It was the all-time titan of snakes -- a monster as long as a Tyrannosaurus rex that stalked a steamy South American rain forest after the demise of the dinosaurs and ate crocodiles for breakfast, lunch and dinner.
An international team of scientists on Wednesday announced the discovery in northern Colombia of fossil remains of the largest snake ever known to have lived. It is named Titanoboa cerrejonensis, meaning titanic boa from Cerrejon, the open-pit coal mine where its fossils were found.
Titanoboa was at least 43 feet (13 metres) long, weighed 2,500 pounds (1,140 kg) and its massive body was at least 3 feet (1 metre) wide, they wrote in the journal Nature.
It lived 58 million to 60 million years ago, when Earth's animal kingdom was still recovering from the mass extinction that doomed the dinosaurs and many other creatures 65 million years ago when an asteroid hit near the Yucatan coast of Mexico. It may have been the largest non-ocean vertebrate then on Earth.
"It is a mind-bogglingly big snake," paleontologist Jason Head of the University of Toronto Mississauga, one of the scientists, said in a telephone interview.
Paleontologist Jonathan Bloch of the University of Florida's Florida Museum of Natural History said, "When people think of Tyrannosaurus rex and how huge that thing was, this really is in the order of magnitude of Tyrannosaurus rex, in terms of length and in terms of caliber of gigantic."
Titanoboa was the largest inhabitant of a hot, lush tropical rain forest and probably hunted forms of crocodiles, large fish and big fresh water turtles. It was not venomous and likely lived a lifestyle akin to the large river-dwelling anacondas of today, wrapping around its unfortunate prey.
"This thing is a crocodile eater, catching and eating them in the water," Head said. "It was a bad day for the crocs."
Its ecosystem was similar to today's Amazon rain forest but hotter. The researchers estimated a snake of its size would have needed an average annual temperature in equatorial South America of 86 to 93 degrees Fahrenheit (30 to 34 degrees Celsius) to survive.
Of modern snakes, Titanoboa is most closely related to boa constrictors, except that it was the length of a school bus.
The scientists recovered fossil vertebrae and ribs, but no skull or teeth, from 28 different individuals. They think the largest Titanoboa may have been 49 feet (15 metres) or longer.
Snakes first appeared about 99 million years ago.
Previously, the largest known snake was Gigantophis, which lived about 39 million years ago in Egypt and was at least 33 feet (10 metres) long. The longest of today's snakes is the reticulated python, measuring perhaps 30 feet (9 metres).