The largest snakes in world history, called Titanoboas, were recently discovered in Colombia. In fact, 28 fossils of the super snakes were found. They are believed to have been 42-49 feet long and weighed 2,500 pounds (previous records were 33 feet and 403 pounds.) Carlos Jaramillo, a staff scientist at the Smithsonian Tropical Research Institute, co-organized the team that discovered the biggest snake; the team included other Smithsonian scientists as well as experts from the University of Florida and other institutions. Smithsonian's Bruce Hathaway interviewed Jaramillo via e-mail about the find.
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Some of the giant crocodiles and turtles that the Titanoboas preyed on weighed 300 pounds. It's hard to imagine even these huge snakes capturing and killing such big crocodiles. How did they do it?
Maybe they hunted the same way was the largest snakes today, anacondas. Grabbing their prey near the shore, taking it to the water where they have the advantage, quickly wrapping themselves around its body and constricting it to death. It is not so unusual for a snake this big to prey on crocodiles, caimans and turtles; current-day anacondas do so in the plains of the Orinoco in Colombia and Venezuela.
Did these snakes have any natural enemies? How long did they live?
We think that their natural enemies attacked eggs and juveniles. The same crocodiles that Titanoboas themselves ate could have preyed on the big snakes' eggs and the young Titanoboas. We still don't know anything about their lifespans; that is very difficult to know from the fossil record that we have.
You say that your findings provide insights into the biological size limits on the evolution of snakes. What are some of the factors involved?
The upper growing limits of any organism are conditioned by the resources available, the physiology of each animal and physical forces such as gravity. Ambient temperature is especially important to cold-blooded animals; that's why the largest snakes on earth live near the Equator. Sixty million years ago, the Cerrejon region in the northeastern part of Colombia, where we found the Titanoboa fossils, was about ten degrees Fahrenheit warmer than today; it was a tropical jungle, actually the oldest known rainforest in the Americas. Snakes are cold-blooded, so the higher ambient temperatures allowed Titanoboas, which lived 60 million years ago, to grow larger than current-day snakes.
Can you please tell us more about the big snake fossil excavation process? How did you decide where to dig? About how long did it take to find the fossils?
We had been working in the mine for seven years. Cerrejon is the biggest open pit coal mine in the world, so the mine is opening new sites to explore on a regular basis. It took about two years to figure out that [the fossils were] a snake and collect enough material to be sure about it. Jason Bourque, a student at the University of Florida, was the first one that realized it was a snake; we had thought it was a crocodile because of its size.
One would think that open-pit coal mining would destroy fossils. Apparently not. Why not?
The fossils are usually below the coal seams so actually the mining uncovers the fossils for us; the mine is an ideal place to look for fossils. The big mining machines remove tons of coal and expose hundreds of square meters of rocks. That's where the fossils are.
Have you only found fossils of backbones? Do you think fossils of Titanoboa heads and mouths and teeth will ever be found? Will there ever be museum skeletal displays of these snakes similar to ones we have for dinosaurs?
So far we have only found vertebras and ribs, but we hope that we eventually find a skull and--why not?--a complete skeleton. We also hope that in the future, the remains of a Titanoboa as well as other fossils from Cerrejon will be displayed in many places. But first, we need to find more specimens, examine them and properly curate them.
How did you get involved in paleontology?
I was born in Colombia, and lived in Bogota until I was in my early '20s. I studied geology at the Universidad Nacional de Colombia in Bogota, and then did a Masters at the Missouri University of Science and Technology, and a PhD at the University of Florida. Then I worked for several years with the petroleum industry, and joined the Smithsonian 3.5 years ago. I live in Panama City now, in an area called Clayton, very close to the Panama Canal, surrounded by tropical rainforest. In the mornings I often see toucans, sloths, monkeys, snakes, and even crocodiles. I do not like cold weather. What I like most about my work is being in the field and using fossils to think about the past to understand our present and predict our future. Like Winston Churchill once said: "The farther backward you can look, the farther forward you are likely to see."
Working with fossils gives you a sense of humility, and you appreciate how lucky we are to be on planet Earth.
Can you tell us a little about what other projects you, Carlos, are now working on?
We are working on the early radiation of flowering plants in the tropics, studying sites in Brazil, Peru, Colombia and Cameroon. Also working on a vast lake that covered the entire Amazon 15 million years ago also working on the new excavations of the Panama Canal to unravel the history of the greatest of all biotic interchanges in earth history: the Panama Bridge, when South America and Central/North America got together 3.5 million years ago and finally, we want to understand why there is latitudinal diversity gradient (lots of species in the tropics, few in temperate regions)