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  3. One of Nature’s most exciting mysteries is how pigeons find their way home o

One of Nature’s most exciting mysteries is how pigeons find their way home o

游客2023-10-10  43
问题     One of Nature’s most exciting mysteries is how pigeons find their way home over vast distances. Now German scientists believe they have discovered how the birds do it. Research has revealed that tiny iron structures in their beaky(鸟嘴)allow them to analyze the earth’s magnetic field—much like a compass(罗盘). Through the signals picked up, the birds can work out where they are and set out on the best course home.
    As well as pigeons, many other birds display a remarkable ability to fly thousands of miles to return to a specific garden or tree year after year. Scientists are suggesting they may have similar iron-containing cells in their beaks.
    In the past, experts have suggested the birds use the sun and stars to navigate, although in 2004 researchers found that many follow roads rather than their internal compass to plan their route. However, scientists have long believed that they can in some way use the natural magnetism of the earth to navigate. The recent study by German scientists has revealed how this may be possible.
    The research used X-rays to examine the upper beaks of pigeons. They found that within the skin lining are tiny iron-containirg particles(微粒)in nerve branches which are arranged in a 3D pattern. The team, led by Gerta Fleissner, concluded that this allows the birds to react to the external magnetic field of the planet and work out their precise location.
    She pointed out that similar iron-containing cells had been found in the beaks of robins, warblers and chickens so it may well turn out to be the way that other species also navigate.
    Scientists are still discovering more about the incredible abilities of the pigeon.
Questions: [br] In 2004 some researchers found that many birds do not______to plan their route.
选项
答案 use their internal compass
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