【英语时差8,16】锤头鲨的锤头

The Hammerhead’s Hammerhead These unique sharks have heads resembling flattened¹, T shaped hammers. But how would such a weird² head evolve? One hypothesis is that having their eyes spaced far apart might give these sharks better 3D vision. Another hypothesis is that sharks use the hammerhead literally³, smashing it against the ocean floor to stir up prey⁴. But both of these hypotheses have been ruled out experimentally. The hammer head may improve the sharks’ maneuverability and stability in the water, but more studies are needed to know if or how the hammer shape improves the sharks’ swimming abilities. What else could explain the hammer shape? It may have to do with electricity! All sharks have a special sensory⁵ system to detect weak electrical fields emitted by all marine⁶ animals. Sharks use this electro sense to find hidden or camouflaged⁷ prey. Researchers at the University of Hawaii found that hammerhead sharks have more electrosensory pores per surface area than other sharks do. In addition to higher pore density⁸, their wide head gives hammerheads a larger search. In tests, hammerheads were better able to find buried artificial electrical targets using the electroreceptors in their wide heads than non hammerhead sharks were. It’s sort of like scanning the beach with a metal detector⁹. If the diameter of your metal detector was bigger than that of your friend’s, you’d have the advantage since you could cover more area faster than she could. Like with a larger metal detector, the wide flat hammer shaped head might allow hammerheads to scan for prey more efficiently¹⁰ than their competitors.

1 flattened   

[医]（水）平扁的，弄平的

参考例句：

• She flattened her nose and lips against the window. 她把鼻子和嘴唇紧贴着窗户。
• I flattened myself against the wall to let them pass. 我身体紧靠着墙让他们通过。

2 weird   

adj.古怪的，离奇的；怪诞的，神秘而可怕的

参考例句：

• From his weird behaviour,he seems a bit of an oddity.从他不寻常的行为看来，他好像有点怪。
• His weird clothes really gas me.他的怪衣裳简直笑死人。

3 literally   

adv.照字面意义，逐字地；确实

参考例句：

• He translated the passage literally.他逐字逐句地翻译这段文字。
• Sometimes she would not sit down till she was literally faint.有时候，她不走到真正要昏厥了，决不肯坐下来。

4 prey   

n.被掠食者，牺牲者，掠食；v.捕食，掠夺，折磨

参考例句：

• Stronger animals prey on weaker ones.弱肉强食。
• The lion was hunting for its prey.狮子在寻找猎物。

5 sensory   

adj.知觉的，感觉的，知觉器官的

参考例句：

• Human powers of sensory discrimination are limited.人类感官分辨能力有限。
• The sensory system may undergo long-term adaptation in alien environments.感觉系统对陌生的环境可能经过长时期才能适应。

6 marine   

adj.海的；海生的；航海的；海事的；n.水兵

参考例句：

• Marine creatures are those which live in the sea. 海洋生物是生存在海里的生物。
• When the war broke out,he volunteered for the Marine Corps.战争爆发时，他自愿参加了海军陆战队。

7 camouflaged   

v.隐蔽( camouflage的过去式和过去分词 )；掩盖；伪装，掩饰

参考例句：

• We camouflaged in the bushes and no one saw us. 我们隐藏在灌木丛中没有被人发现。 来自《现代英汉综合大词典》
• They camouflaged in bushes. 他们隐蔽在灌木丛中。 来自《简明英汉词典》

8 density   

n.密集，密度，浓度

参考例句：

• The population density of that country is 685 per square mile.那个国家的人口密度为每平方英里685人。
• The region has a very high population density.该地区的人口密度很高。

9 detector   

n.发觉者，探测器

参考例句：

• The detector is housed in a streamlined cylindrical container.探测器安装在流线型圆柱形容器内。
• Please walk through the metal detector.请走过金属检测器。

10 efficiently   

adv.高效率地，有能力地

参考例句：

• The worker oils the machine to operate it more efficiently.工人给机器上油以使机器运转更有效。
• Local authorities have to learn to allocate resources efficiently.地方政府必须学会有效地分配资源。