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人们经常能看到海獭仰面浮在水上用石头敲开贝壳类动物进食的场景。科学家说，海獭可能很久以前就已经学会把石头当作工具使用了，而且似乎比其它的海洋哺乳动物都要早。一项遗传研究分析了在加利福尼亚海岸附近生活的100 多只海獭，结果表明，在几百万年前海獭的祖先就已经开始表现出这类行为了。请听 Helen Briggs 的报道。

Sea otters are often seen floating on their backs hammering at clams with rocks. They break open the shells to reveal a tasty meal inside.

New research suggests, even the ancestors of sea otters living millions of years ago knew how to do this. That's according to a genetic study of otters living off the Californian coast.

They are not the only marine mammals to use tools. Dolphins in Australia have been seen to use sponges to protect their noses when scouting for fish on the sea floor. But in dolphins, this seems to be a relatively new invention, happening less than 200 years ago. Evidence, say the scientists, that sea otters are very smart and have a natural ability to use tools.

词汇表

sea otters 海獭

on their backs 仰面躺着

hammering 用力锤打、敲击

genetic study 遗传研究

marine mammals 海洋哺乳动物

sponges （天然）海绵

scouting 寻找，搜索

invention 自发的新行为、新活动

natural ability 天生的能力，本能

测验

请听报道并回答下列问题。

1. What are sea otters often seen doing, according to the text?

2. What have dolphins in Australia been seen to use tools for?

3. True or false? In sea otters, using tools seems to be a relatively recent activity.

4. Which word in the text means ‘the information that shows if something is true or not'?

答案

1. What are sea otters often seen doing, according to the text?

Sea otters are often seen floating on their backs hammering at clams with rocks, according to the text.

2. What have dolphins in Australia been seen to use tools for?

They have been seen to use sponges to protect their noses when scouting for fish on the sea floor.

3. True or false? In sea otters, using tools seems to be a relatively recent activity.

False. New research suggests, even the ancestors of sea otters living millions of years ago knew how to use tools.

4. Which word in the text means ‘the information that shows if something is true or not'?

Evidence.