【英语时差8,16】鼩的吱吱声

Why Shrews Twitter Small mouse like mammals, shrews are not actually rodents¹ or even closely related. Shrews are noisy little creatures– constantly twittering and squeaking² as they scramble³ through their habitat. But why? All that noise could surely attract the attention of predators⁴, so there must be an important reason for their endless twittering. One possibility is that shrews use calls for communicating with neighbors or mates. But some researchers have hypothesized that the twittering serves a totally different function– echolocation. Since shrews have poor eyesight, listening to the way their calls echo back from the surroundings might help them navigate⁵ through their environment. A team of German biologists reasoned that if calls were used solely⁶ for communication, then calling behavior should change depending on the presence or absence of other shrews. But if calls were used for echolocation, calling should change in response to changes in the physical surroundings rather than social situations. The researchers discovered that the twittering of shrews did not change in response to the simulated presence or absence of other shrews. But when the researchers changed the thickness of the straw bedding in the shrews’ enclosures, the rate of twittering changed too. This suggests that shrews may use their calls as a simple type of echolocation, and not only for communication. The echoes from their calls help them navigate in the dark and avoid obstacles in their path. Although more research is needed to understand how shrews use their twitter calls in the wild, the discovery is exciting news since shrews are one of the first land animals that might use echolocation.

1 rodents   

n.啮齿目动物( rodent的名词复数 )

参考例句：

• Rodents carry diseases and are generally regarded as pests. 啮齿目动物传播疾病，常被当作害虫对待。 来自《简明英汉词典》
• Some wild rodents in Africa also harbor the virus. 在非洲，有些野生啮齿动物也是储毒者。 来自辞典例句

2 squeaking   

v.短促地尖叫( squeak的现在分词 )；吱吱叫；告密；充当告密者

参考例句：

• Squeaking floorboards should be screwed down. 踏上去咯咯作响的地板应用螺钉钉住。 来自《简明英汉词典》
• Can you hear the mice squeaking? 你听到老鼠吱吱叫吗？ 来自《简明英汉词典》

3 scramble   

v.爬行，攀爬，杂乱蔓延，碎片，片段，废料

参考例句：

• He broke his leg in his scramble down the wall.他爬墙摔断了腿。
• It was a long scramble to the top of the hill.到山顶须要爬登一段长路。

4 predators   

n.食肉动物( predator的名词复数 )；奴役他人者（尤指在财务或性关系方面）

参考例句：

• birds and their earthbound predators 鸟和地面上捕食它们的动物
• The eyes of predators are highly sensitive to the slightest movement. 捕食性动物的眼睛能感觉到最细小的动静。 来自《简明英汉词典》

5 navigate   

v.航行，飞行；导航，领航

参考例句：

• He was the first man to navigate the Atlantic by air.他是第一个飞越大西洋的人。
• Such boats can navigate on the Nile.这种船可以在尼罗河上航行。

6 solely   

adv.仅仅，唯一地

参考例句：

• Success should not be measured solely by educational achievement.成功与否不应只用学业成绩来衡量。
• The town depends almost solely on the tourist trade.这座城市几乎完全靠旅游业维持。