生物学家发现了世界上最小的潜水哺乳动物 —— 水鼩的基因秘密。

Water shrews are diminutive, long-snouted mammals. They weigh less than one AA battery, and lose heat quickly, and burn energy constantly in tiny active muscles.

水鼩是一种体型纤小、长吻的哺乳动物。这类动物的体重还不足一节 AA（5号）电池，它们体内的热量会迅速流失，微小的活动肌肉中不断燃烧着能量。

But the ability to feed on all the insect larvae that live on the beds of rivers and streams has driven them to forage under water. The researchers from the University of Liverpool created a genetic family tree of related insect-eating mammals, including hedgehogs and moles.

然而，水鼩为了能吃到在河床和溪床上生活的所有昆虫幼虫，不得不到水下觅食。利物浦大学的研究人员们创建了一个有亲缘关系的食虫类哺乳动物的基因家谱，包括刺猬和鼹鼠。

They discovered shrews and moles had evolved the ability to store much more oxygen in their muscles. This allowed water shrews to hold their breath for up to 24 seconds – more than enough time to find all of that hidden aquatic prey.

研究人员们发现，鼩类和鼹鼠进化出了在肌肉中储存更多氧气的能力。这使水鼩能够在水中屏吸长达24秒，足以让它们寻觅那些隐蔽的水生猎物。

词汇表

diminutive 极小的，微小的
snouted 有…鼻子的
larvae 幼虫，单数为 “larva”
driven 驱使
forage 觅食
hedgehogs 刺猬
moles 鼹鼠
evolved 进化了
prey 猎物

阅读理解：请在读完上文后，回答下列问题。

1. How much do water shrews weigh?

2. True or false? Water shrews lose heat quickly and burn energy constantly.

3. Which animals mentioned are genetically related to water shrews?

4. How long can water shrews hold their breath for?

答案  

1. How much do water shrews weigh?
Water shrews weigh less than one AA battery.

2. True or false? Water shrews lose heat quickly and burn energy constantly.
True. Water shrews lose heat quickly and burn energy constantly in tiny active muscles.

3. Which animals mentioned are genetically related to water shrews?
Researchers from the University of Liverpool created a genetic family tree of related insect-eating mammals, including hedgehogs and moles.

4. How long can water shrews hold their breath for?
Water shrews can hold their breath for up to 24 seconds.