Size and Weight:
By far the biggest snake that ever lived--measuring up to 50 feet long and weighing north of a ton--Titanoboa presents a bit of a mystery. The fossils of this prehistoric snake--over two dozen more-or-less complete specimens of which were unearthed from a Colombian quarry in 2009--date from the Paleocene epoch, about five million years after the dinosaurs went extinct and millions of years before mammals evolved to giant sizes. In the absence of any comparably sized prey, one has to wonder what kind of evolutionary pressures caused Titanoboa to grow to its humongous size. (Of course, it's possible that Titanoboa was extant in late Cretaceous South America, and thus had the opportunity to prey on plus-sized titanosaurs, but there's no evidence in support of this. It's also possible that Titanoboa preyed on equally large prehistoric crocodiles, which would certainly make for a nifty TV special!) See 10 Facts About Titanoboa
One of the most interesting things about Titanoboa--besides its enormous size, of course--is what it reveals about its Paleocene habitat. Since all snakes are ectothermic (cold-blooded), they rely on the ambient temperature of their environment to heat up and cool down--and the sheer bulk of Titanoboa implies that Colombia was a much hotter place 60 million years ago than it is today. Paleontologists have extrapolated average temperatures in the range of 90 degrees Fahrenheit, which points to a previously unsuspected period of runaway greenhouse warming in this part of South America.
Recently, paleontologists discovered the fossil of a giant prehistoric turtle, Carbonemys, that lived at the same time and place as Titanoboa. While it seems unlikely, it's not out of the question that a full-grown Titanoboa and a one-ton Carbonemys occasionally met in battle, especially if one or both of them was very hungry. See Carbonemys vs. Titanoboa - Who Wins? for a blow-by-blow description of this epic encounter!