Most people have never heard of the Cerrejón coal mine, located in Colombia. The mine pumps out over 30 million tons of coal each year, and it's also become a critical site for scientists. In fact, the coal mine ranks as one of the best fossil sites in the world, providing a window into a tropical rain forest from 60 million years ago. Scientists almost missed the fossils at Cerrejón - until an undergraduate noticed a surprising number of sandstone impressions of fossil leaves. His discovery led to an expedition that found multiple new species, including the largest snake in history.
The nearly 50-foot prehistoric snake called Titanoboa hunted crocodiles and giant turtles in the swamp. It was as long as a school bus and weighed 2,500 pounds. And Titanoboa wasn't the only surprise hiding in the Colombian coal mine. Scientists found other enormous prehistoric animals, like a 16-foot crocodile they named after a character from The Lord of the Rings.
Cerrejón, the coal mine that contains a treasure trove of fossils, gave paleontologists a glimpse into a world long forgotten - and almost lost, if not for a curious student and some helpful miners.
In the early 2000s, geology major Fabiany Herrera visited Cerrejón as part of a field trip. Herrera was an undergraduate at the Industrial University of Santander in Colombia. He made a startling discovery by merely picking up a piece of rock at the coal mine. Herrera found impressions from prehistoric leaves on every single rock he examined.
Herrera took the rocks to Carlos Jaramillo, a scientist working for Colombia's oil company. The discovery excited Jaramillo so much that he called up the Smithsonian and invited a paleobiologist to visit the coal mine. Along with Herrera, the team undertook the first fossil hunt in Cerrejón in 2003.
The coal company that mined Cerrejón knew there were fossils in their pits. In 1990, a geologist named Henry Garcia picked a fossil up from the ground and put it on display back at the office. Garcia wasn't sure of the fossil's identity, so he called it "Petrified Branch."
In 2003, paleobiologist Scott Wing took a picture of the "Petrified Branch" and sent it to a paleontologist friend named Johnathan Bloch. “I flipped out,” Bloch recalled. He knew it wasn't a petrified branch at all, but the fossilized jawbone of an animal. It was the first fossil from a land vertebrate found in tropical South America.
Bloch immediately flew to Colombia to look at the fossil, but no one could find the key to the display case. Instead, the eager scientists broke the glass and confirmed the major find.
Scientists discovered fossils from the largest snake in history at Cerrejón. Named Titanoboa, the snake species grew up to 49 feet long and weighed more than two tons, and it dominated the tropical swamp. Scientists say the Titanoboa looked like a cross between a boa constrictor and an anaconda, but much larger.
Titanoboa hunted enormous turtles and crocodiles, making it an apex predator. And scientists didn't just find one snake at the Colombian coal mine. By 2009, the digs had uncovered nearly 30 snakes, all of which measured at least 42 feet long. According to paleontologist Carlos Jaramillo, "What we have is a population of big snakes. It's not one snake. It's a bunch of them."
Titanoboa was hiding in plain sight at the coal mine. When paleontologists began collecting fossils in 2003-2004, they were overwhelmed by the number of items. A large group was mislabeled as prehistoric crocodile vertebrae because of their size.
It wasn't until 2007 that scientists realized they belonged to a snake. Johnathan Bloch explains:
My only excuse for not recognizing them is that I’ve picked up snake vertebrae before. And I said, "These can’t be snake vertebrae." It’s like somebody handed me a mouse skull the size of a rhinoceros and told me "That’s a mouse." It’s just not possible.