評論
打印
Now listen to part of a lecture on the topic you just read about.
現在來聽一段有關你剛剛讀到的話題的演講。
The hypothesis that the Edmontosaur migrated every winter is not convincing.
埃德蒙頓龍每年冬天遷徙的假設沒有說服力。
First, the Edmontosaur did not have to migrate to find food.
首先，埃德蒙頓龍不需要遷徙去尋找食物。
One hundred million years ago, the summer temperatures in the North Slope area were warmer than they are today.
在一億多年年前，北坡地區的夏日氣溫比現在要暖和。
And remember, in arctic regions like the North Slope, the Sun shines 24 hours a day at the peak of the summer.
而且，別忘了，在像北坡一樣的北極地區，夏天高峰太陽24小時都照耀著。
The warm temperatures and extensive daylight created incredibly good growing conditions for plants,
暖和的氣溫和充足的日照為植物提供了好到難以置信的生長條件，
so much vegetation was produced during the summer that when the vegetation died as the winter came,
夏天里生出了太多的植物，當植物因為冬天來臨而死去的時候，
there was a lot of nutritious dead vegetation around in the winter.
冬天里有很多營養的死去的植物。
The Edmontosaur could have easily lived on the dead plant matter during the winter.
埃德蒙頓龍可以輕松地依靠這些死去的植物度過冬天。
Second, just because Edmontosaurs lived in herds doesn't mean they migrated.
第二，埃德蒙頓龍成群的生活，不表示它們會遷徙。
Animals live in herds for many other reasons.
動物們因為很多別的原因而群居。
Living in herds, for example, provides animals with extra protection from predators.
比如，成群的生活，給動物們提供了額外的保護，以抵其獵食者。
Having extra protection is useful even for the animals that live in the same area the whole year round.
額外的保護對那些常年居住在同一個地方的動物們來說也是很有用的。
A modern example of this is the Roosevelt elk—a large plant-eater.
一個現代的例子就是羅斯福馬鹿，一種大型的草食動物。
Roosevelt elks live in the forests of the western United States.
羅斯福馬鹿住在美國西部的森林里，
They live in herds but they do not migrate.
它們群居，但是它們不遷徙。
Third, although adult Edmontosaurs were capable of migrating long distances, what about Edmontosaurs that were not yet adults?
第三，即使成年埃德蒙頓龍能夠長度遷徙，那些未成年的埃德蒙頓龍們怎么辦呢？
Juvenile Edmontosaurs were not physically capable of travelling the great distances required to reach warmer territories
新生的埃德蒙頓龍生理上不具備去更溫暖的領域所需要長途跋涉的能力，
and would have slowed the herd so much that the herd never would have made it to its destination.
會大大拖慢獸群的速度，導致獸群永遠到不了目的地。
The herd could not have left the juveniles behind because the juveniles would not have survived on their own.
而獸群也不會留下這些新生兒不管，因為新生兒不能獨立生活。
So the whole herd had to stay where they were and survive on the cold North Slope.
所以整個獸群只好留在它們所在的地方，靠北坡生存下去。
