Mystery of Dead Whales

Image Credit: Flickr User Further to Fly, via CC

Discovery that led to the mystery

In 2010, the Pan American highway in Cerro Ballena, Chile was being expanded. Cerro Ballena lies in the Atacama desert, in Chile, in South America. Did you know that Atacama desert is the driest desert in the world? Cerro Ballena in Chile’s Atacama Desert is famous for preserved whale fossils. Whale bones often stick out of rock faces. Therefore, Cerro Ballena is also known as “whale hill”.

One day as the road work was in progress, construction workers saw something peculiar while digging. They saw skeletons. Many many skeletons. Many many gigantic skeletons. These skeletons turned out to be of marine animals that died 5 million years ago. 5 million year old fossils? What a chance discovery!

What happened next?

Immediately, a team of researchers led by US and Chilean Paleontologists was formed. Paleontologists are scientists who study fossils. For these scientists, it was a race against time. The road was next to a busy highway and was all dug up. Imagine fossils been discovered next to highway! Time was of the essence. The quarry had to be paved.

Scientists or Detectives

It is interesting to see how scientists worked towards solving the mystery. First of all, researchers documented the entire area along with the findings with the help of 3d digital tools. Then they carefully dug out the remains, cleaned and labelled them until all were collected. By the end, they had 40 skeletons including those of baleen whales, sperm whales, bony fish, extinct marine mammals, marlins and seals.

Now the big question before the scientists was – what or who killed so many gigantic marine animals?  The answer was complicated. Remember we are talking about something that happened millions of years ago. Scientists guessed that the mass death could be due to many reasons. Change in oceanography, environment, predators, or poisonous algae. Yes, Algae! Sometimes the algae that develops in the sea bed can be extremely poisonous and can effect the marine life fatally.

Putting together the Clues

Researchers examined and re-examined all the complex skeletons they had dug up. It was like putting puzzle pieces together.

They noticed that most of the skeletons showed that the animal died in the ‘belly up’ position. Now all whales have a throat pouch. When they die and decompose the throat pouch fills with gas making whales float on water like balloons. One thing was clear. Whales died in the sea, then floated ashore.

The site had fossils of various other marine animals other than whales. This gave them their next clue that the culprit could not have been any virus that kills only whales.

Their most important clue was the layers of fossils found on the fossils. This means that the animals were ingesting a lot of algae.


The killer was something belonging to the sea, not a predator and not a virus. Animals were not killed because of the changes in the environment.

With more than the usual algae found in the remains, scientists came to the conclusion that the killer was the deadly algae!!

Isn’t it exciting when scientists probe explore events from millions of years in the past or they run experiments to be able to predict what will happen millions of years from now? Would you like to be a scientist someday? Think about it!



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