今天小编为大家整理的是
考点概览：
霸王龙即雷克斯暴龙(Tyrannosaurus Rex)，生存于白垩纪末期的马斯特里赫特阶(MAA)距今约6850万年到6500万年的白垩纪最末期，是白垩纪-第三纪灭绝事件前最后的非鸟类的恐龙种类之一。化石分布于北美洲的美国与加拿大，是最晚灭绝的恐龙之一。
霸王龙属暴龙科中体型最大的一种。体长约11.5-14.7米，头高最高近6米，平均体重约9吨。同时也是体型最为粗壮的食肉恐龙。和上次推送的蜥脚类恐龙相比，霸王龙的体态更为庞大，捕食习性也更为凶猛。所谓“霸王”二字，正是来源于霸王龙的体态和生存习性。
本次考试考察了霸王龙的捕食习性，即霸王龙是是食腐类动物还是常规的捕食者。关于霸王龙是捕食者还是食腐动物的辩论由来已久。学术界在1917年曾提出，由于霸王龙与萨龙出现了类似的骨骼结构，故而认定霸王龙也是食腐动物。但后来经研究发现，萨龙牙齿几乎没有任何磨损，而霸王龙化石中并未出现类似特征，所以这个观点不再被认真对待。事实上，自霸王龙第一次发现以来，大多数科学家都猜测这是一个捕食动物。就像现代大型食肉动物一样，霸王龙很容易地对另一个食肉动物进行杀戮。
关于霸王龙是否是食腐动物的研究，近年来并未被科学家们所放弃，以古生物学家杰克·霍纳为例，他着力于从霸王龙的肢体结构、嗅觉神经、视觉敏锐度、以及唾液成分猜测中判定霸王龙的食腐习性。目前，越来越多的科学家开始支持霍纳的观点，同时古生物学界倾向于认定霸王龙兼具捕食和食腐的双重特性。但由于霸王龙的化石现存数量亦是不多，所以文中并未能给出确切的结论，只是对两方的猜测予以呈现。
阅读文章：
A 2012 study by scientists Karl Bates and Peter Falkingham suggested that the bite force of Tyrannosaurus could have been the strongest of any terrestrial animal that has ever lived. The calculations suggested that adult T. rex could have generated from 35,000 to 57,000 Newtons of force in the back teeth. Even higher estimates were made by professor Mason B. Meers of the University of Tampa in 2003. In his study, Meers estimated a possible bite force of around 183,000 to 235,000 Newtons or 18.3 to 23.5 metric tons (20.2 to 25.9 short tons). Research done by Greg Erikson and Paul Gignac et al and published in the journal Scientific Reports indicates that Tyrannosaurus could bite down with around 8,000 pounds of force when feeding, exerting a pressure of 431,000 pounds per square inch with their teeth. This allowed Tyrannosaurus to drive open cracks present in bone during repetitive, mammal-like biting and produce high-pressure fracture arcades, leading to a catastrophic explosion of some bones and allowing the theropod to fully exploit carcasses of other dinosaurs, giving it access to the mineral salts and marrow within bone that other carnivores in the same environment could not access. Research done by Stephan Lautenschlager et al. of the University of Bristol, also reveals Tyrannosaurus was also capable of a maximum jaw gape of around 63.5 degrees, a necessary adaptation for a wide range of jaw angles in order to power the creature's strong bite.
The debate about whether Tyrannosaurus was a predator or a pure scavenger is as old as the debate about its locomotion. Lambe (1917) described a good skeleton of Tyrannosaurus close relative Gorgosaurus and concluded that it and therefore also Tyrannosaurus was a pure scavenger, because the Gorgosaurus teeth showed hardly any wear. This argument is no longer taken seriously, because theropods replaced their teeth quite rapidly. Ever since the first discovery of Tyrannosaurus most scientists have speculated that it was a predator; like modern large predators it would readily scavenge or steal another predator's kill if it had the opportunity.
Paleontologist Jack Horner has been a major advocate of the idea that Tyrannosaurus was exclusively a scavenger and did not engage in active hunting at all, though Horner himself has claimed that he never published this idea in the peer-reviewed scientific literature and used it mainly as a tool to teach a popular audience, particularly children, the dangers of making assumptions in science (such as assuming T. rex was a hunter) without using evidence. Nevertheless, Horner presented several arguments in the popular literature to support the pure scavenger hypothesis:
Tyrannosaur arms are short when compared to other known predators. Horner argues that the arms were too short to make the necessary gripping force to hold on to prey.
Tyrannosaurs had large olfactory bulbs and olfactory nerves (relative to their brain size). These suggest a highly developed sense of smell which could sniff out carcasses over great distances, as modern vultures do. Research on the olfactory bulbs of dinosaurs has shown that Tyrannosaurus had the most highly developed sense of smell of 21 sampled dinosaurs. Opponents of the pure scavenger hypothesis have used the example of vultures in the opposite way, arguing that the scavenger hypothesis is implausible because the only modern pure scavengers are large gliding birds, which use their keen senses and energy-efficient gliding to cover vast areas economically. Researchers from Glasgow concluded that an ecosystem as productive as the current Serengeti would provide sufficient carrion for a large theropod scavenger, although the theropod might have had to be cold-blooded in order to get more calories from carrion than it spent on foraging (see Metabolism of dinosaurs). They also suggested that modern ecosystems like the Serengeti have no large terrestrial scavengers because gliding birds now do the job much more efficiently, while large theropods did not face competition for the scavenger ecological niche from gliding birds.
Tyrannosaur teeth could crush bone, and therefore could extract as much food (bone marrow) as possible from carcass remnants, usually the least nutritious parts. Karen Chin and colleagues have found bone fragments in coprolites (fossilized feces) that they attribute to tyrannosaurs, but point out that a tyrannosaur's teeth were not well adapted to systematically chewing bone like hyenas do to extract marrow.
Since at least some of Tyrannosaurus's potential prey could move quickly, evidence that it walked instead of ran could indicate that it was a scavenger. On the other hand, recent analyses suggest that Tyrannosaurus, while slower than large modern terrestrial predators, may well have been fast enough to prey on large hadrosaurs and ceratopsians.
Other evidence suggests hunting behavior in Tyrannosaurus. The eye sockets of tyrannosaurs are positioned so that the eyes would point forward, giving them binocular vision slightly better than that of modern hawks. Horner also pointed out that the tyrannosaur lineage had a history of steadily improving binocular vision. It is not obvious why natural selection would have favored this long-term trend if tyrannosaurs had been pure scavengers, which would not have needed the advanced depth perception that stereoscopic vision provides. In modern animals, binocular vision is found mainly in predators.
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