PARIS: Stunned scientists have found the fossilised remains of the world's greatest snake – a record-busting serpent that was as long as a bus and snacked on crocodiles.
The boa-like behemoth ruled the tropical rainforests of what is now Colombia some 60 million years ago, at a time when the world was far hotter than now, they report in the U.K. journal Nature today.
The size of the snake's vertebrae suggest the beast weighed around a tonne, and measured 13 metres from nose to tail.
"Truly enormous snakes really spark people's imagination, but reality has exceeded the fantasies of Hollywood," said Jonathan Block, a vertebrate palaeontologist at the University of Florida, who co-led the work.
"At its greatest width, the snake would have come up to about your hips," said David Polly, a geologist at the University of Indiana at Bloomington.
The investigators found the remains of the new species at an unlikely location – at one of the world's biggest open-cast coalmines, in Cerrejon, Colombia, where giant machines had obligingly gnawed away surface layers of dirt.
Working as huge coal-laden trucks thundered by, the team sifted through the earth, laying bare the remains of supersized snakes and their likely prey – extinct species of crocodiles and giant turtles – and evidence that a massive rainforest once covered the ground.
Limited by temperature
"The giant Colombian snake is a truly exciting discovery. For years, herpetologists have argued about just how big snakes can get, with debatable estimates of the max somewhere less than [12 metres]," said leading snake expert Harry Greene of Cornell University, New York.
Titanoboa cerrejonensis – whose Latin name honours the coal mine – is not only a source of jaw-dropping wonder. It is also a useful indicator of the world's climate after the dinosaurs were wiped out some 65 million years ago, the team say.
Unlike mammals, reptiles cannot regulate their own temperature. As a result, they are limited in body size by the ambient temperature of where they live. For example, reptiles today are bigger in the tropics than they are in cooler latitudes.
Based on T. cerrejonensis, the scientists calculate that the mean annual temperature in equatorial South America 60 million years ago would have been 30 to 34 ºC. That makes it around 3 to 4 ºC hotter than tropical rainforests today.
If so, this is a welcome piece of news about climate change. Simulations about global warming suggest that, on present trends, the world's surface temperatures could rise by between 1.8 to 4.0 ºC by 2100.
If the supersnakes are a guide, tropical rainforests could still exist at such temperatures, although a fast, massive rise in warming could well be devastating to many species.
The world's longest snake today is the Asian reticulated python, specimens of which can grow around 10 m, and the biggest in terms of mass is the green anaconda, with some specimens weighing 227 kg