陳蕙雅思教材 - 雅思閱讀精選 (Marine Mammals)

Marine Mammals

Since there is such anabundance of food in the sea, it is understandable  

that some of theefficient, highly   adaptable,warm-blooded mammals that

evolved on land shouldhave returned to the sea.  Those that didhave      

flourished.  Within about  50 million years -- no timeat all,

geologically  speaking --  one  of  the  four kinds  of       mammals  that

has  returned to  a  marine environment has developed into thelargest of

all animal forms, thewhale. A      second kind, the seal,  has produced what is

probably the greatest population  of largecarnivorous  mammals on Earth.

This suggests that these"top dogs" of the ocean are prospering and

multiplying.  However, such has not  been the case, atleast  not  for the  

last  150 years. Trouble has closed in on thesemammals in the form of

equally warm-blooded andeven more efficient and adaptable predators,

humans. At sea, as onland,          humans have now positionedthemselves on the

top of the whole greatpyramid of life, and they have caused serious          

problems for the mammalsof the sea. There is a simple reason for this.

Marine mammals have themisfortune to be       swimming aggregatesof commodities

that  humans want: fur, oil and meat. Even so,  they might not be so

vulnerable  to human depredation  if they did not, like  humans, reproduce

so slowly. Every yearhumans take more than 50 million        tonsof fish from

the oceans withoutcritically depleting the population of any species. But

the slow-breeding    mammals of the sea have been all but wipedout by humans

seeking to satisfy theirwants and whims.

海洋哺乳動物 既然海洋中有如此豐富的食物，一些原本在陸地生存的高效率的，適應性強的暖血型動

物返回海洋生存是不難理解的。 那些已經返回海洋的哺乳動物種族繁榮。 在大約 5 千萬年 間(這在地質學上不過是彈指一揮間)，返回海洋的 4

種浦乳動物之一的鯨已成為體積最龐大 的動物。 而另一種哺乳動物海豹，它的數量恐怕是地球上大型食肉哺乳動物中最大的。 這

似乎表明這些海洋中的"大哥大"們人丁興旺，一派繁榮景象。但至少在近 150 年以來，事實 並非如此。  

同樣是暖血動物而且效率更高、適應性更強的捕食者，人類，成為這些哺乳動 物的日益迫近的威脅。  

在陸地和海洋，人類都已處在巨大的生物金字塔的最頂端，成為所 有生物的主宰，並給海洋哺乳動物帶來巨大的危脅。 原因很簡單。 這些哺乳動物不幸成為

人類所需要的一堆遊動著的商品，如皮毛、油和肉。  儘管如此，如果它們不象人類一樣繁 殖如此緩慢，它們對人類的掠奪也不會如此無能為力。

每年人類從海洋中捕撈約 5 千萬噸 的魚類，但這並未導致任何魚種的滅絕。但繁殖緩慢的海洋哺乳動物卻因為有了一心只想滿 足一已私欲的人類而瀕臨。