英语听力:自然百科 世上最大的蛇化石(在线收听

 Scientists have uncovered the world's largest snake.

 
A study published in Thursday’s edition of the science journal Nature reveals the discovery in Colombia. Measuring about 45-feet long and weighing more than a ton, the so-called Titanoboa would have been longer than a bus. The remains have led experts to believe the Titanoboa was a boa(蟒蛇)-like snake that lived about 60 million years ago during the Paleocene epoch(古新纪), a 60-million-year period following the extinction of the dinosaurs.
 
The partial remains were found in an open-air coal mine in the northern Colombian state of La Guajira. Following the discovery, the fossils, specifically the vertebrae(椎骨), were sent to the Smithsonian Tropical Research Institute in Panama and later to the Florida Natural Science Museum in Gainesville for study. Scientists also believe the discovery sheds light on climate conditions in the area at the time when the snake lived.
 
"The size in which they can grow is limited by the mean annual temperature, by the temperature in which they live. So if you increase the temperature that they live in throughout the year, then you can increase the size of the snake. "
 
Based on the snake’s size, the team was able to calculate that the mean annual temperature at equatorial south America 60 million years ago would have been about 91 degrees Fahrenheit, about 10 degrees warmer than today. Aside from its size, the Titanoboa discovery may also offer significant clues as to how the earth could look as it continues to warm.
 
  原文地址:http://www.tingroom.com/lesson/zrbaike/2009/255543.html