A snake of a ton to read crossed climate
By Denis Delbecq • February 4th, 2009 in 22:34 · Category: Actuality
Know past to include the gift better and to imagine the future. An international team offers to study the ancient climates from size and from corpulence of the snakes. By studying giant's fossil (13 metres long for a ton) dating about 59 million years, she draws a new vision of the tropical climate of epoch (1). The region would then have known temperatures distinctly hotter than what was until now thought of.
At the beginning of epoch Paleogene (65 - 40 million years), the Earth was hotter than today. They bear a grudge for proof presence in the Arctic regions and in Siberia of fossils of crocodiles and of palms which point out that it did not freeze the winter. The consensus drawn of paléoclimatiques studies, pointed out the upper temperature of 30 ° its being today in high degrees of latitude, against a distance of 2 ° only under tropics. As though the planet had a thermostat capable of supporting a relating climatic stability in period of strong warming. If it are confirmed in future, jobs published on Thursday in Nature call into question this vision of a tropical climate protected from climatic warming.
The approach of eight researchers is at least original. The team was indeed based on the estimate of size and of weight of a huge snake, Titanoboa cerrejonensis, whose skeleton was found in the northeast of Colombia. A colossal snake, who measured perhaps thirteen metres long and weighed more than a ton! Four metres and several hundred kilogrammes more than the big anacondas contemporaries.
As the internal temperature of snakes varies with the external temperature, as for other poïkilothermes (the animals with cold blood), their metabolism is quick all the more as it is warm. And their maximum size also, since she depends closely on the metabolism. So that a snake of more than a ton could exist, it would be necessary therefore that the temperature which reigned then in the region is 30 ° in 34 °, estimate the researchers. She would therefore have attained 38 in 40°C during the maximum of temperature which occurred towards 55,8 million years before our epoch. Of what to produce terrible heatwaves …
Naturally, the researchers admit them - even the fragility of their conclusions. The reading of climates ancient passes by the analysis of "Proxys", of intermediaries, since there is not recording of temperature. In the field, the sources of errors are alas numerous. Besides, this study contradicts other jobs based on the analysis of the fossil flora in the same region. It will therefore be necessary to advance again so that the climatologists could finally know if tropics are protected of the sudden changes of climate by a natural thermostat, or if, as these jobs seem to show it, this hypothesis was erroneous. A question which remains essential for the modelling of climate to come on our planet.
(1) The United States, Canada, Panama.
Picture: A vertebra of Titanoboa facing a royal Python © Jason Head / Nature
Article read 1,973 times. Tags:climat, fossil, Paleocene, paleoclimatology, snake, Tropics
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