Word: dinosaures
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What caused the death of dinosaurs? Scientists have blamed their demise on everything from lowered sea levels to lowered sperm counts. Now William Clemens, a paleontologist at the University of California, Berkeley, has added to the mystery. His expedition, sponsored by the U.S. Geological Survey, uncovered a cache of 180 dinosaur bones in Alaska, several hundred miles farther north than the creatures had previously been found. Among the fossils are skeletal remains of hadrosaurs, plant-eating duck-billed dinosaurs that stood up to 15 ft. high, and the teeth of a Tyrannosaurus-type carnivore...
...Clemens' view, the discovery indicates that at least some dinosaur species were not sensitive tropic dwellers but were able to survive through chilly and dark Arctic winters lasting from November to February. That theory tends to undermine the currently popular asteroid version of the apocalypse. According to that model, all dinosaurs perished when an asteroid or comet collided with the earth and tossed obscuring dust into the air, blocking sunlight and lowering ground temperatures. Clemens counters that dinosaurs living up north would hardly have noticed the difference, let alone be wiped out. Says he: "It doesn't matter if your...
...hoary belief involves dinosaur stupidity: the hapless creatures died out because their bodies continued to grow bigger while their brains remained small. Indeed, cranium measurements seem to indicate that at least some species were not terribly cerebral: one type of brontosaurus, for example, weighed about 30 tons, and probably had only a half-pound brain. If the dinosaurs did indeed become progressively less intelligent, the theory goes, they would have lost the ability to adapt to changes in the environment...
Even those dinosaurs known to have proportionately larger brains like tyrannosaurus may have simply been too massive to survive on land. How could their bulk have been lethal? According to one suggestion that many weekend athletes can identify with, the dinosaurs suffered from slipped disks, which left them unable to forage for food. Great heft could even trigger infertility. In 1946 a paleontologist concluded that because large animals do not shed excess heat as efficiently as small animals do, a temperature increase of just 2 degrees F could have baked the considerable testicles of a ten-ton male dinosaur enough...
...Alvarezes' staunchest critics has been William Clemens, a paleontologist at the University of California, Berkeley. After systematically sampling parts of the eastern Montana area, he declared that the layer of iridium and the bones of the last surviving dinosaur were too far apart to share any meaningful connection. Besides, he asked, why should the mammals have survived any Cretaceous catastrophe? Says he: "If you're going to have a nuclear winter killing off the dinosaurs, why didn't it kill off everything else...