A Nightmare Snake Once Roamed the Colombian Swamps

Dinosaurs were not the only gigantic reptiles in prehistoric South America. There were also snakes as long as a school bus, immense crocodiles and alligators, and the largest turtles that ever lived.

People have a strange relationship with snakes. Most of us fear them, and some people are so acutely afraid of them—a condition called ophidiophobia—that they have panic attacks and break out in sweats when they even see an image of one. Many animals fear snakes as well, possibly since certain snakes are among the few creatures with venom strong enough to sicken or kill humans and large animals.

As they roamed the African savannah millions of years ago, our earliest hominid ancestors probably were hard-wired to fear and avoid snakes as a deadly threat, since cobras, mambas, vipers, and many other killers lurked in the grass. Sadly, most Americans fear snakes and kill the harmless ones unnecessarily, even though the vast majority of American snake species are not venomous.

Yet this fear of snakes is matched by fascination. Many different cultures have had snakes in their religion and mythology, some as benevolent deities and others as evil presences. The ancient Egyptians worshiped the cobra, and a sculpture of a cobra adorned the crown of the pharaoh. In Greek myths, the Gorgon Medusa had snakes on her head instead of hair, and a glance at her turned you to stone. Hercules had to kill the Lernean Hydra, a creature with nine snakelike heads, which grew a new head as soon as one of them was cut off. In Hindu, Chinese, Maya, and Hebrew traditions, among many others, snakes take a central role in important stories explaining the world and its ways.

Some cultures have imagined huge mythical snakes performing important roles in their religious traditions. But no one could imagine a monster snake three times the size of the largest living anacondas and pythons, let alone that such a creature once lived and roamed in South America.

The discovery of that creature, an accidental discovery at that, happened in a giant open-pit coal mine in northwestern Colombia, about 60 miles from the coast. The mining pits are some 15 miles across and cover an area larger than Washington, D.C. This mine is excavating thick coal seams from a geologic unit called the Cerrejón Formation, taking 31.5 million tons of coal from the ground each year, making it the largest coal mine in Latin America.

In 1994, local geologist Henry Garcia found what he thought was a petrified tree branch and put it in a display case in the coal company’s office. Nine years later, a college geology student, Fabiany Herrera, found beautifully preserved fossil leaves and showed them to state geologist Carlos Jaramillo. Jaramillo brought in Scott Wing of the Smithsonian, an expert on Paleocene plants, and soon they had huge collections of beautiful fossil leaves from the hot jungles of ancient Colombia. Wing took a picture of the supposed petrified branch and showed it to paleontologist Jonathan Bloch of the University of Florida Museum of Natural History in Gainesville. Bloch immediately recognized it as the jaw of a group of extinct crocodiles called dyrosaurs.

The staff at the University of Florida Museum began working on the Cerrejón locality at an abandoned pit called La Puente in 2004. As reported in Smithsonian,

La Puente is a forbidding, naked surface of soft mudstone cut by gullies leading downslope to a lake filled with runoff and groundwater. The only vegetation is an occasional scraggly bush clinging to the scree. The pit shimmers at temperatures above 90 degrees Fahrenheit, while a hot wind blows constantly, with 25-mile-per-hour gusts. Methane fires belch periodically from the naked cliff face across the lake. Immense trucks can be spotted in the distance, driving loads of coal scooped up after blasting. The mudstone was the paleontological pay dirt. “Wherever you walked, you could find bone,” Bloch said, recalling the wonder of the first trip. During that expedition, in 2004, the researchers grabbed everything they saw, and everything was big: ribs, vertebrae, parts of a pelvis, a shoulder blade, turtle shells more than five feet across. They found bits of dyrosaur and turtle everywhere, and other animals as well, but the team could not sort everything immediately. They put what they could in plastic bags, then dug pits and cast the big pieces in plaster of Paris. “It’s like prospecting,” Bloch said. Walk along with brushes and tweezers and eyes focused on the ground until you find something you want. Put the little bits in plastic bags and label them. Mark the bigger pieces on a GPS device and come back the next day with plaster and a tarp. Wait too long, and the GPS reading is useless: The rain is a curse, washing everything down the slope, never to be seen again. But the rain is also a blessing, for when it stops, a whole new fossil field lies open for exploration.

In 2007, University of Florida graduate student Alex Hastings was unwrapping packages of fossils that had been shipped from Colombia. Among the packages was a single vertebra from the backbone of a very large reptile. Based on its size, the collectors in the field had labeled the package as a “croc.” Hastings knew at once that it did not belong to one of the many crocodiles found in the locality. He showed it to fellow graduate student Jason Bourque, a reptile specialist. Bourque knew at once that it came from a snake, and a huge one. They quickly walked over to the museum’s reptile collections and found a box with the skeleton of an anaconda in it. Sure enough, when they compared the two specimens, the fossil was unquestionably from a large snake like an anaconda—but it was more than three times as large! The anaconda is the heaviest snake on the planet at 215 lbs, as well as one of the longest, reaching 22 feet.

Bourque and Hastings began going through all the miscellaneous fossil vertebrae in the Cerrejón collections that had not been clearly identified. Soon they had more than a hundred huge snake vertebrae representing at least twenty-eight different individual gigantic snakes. Then they showed their discovery to their supervisor, Jonathan Bloch. A specialist in fossil mammals, he too had collected many of the large vertebrae but not realized what they were. As he put it, “We’d had some of them for years. 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.”

As soon as Bloch realized what they had, he called Jason Head, then at the University of Toronto. Head is one of the few people in the world who could tell him what kind of snake it was and how big it was. The two of them had met back in the early 1990s when they were both students at the University of Michigan. Bloch assembled a tray of “a whole bunch” of bones, brought them to his Florida office, and called up Head on iChat, holding the bones up to the computer camera. Thanks to modern technology, Head could see in real time what used to require weeks to photograph, process, and mail back and forth. Within seconds of viewing a few of the specimens more than 2,000 miles away, Head told Bloch, “I’m buying my ticket tonight!

As soon as he arrived in Gainesville, Head began studying the specimens and confirmed that they came from a monster snake larger than any other that has ever lived. Snakes are very rarely fossilized, since their bones are delicate and easily broken, and their long string of vertebrae and ribs tend to fall apart when they die. In addition, there is a problem with estimating the size of snakes because you seldom find the complete skeleton intact. Most often, you find a few vertebrae and not much else, since the ribs are very slender and fragile. Snakes keep adding new vertebrae to their backbones as they grow, so a large anaconda can have as many as three hundred vertebrae in its spine. By contrast, you have only thirty-three vertebrae in your spine and never add any. Most other mammals have about that many, too, not counting the tail.

For years, most scientists had just collected snake vertebrae and stopped there, since no one had figured out a method to tell which part of the spine each individual vertebra was from. But Head and Dave Polly of Indiana University had been working hard on a technique for telling exactly where in the spine each bone might come from. Each bone is distinctive to a region in the snake’s back, although no one had taken the time to really notice this before. From this, Head and Polly were able to tell where most of the fossil vertebrae came from and get a more accurate estimate of the snake’s length.

The skull of a snake is constructed of many thin struts of bone held together by tendons and ligaments and muscles. This allows snakes to completely unhinge their jaws, stretch their mouths around prey much larger than their heads, and still swallow it whole. Unfortunately, it also means that the skull bones are very delicate as well, very loosely attached to one another, and easily scattered when the animal dies.

In 2011, the Cerrejón team found a skull of the gigantic snake. This confirmed what they had suspected: The monster snake was a constrictor, like the anaconda, the python, and the boas.

In 2009, Head and his collaborators had published their findings and formally named the creature Titanoboa, or “titanic boa constrictor.” Even though they did not have a complete spine, they had enough pieces to estimate its length at between 42 and 49 feet long. Scaling up its size from the known weight of anacondas and other large boas, they estimated that it weighed about 2,500 lbs, as much as a full-grown rhinoceros.

The Age of Mammals may have prevailed over most of the earth for the past 65 million years, but in South America it was still the Age of Reptiles, from the gigantic flying and running birds to the immense crocodilians and caimans, turtles, and monster anacondas. 

Read more in Giants of the Lost World, which is available from Smithsonian Books. Visit Smithsonian Books’ website to learn more about its publications and a full list of titles. 

Excerpt from Giants of the Lost World Text © 2016 by Donald R. Prothero