[ti:Scientists Model an Ancient Shark Able to Eat Whales in a Few Bites] [by:www.51voa.com] [00:00.00]更多听力请访问51VOA.COM [00:00.04]Scientists used the ancient remains of bones and teeth [00:06.12]to recreate a big shark that lived in the oceans millions of years ago. [00:12.04]The creature was so huge a recent study estimated [00:16.92]it could have eaten something the size of a killer whale in just five bites. [00:22.84]For the recently published study, researchers used fossil evidence [00:29.44]to create a three-dimensional (3D) model of the megalodon [00:35.08]— one of the biggest fish of all time. [00:39.20]The study was published in Science Advances. [00:43.04]It said megalodon was around 16 meters [00:46.88]from nose to tail — bigger than a school bus. [00:50.60]It is also several times the size of today's great white shark. [00:56.72]Megalodon's large mouth meant it could feed on big creatures. [01:01.72]Once it filled its stomach, it could travel the oceans [01:05.88]for months at a time, the researchers suggested. [01:09.76]The megalodon was a strong swimmer, too. [01:13.76]Its average swimming speed was faster than sharks today [01:18.16]and it could have traveled across several oceans [01:21.48]with ease, scientists said. [01:24.44]John Hutchinson, a co-writer of the study, [01:28.68]described the megalodon as a "superpredator." [01:32.84]He added, "There is nothing really matching it." [01:37.04]It has been difficult for scientists to get a clear picture [01:41.36]of the megalodon, said study co-writer Catalina Pimiento. [01:46.48]The skeleton is made of soft cartilage [01:49.88]that does not become a fossil very often, Pimiento said. [01:54.36]So the scientists used the few fossils that are available, [01:59.84]including a rare collection of back bones [02:03.40]that has been at a museum in Belgium since the 1860s. [02:08.52]Researchers also brought in many megalodon teeth, [02:12.88]each as big as a closed human hand, Hutchinson said. [02:18.08]Special images of modern great white sharks [02:21.76]helped researchers recreate the rest of the creature. [02:25.96]Researchers estimate that the megalodon [02:29.28]would have weighed around 70 tons, or as much as 10 elephants. [02:35.00]Even other high-level hunters may have been food for the megalodon, [02:40.68]which had a mouth almost 2 meters wide, Pimiento said. [02:45.84]Megalodons lived an estimated 23 million to 2.6 million years ago. [02:53.16]Since megalodon fossils are rare, [02:56.08]these kinds of models require a "leap of imagination," [03:00.20]said Michael Gottfried who studies ancient bones [03:03.72]at the Michigan State University. [03:06.32]Gottfried was not involved in the study. [03:09.84]But he said the study's findings are reasonable [03:13.64]based on what is known about the large shark. [03:18.08]I'm John Russell. 更多听力请访问51VOA.COM