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Shredding machine

发布时间:2019-03-07 06:19:01来源:未知点击:

By Jeff Hecht A huge predatory dinosaur attacked its prey not by biting it, but by slashing its flesh like a medieval mace. Allosaurus slammed its upper jaw into its victims, ripping off flesh with its sharp teeth, says Emily Rayfield of the University of Cambridge. Modern komodo dragons use the same high-impact, slash-and-tear technique. Palaeontologists believe the jaws of the massive Tyrannosaurus rex were so powerful they could crush bones. Even though Allosaurus lived in the late Jurassic, some 85 million years earlier than T. rex, it left more fossils. But it has not been studied in as much detail. When Rayfield looked at its jaw muscles, she found “the bite of Allosaurus is by no means pathetic, but by no means as big as modern predators like lions.” It was only about a quarter as strong as T. rex’s bite or that of a modern crocodile. To try to understand the reason for the comparatively weak bite, Rayfield created a computer model of the skull of “Big Al”, an allosaur fossil from Wyoming. This enabled her to calculate the force that its jaws would need to break the skull of a living animal. The allosaur skull is lighter and has more openings than that of T. rex, but the structural engineering analysis showed that it was many times stronger than necessary to withstand biting forces. The combination of the weak bite and the strong light skull led her to conclude that Allosaurus had a different feeding strategy, perhaps opening its jaws wide and slamming the upper jaw into its prey. “It’s not what I would have expected, but it seems to fit the evidence in general,” says Tom Holtz, a dinosaur palaeontologist at the University of Maryland in College Park. He points out that the massive jaws of tyrannosaurs were atypical – most other predators were more lightly built. More at: Nature (vol 409,