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Thats what it wants to hear, because that sound is gonna mean thats where lunch is. A battle with Triceratops is more often than not a fight to the death. This herbivore has evolved into a tank. Now, as a Tyrannosaur specialist, I dont like to admit
探索与发现2013年
Tyrannosaurus Rex was of ten thousand pound, self-propelled, antitank weapon. Now, sixty five million years later, cutting-edge imaging technology lets us look deep inside their bodies to reveal just how the worlds greatest carnivores really work. Di
探索与发现2013年
The jaws of T-Rex are infamous and lethal, housing sixty teeth with some as long as 30 centimeters. Its skull is constructed of 64 bones designed to be light but strong. Its 16 times stronger than the jaws of an alligator. The front teeth are dagger-
探索与发现2013年
Triceratops protects itself with a bony shield called a frill. They can fend off an attacker with a pair of one-meter-long swords. Youve got to crush it. The only way to deal with this huge, curved, cantilevered, composite armor is a crushing blow wi
探索与发现2013年
Its unlike any other creature that has walked the planet. T-Rex is different. Something about Tyrannosaurs and Tyrannosaurus Rex itself is different than other predatory dinosaurs. But for such a celebrated killer able to take on the toughest creatur
探索与发现2013年
Hearing, smell and sight are all well refined. We can look at the sense of vision and see the attributes of a predator. T-Rexs eyes are 40 centimetres apart providing exceptional binocular vision, the ability to perceive depth. An eye is essentially
探索与发现2013年
Sauroposeidon towers over Deinonychus. In fact, its mammoth size is its primary defense. But this giant begins life very small. For Deinonychus, Sauroposeiden would be a great meal, at least the juveniles, because there wouldve been lots of them and
探索与发现2013年
And Sauroposeidon like most plant eaters are smelly. Unlike a meat eater, they produce huge amounts of waste, feces that form a trail marking everywhere theyve been. For Deinonychus, that odor is a dead giveaway. And this carnivores eyes can clearly
探索与发现2013年
These Olympic capabilities come down to one simple anatomical feature, its tail. Half the length of its body, it acts like a built-in counterbalance. By flicking it from side to side, it can make a sharp turn at full speed. If you were to look at Dei
探索与发现2013年
They are actually increasing their chance of getting a meal. Its a strategy still used today. Working together, lions will take on prey as big as a four-ton elephant, and they only have teeth and claws. Deinonychus employs an array of weaponry more p
探索与发现2013年
Deinonychus instinctively knows to go for this giants weak spot, its neck. Youve got the windpipe there. Youve got the jugular vein, which if opened up will mean that that Sauroposeidon is dead meat. But death does not come quickly or pleasantly. For
探索与发现2013年
Picture a living plane, and that gives you a sense of what Quetzalcoatlus would look like in life. And this is an animal that probably accelerates over 2.5Gs just on takeoff. Just beyond our comprehension. A Quetzalcoatlus is 10 times the weight of t
探索与发现2013年
propel this creature weighing as much as a grizzly bear, from a dead stop to a launch speed of 50 kilometers per hour all in a fraction of a second. I think that seeing a pterosaur like Quetzalcoatlus actually take off would have to be one of the mos
探索与发现2013年
Attacking another T-Rex may seem like suicide, but a creature with such a voracious appetite has to find food by any means. Cannibalism is the rule. Its not the exception. If youre a carnivore and theres meat there, you take advantage of it. In fact,
探索与发现2013年
--The irony for many predators is they are very concerned about injuring themselves. Even the toughest most well-armed man-eaters regularly come face to face with prey that can kill them. Whether you had the jaws of a Tyrannosaurus Rex, or are armed
探索与发现2013年
Nothing this large would achieve powered flight until the 20th century, 65 million years later. And Quetzalcoatlus still may hold the record for flight duration. Probably stay aloft for a week. Probably it could have gone for 25, 26,000 miles in a si
探索与发现2013年
I think that a big pterosaur on the ground wouldve been spooky because they would be moving around on all fours. Theyd probably have those sort of quick, precise movements like birds, but theyd be huge. Quetzalcoatlus lives by its own rules. Most mea
探索与发现2013年
Other carnivores are even more dependent on cognitive thought. For protection, Deinonychus relies primarily on its brain. --The brain structure of Deinonychus and its role are just really quite remarkable. Relatively speaking, Deinonychus has one of
探索与发现2013年
Mighty carnivores ruled a dangerous world in the Cretaceous Period. But being a super predator like Tyrannosaurus Rex is not easy. Just surviving to adulthood is a major feat, one that takes a decade or more of killing and eating some of the meanest
探索与发现2013年
By Lisa Schlein Geneva 01 February 2008 The U.N. refugee agency reports more than 40 staff and aid workers from private organizations have been withdrawn from the Eastern Chad town of Guereda following a series of armed attacks in the area. The aid w
VOA常速英语2008年（二月）