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New Scientist, show that scientists have a sense of humour. The ideas are rather
amusing but they may just be true, too!
The first idea is based on the fact that modern reptiles are cold-blooded.
This means that the temperature of their bodies changes according to the
temperature of the surroundings. (Birds and mammals, on the other hand, are
warm-blooded so their body temperature stays reasonably constant even when
it's cold outside). Dinosaurs were giant reptiles, so they may have been cold-
blooded too. If they were, they wood have found it difficult to wake up on cold
mornings.
At about the time the dinosaurs died out, the climate was getting colder. So
the dinosaurs were probably slow and sleepy in the mornings before "they
warmed up. By contrast, the primitive mammals that lived then would have been
bright and active because their bodies were always warm. The mammals would
soon have discovered that the dopey dinosaurs were leaving a valuable source of
food unguarded - dinosaur eggs. So the dinosaurs who had dominated the earth
for so long may have died out because their eggs were eaten by the newly-
evolved mammals.
The second suggestion is based on another observation of present-day
reptiles. The sex of some turtles and crocodiles depends on the temperature of
the egg during incubation. The sex of the offspring of a dinosaur may have been
decided in the same way. It's easy to imagine the effect of a change of climate. If
the temperature dropped so it was cold all the year round, instead of just in
winter, all the dinosaurs born would have been the same sex. As the older
dinosaurs died, there would only be one sex of dinosaurs left. This would mean
no further breeding, and eventually no more dinosaurs.
There is no firm evidence for either of these explanations for the end of the
dinosaur, but they are both worth thinking about .
Notes:
dinosaur динозавр
extinct вымерший
Text 13
WHERE HAVE ALL THE DINOS GONE?
Of all the mysteries of the dinosaurs, none has generated more speculation
than why the beasts vanished some 65 million years ago. Increasingly, the
evidence points to an explanation that's literally out of this world. A giant
meteor or comet that crashed into the earth, blasting huge clouds of debris aloft.
With sunlight choked off for months, plant life would have dwindled, robbing
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