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| Largest snake 'as long as a bus' | Largest snake 'as long as a bus' |
| (about 5 hours later) | |
| The discovery of fossilised remains belonging to the world's largest snake has been reported in Nature journal. | The discovery of fossilised remains belonging to the world's largest snake has been reported in Nature journal. |
| Titanoboa was 13m (42ft) long - about the length of a bus - and lived in the rainforest of north-east Colombia 58-60 million years ago. | Titanoboa was 13m (42ft) long - about the length of a bus - and lived in the rainforest of north-east Colombia 58-60 million years ago. |
| The snake was so wide it would have reached up to a person's hips, say researchers, who have estimated that it weighed more than a tonne. | The snake was so wide it would have reached up to a person's hips, say researchers, who have estimated that it weighed more than a tonne. |
| Green anacondas - the world's heaviest snakes - reach a mere 250kg (550lbs). | Green anacondas - the world's heaviest snakes - reach a mere 250kg (550lbs). |
| Reticulated pythons - the world's longest snakes - can reach up to 10m (32ft). Snakes had the opportunity to evolve and grow as big as this one did in a way that they probably wouldn't today P David Polly, Indiana University | |
| The team of researchers led by Jason Head, from the University of Toronto at Mississauga, Canada, used a known mathematical relationship between the size of vertebrae and the length of the body in living snakes to estimate the size of the ancient animal. | The team of researchers led by Jason Head, from the University of Toronto at Mississauga, Canada, used a known mathematical relationship between the size of vertebrae and the length of the body in living snakes to estimate the size of the ancient animal. |
| Named Titanoboa cerrejonensis by its discoverers, the beast's 13m-long body and 1,140kg (2,500lb) weight make it the largest snake on record. | Named Titanoboa cerrejonensis by its discoverers, the beast's 13m-long body and 1,140kg (2,500lb) weight make it the largest snake on record. |
| "At its greatest width, the snake would have come up to about your hips. The size is pretty amazing," said co-author P David Polly, from Indiana University in Bloomington, US. | "At its greatest width, the snake would have come up to about your hips. The size is pretty amazing," said co-author P David Polly, from Indiana University in Bloomington, US. |
| Researchers discovered fossilised bones belonging to the super-sized slitherers and their possible prey at Cerrejon, one of the world's largest open-pit coal mines. The animal is a relative of modern boa constrictors. | Researchers discovered fossilised bones belonging to the super-sized slitherers and their possible prey at Cerrejon, one of the world's largest open-pit coal mines. The animal is a relative of modern boa constrictors. |
| Warming world | Warming world |
| "Probably like an anaconda, it spent a lot of time in the water," said Professor Polly. | "Probably like an anaconda, it spent a lot of time in the water," said Professor Polly. |
| Palaeontologist Dr Jonathan Bloch looks through fossils of the giant snake | |
| "It would have needed to eat a lot. | |
| "What its prey was exactly, we don't know. But it probably included alligators, big fish or crocodiles." | |
| The researchers also used the reptile's size to make an estimate of Earth's temperature 58 to 60 million years ago in tropical South America. | The researchers also used the reptile's size to make an estimate of Earth's temperature 58 to 60 million years ago in tropical South America. |
| Palaeontologists have long known that as temperatures go up and down over geological time, generally speaking, so does the upper size limit of cold-blooded creatures - or poikilotherms. | |
| This is because the metabolism of a poikilotherm is more or less controlled by the average temperature of its environment. | This is because the metabolism of a poikilotherm is more or less controlled by the average temperature of its environment. |
| Assuming the Earth today was not particularly unusual, the researchers calculated that a snake of Titanoboa's size would have required an average annual temperature of 30C to 34C (86F to 93F) to survive. | Assuming the Earth today was not particularly unusual, the researchers calculated that a snake of Titanoboa's size would have required an average annual temperature of 30C to 34C (86F to 93F) to survive. |
| By comparison, the average yearly temperature of today's Cartagena, a Colombian coastal city, is about 28C. | By comparison, the average yearly temperature of today's Cartagena, a Colombian coastal city, is about 28C. |
| Opportunity knocks | Opportunity knocks |
| "A snake living in the tropics would have been operating at a much higher metabolic rate," said Professor Polly. | "A snake living in the tropics would have been operating at a much higher metabolic rate," said Professor Polly. |
| "So snakes had the opportunity to evolve and grow as big as this one did in a way that they probably wouldn't today."Titanoboa (r)" border="0" vspace="0" hspace="0">A vertebra from an anaconda (l) is dwarfed by one from Titanoboa (r) | |
| He added that as the Earth warmed up in future, cold-blooded animals could be expected to evolve larger bodies. | He added that as the Earth warmed up in future, cold-blooded animals could be expected to evolve larger bodies. |
| Dr Head adds that the find "challenges our understanding of past climates and environments, as well as the biological limitations on the evolution of giant snakes." | Dr Head adds that the find "challenges our understanding of past climates and environments, as well as the biological limitations on the evolution of giant snakes." |
| However, Dr Matthew Huber, a climatologist from Purdue University in Indiana, who was not connected with the study, questioned whether the link between size and temperature was "generalisable and accurate". | However, Dr Matthew Huber, a climatologist from Purdue University in Indiana, who was not connected with the study, questioned whether the link between size and temperature was "generalisable and accurate". |
| He commented: "Head and colleagues' findings are the result of probably the first study in 'snake palaeothermometry', and as such must be viewed with caution." | He commented: "Head and colleagues' findings are the result of probably the first study in 'snake palaeothermometry', and as such must be viewed with caution." |
| Paul.Rincon-INTERNET@bbc.co.uk | Paul.Rincon-INTERNET@bbc.co.uk |