to piece together:

The most important clue came from the orientation of the bones. Many of the whale skeletons were found belly-up, suggested that they died in the sea. Also, the bodies were washed ashore quickly, before ocean scavengers could feed on them.

Some call the Atacama Desert finding “the most extraordinary marine mammal fossil site in the world.” Essentially, what seems to have happened is that the iron-rich Andes Mountains washed off into the coastal algae blooms. The iron-soaked algae poisoned the whales, who were then washed into a tidal flat. There were no large on-land predators in South America at the time, so the carcasses were preserved for millions of years. Kind of cool overall. The excellent preservation gave scientists a rare glimpse into how marine life worked nine million years ago; it’s the second South American location in the past five months or so that has been deemed extremely important to a global contextual picture of history.