What matters for sea otters'prey perception

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Sea otters are pretty small compared to other marine mammals（哺乳動物）,which means that,despite their fur coats,they tend to lose heat quickly,and need lots of energy to keep up their body temperature.

“So they need to eat 25 percent of their body weight each day,”says Sarah McKay Strobel,a sensory ecologist at UC Santa Cruz.“But in order to eat that much food,it means sea otters need to find all that food.”She studied the otters'senses,to solve the mystery of how they're such efficient food catchers.Vision isn't reliable,she says—it's pretty dark and muddy underwater,and crabs and other smaller animals tend to hide.Hearing is also tough for otters in the noisy underwater environment.And sniffing's no good either.“When they're underwater,they're holding their breath.”

What's left is touch.So Strobel measured the sensitivity of the otters'paws and whiskers （須）.She blindfolded an otter named Selka,then presented it with plastic plates carved with tiny grooves(溝槽).Selka's job was to select the plate with two-millimeter grooves,which she'd been trained to associate with tasty food,instead of plates with differently sized grooves.

Turns out,Selka could tell even a quarter millimeter difference in the grooves with her paws—above and below water. “The fact that she was able to perform so well while moving extremely quickly I think is really interesting.It suggests that sea otters have very quick decisionmaking abilities and very quick sensory processing abilities,which makes sense when you think about the type of lifestyle they lead and how quickly they need to find food.”

For the record,humans can feel the difference,too,but it takes us 30 times longer,which might make sense.After all,we live in environments where touch is less important in a hunt than sight and sound.

Reading Check

1.Why do sea otters eat much food?

B.To swim faster.

C.To keep their fur thick.

D.To satisfy their good appetites.

2.What does paragraph 3 mainly talk about?

A.The use of plastic plates.

B.An experiment on Selka.

在與當(dāng)?shù)匚幕嘟Y(jié)合，卡拉米洛披肩成為墨西哥婦女身份的象征。“在我祖母生活的那個年代，全共和國的女人——無論貧窮還是富有，丑陋還是美麗，年長還是年幼——都會擁有一條自己的披肩。”（41）

C.An introduction to Selka.

D.The function of otters'touch.

3.What did Strobel find about sea otters'senses?

A.They have sharp vision.

B.They feature alert touch.

C.Their smell works very well.

D.Their hearing is very powerful.

4.What can be inferred about sea otters from the text?

A.They have enough food to eat.

B.Their whiskers work better than paws.

C.They are efficient decision-makers.

D.They respond very quickly in hunting.Language Study

Sentence for writing

Turns out,Selka could tell even a quarter millimeter difference in the grooves with her paws—above and below water.

【信息提取】Turns out為“It turns out that...”的變形，意為“結(jié)果……”。

【句式仿寫】結(jié)果證明，他解決這個問題的方法非常高效。

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