大象的嗅觉动物界最灵敏
<p> 大象的嗅觉动物界最灵敏 <span word="Researchers">Researchers</span> <span word="have">have</span> <span word="discovered">discovered</span> <span word="that">that</span> <span word="African">African</span> <span word="Elephants">Elephants</span> <span word="have">have</span> <span word="the">the</span> <span word="largest">largest</span> <span word="number">number</span> <span word="of">of</span> <span word="genes">genes</span> <span word="dedicated">dedicated</span> <span word="to">to</span> <span word="smell">smell</span> <span word="of">of</span> <span word="any">any</span> <span word="mammal">mammal</span>. 研究人员发现，非洲大象拥有数量最多的基因，这些基因有利于所有哺乳动物的嗅觉。 <span word="Given">Given</span> <span word="the">the</span> <span word="size">size</span> <span word="of">of</span> <span word="their">their</span> <span word="trunks">trunks</span>, <span word="and">and</span> <span word="how">how</span> <span word="important">important</span> <span word="it">it</span> <span word="is">is</span> <span word="to">to</span> <span word="their">their</span> <span word="survival">survival</span>, <span word="it">it</span> <span word="is">is</span> <span word="probably">probably</span> <span word="unsurprising">unsurprising</span> <span word="that">that</span> <span word="an">an</span> <span word="elephant">elephant</span> <span word="s">s</span> <span word="nose">nose</span> <span word="is">is</span> <span word="not">not</span> <span word="only">only</span> <span word="the">the</span> <span word="longest">longest</span> <span word="in">in</span> <span word="the">the</span> <span word="animal">animal</span> <span word="kingdom">kingdom</span>, <span word="but">but</span> <span word="also">also</span> <span word="the">the</span> <span word="most">most</span> <span word="effective">effective</span>. <span word="In">In</span> <span word="comparison">comparison</span>, <span word="humans">humans</span> <span word="and">and</span> <span word="other">other</span> <span word="primates">primates</span> <span word="have">have</span> <span word="a">a</span> <span word="poor">poor</span> <span word="sense">sense</span> <span word="of">of</span> <span word="smell">smell</span>. <span word="The">The</span> <span word="functions">functions</span> <span word="of">of</span> <span word="these">these</span> <span word="genes">genes</span> <span word="are">are</span> <span word="not">not</span> <span word="well">well</span> <span word="known">known</span>, <span word="but">but</span> <span word="they">they</span> <span word="are">are</span> <span word="likely">likely</span> <span word="important">important</span> <span word="for">for</span> <span word="the">the</span> <span word="living">living</span> <span word="environment">environment</span> <span word="of">of</span> <span word="African">African</span> <span word="elephants">elephants</span>, <span word="said">said</span> <span word="author">author</span> <span word="Dr">Dr</span> <span word="Yoshihito">Yoshihito</span> <span word="Niimura">Niimura</span> <span word="of">of</span> <span word="the">the</span> <span word="University">University</span> <span word="of">of</span> <span word="Tokyo">Tokyo</span>. <span word="Apparently">Apparently</span>, <span word="an">an</span> <span word="elephant">elephant</span> <span word="s">s</span> <span word="nose">nose</span> <span word="is">is</span> <span word="not">not</span> <span word="only">only</span> <span word="long">long</span> <span word="but">but</span> <span word="also">also</span> <span word="superior">superior</span>. <span word="The">The</span> <span word="sense">sense</span> <span word="of">of</span> <span word="smell">smell</span> <span word="is">is</span> <span word="critical">critical</span> <span word="to">to</span> <span word="all">all</span> <span word="mammals">mammals</span>, <span word="and">and</span> <span word="they">they</span> <span word="use">use</span> <span word="it">it</span> <span word="for">for</span> <span word="sniffing">sniffing</span> <span word="out">out</span> <span word="food">food</span>, <span word="avoiding">avoiding</span> <span word="predators">predators</span>, <span word="finding">finding</span> <span word="mates">mates</span> <span word="and">and</span> <span word="locating">locating</span> <span word="their">their</span> <span word="offspring">offspring</span>. <span word="In">In</span> <span word="a">a</span> <span word="study">study</span> <span word="published">published</span> <span word="in">in</span> <span word="Genome">Genome</span> <span word="Research">Research</span>, <span word="scientists">scientists</span> <span word="examined">examined</span> <span word="the">the</span> 13 <span word="mammal">mammal</span> <span word="species">species</span> <span word="and">and</span> <span word="found">found</span> <span word="that">that</span> <span word="African">African</span> <span word="Elephants">Elephants</span> <span word="have">have</span> <span word="twice">twice</span> <span word="the">the</span> <span word="number">number</span> <span word="of">of</span> <span word="smell">smell</span> <span word="genes">genes</span> <span word="as">as</span> <span word="dogs">dogs</span> <span word="and">and</span> <span word="five">five</span> <span word="times">times</span> <span word="more">more</span> <span word="than">than</span> <span word="humans">humans</span>. <span word="They">They</span> <span word="have">have</span> <span word="around">around</span> 2,000 <span word="genes">genes</span> <span word="alone">alone</span> <span word="that">that</span> <span word="are">are</span> <span word="dedicated">dedicated</span> <span word="to">to</span> <span word="scent">scent</span>. <span word="Humans">Humans</span> <span word="in">in</span> <span word="comparison">comparison</span> <span word="have">have</span> <span word="just">just</span> <span word="under">under</span> 400 <span word="and">and</span> <span word="other">other</span> <span word="primates">primates</span> <span word="like">like</span> <span word="chimpanzees">chimpanzees</span>, <span word="even">even</span> <span word="less">less</span>. <span word="The">The</span> <span word="study">study</span> <span word="found">found</span> <span word="that">that</span> 20,000 <span word="genes">genes</span> <span word="are">are</span> <span word="responsible">responsible</span> <span word="for">for</span> <span word="the">the</span> <span word="sense">sense</span> <span word="of">of</span> <span word="smell">smell</span> <span word="in">in</span> <span word="mammals">mammals</span>, <span word="of">of</span> <span word="which">which</span> <span word="around">around</span> <span word="half">half</span> <span word="are">are</span> <span word="functional">functional</span>, <span word="but">but</span> <span word="the">the</span> <span word="collections">collections</span> <span word="differ">differ</span> <span word="for">for</span> <span word="each">each</span> <span word="species">species</span>. <span word="Horses">Horses</span> <span word="have">have</span> <span word="around">around</span> 1,000 <span word="smell">smell</span> <span word="genes">genes</span>, <span word="rabbits">rabbits</span> <span word="around">around</span> 750 <span word="and">and</span> <span word="rats">rats</span> <span word="about">about</span> 1,200. <span word="The">The</span> <span word="large">large</span> <span word="repertoire">repertoire</span> <span word="of">of</span> <span word="elephant">elephant</span> <span word="genes">genes</span> <span word="might">might</span> <span word="be">be</span> <span word="attributed">attributed</span> <span word="to">to</span> <span word="elephants">elephants</span> <span word="heavy">heavy</span> <span word="reliance">reliance</span> <span word="on">on</span> <span word="scent">scent</span> <span word="in">in</span> <span word="various">various</span> <span word="contexts">contexts</span>, <span word="including">including</span> <span word="foraging">foraging</span>, <span word="social">social</span> <span word="communication">communication</span>, <span word="and">and</span> <span word="reproduction">reproduction</span>, <span word="added">added</span> <span word="Dr">Dr</span> <span word="Niimura">Niimura</span></p>
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