Some 60 million years ago, well after the demise of the dinosaurs, a giant relative of today's boa constrictors, weighing more than a ton and measuring 13 meters long, hunted crocodiles in rain-washed tropical forests in northern South America, according to a new fossil discovery.

The fossil find - a batch of super-size vertebrae pulled from an open-pit coal mine in northeastern Colombia - is remarkable enough just as a paleontological extreme. The species, given the name Titanoboa cerrejonensis, is the largest known snake species ever discovered.

But the existence of such a large snake may also help clarify how hot the tropics became during an era when the planet, as a whole, was far warmer than it is now, and also how well moist tropical ecosystems can tolerate a much warmer global climate.