RENEE MONTAGNE, host:
Imagine, for a moment, the world's largest snake. If a vision of a boa constrictor comes to mind, think bigger - much bigger. The biggest snake that ever lived reached 42 feet, about the length of a school bus. That's according to scientists who found the vertebrae of this super serpent in the rainforests of Colombia. NPR's Christopher Joyce has this report. [POST-BROADCAST CORRECTION: In fact, the area where the bones were found is no longer a rainforest, although it was when the snake was alive, millions of years ago.]
CHRISTOPHER JOYCE: It's tempting to wait 'til the end of the story to reveal that this snake is extinct, but that wouldn't be fair. So OK, Titanoboa cerrejonensis lived 60 million years ago, but one can still imagine, as big around as a trash barrel, weighing over a ton.
Jason Head is a paleontologist at the University of Toronto, who studies big snakes that once roamed through the earth - or slithered, that is. A colleague in Colombia, South America called and said he'd found some huge bones from a very long spinal column. They set up a video conference so Head could see them.
Dr. JASON HEAD (Paleontologist, University of Toronto): He held one specimen up to the camera and I just about jumped out of my chair. And we were both just sitting there laughing, because it was so ridiculously big. It was a vertebra the size of his hand. You know, it was - we were both just blown away. And I said I know this is the world's largest snake.
JOYCE: Titanoboa inherited the earth after the dinosaurs died out 65 million years ago.
Dr. HEAD: Between the end of the age of dinosaurs and about 45, give or take a couple of million years, this is the single largest terrestrial vertebrate.
JOYCE: On land the Titanoboa was boss. It ate, well, whatever it wanted. Most meals were primitive crocodiles, al dente. But Head says size isn't the whole story here.
Dr. HEAD: We realized right away that it was telling us a story, that the fact that there was a snake this big has to mean something about the environment.
JOYCE: Something about how hot the tropics were then and maybe how hot they could get again. Here's why. This snake was presumably cold-blooded. To survive with that big a body it had to live in a very hot place. To be exact, says Head, a rainforest averaging 32 degrees Celsius, more or less, or 90 degrees Fahrenheit. That's several degrees warmer than now and several degrees warmer than scientists thought the tropics could ever get, even during a greenhouse period.
Dr. MATTHEW HUBER (Climate scientist, Purdue University): There's an old idea that the tropical regions have a thermostat and they just can't get hotter than about 28, 29, 30 degrees C.
JOYCE: That's Matthew Huber, who studies ancient climates at Purdue University. Essentially, the idea has been that the tropics just don't warm up that much during global warming periods, even as the rest of the world does. Huber says the snake evidence suggests otherwise.
Dr. HUBER: And if that's the case, that's in some sense bad news for us for the future. It says there's no magical thermostat that keeps the tropics at a reasonable temperature that they will warm to in a global warming world.
JOYCE: If, he says, that is the case. No one has ever used a fossil snake before as a measure of ancient climate. Huber says the work will need some confirmation. But, he adds, there might also be a bright side here. Many biologists thought that tropical forests would simply die if they got significantly hotter.
Dr. HUBER: And this suggests that at least on long time scales the tropics are quite happy to be significantly warmer than they are today.
JOYCE: Though if the tropics do get warmer don't expect a reappearance of Titanoboa-sized snakes. They'll remain a scientific curiosity described in this week's issue of the journal Nature.
Christopher Joyce, NPR News.
MONTAGNE: The snake is really, really big. And I know, because I'm looking at a picture of it at npr.org. You can too by going to our Web site.
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