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Blue whales off the California coast make calls that, sped up 10 times, sound like (sound of two-part call). The original is a wall-rattling frequency too low for us to hear. Scientists analyzed around 2,500 of those calls, and found that the second part (sound) is nearly ___1___ in pitch every time from each whale: 16 hertz, or four octaves below middle C. And the slight ___2___ in frequency that do exist are only a tenth of the difference between a C and a C sharp. Those findings appear online in the Journal of the Acoustical Society of America.
The researchers don't know how many different individual whales they caught singing, or why even they sing at all. But past studies suggest only blue whale males make calls like this. So the investigators speculate that males might ___3___ to a single common pitch as a sort of ___4___.
Thanks to the Doppler effect, females swimming towards a male would hear a slightly higher pitch; swimming away, a lower-pitched moan. Serenade ___5___—you might be swimming solo tonight.
identical variations synchronize mating beacon out of tune
加利福尼亞海岸的藍(lán)鯨會(huì)發(fā)出嘀嘀嘀嗚嗚嗚這樣兩部分的叫聲。當(dāng)然這是在將其叫聲頻率提高10倍之后聽(tīng)到的，未處理過(guò)的頻率過(guò)低，人耳是無(wú)法聽(tīng)到的。科學(xué)家分析了約2500種那樣的叫聲之后發(fā)現(xiàn)，那種每一頭鯨魚(yú)發(fā)出的嗚嗚嗚的叫聲，音高幾乎一模一樣：16赫茲，比中央C音低4個(gè)八度。即使有差異，也是極其微小的，只有C調(diào)與升C調(diào)之間音高差異的十分之一?！睹绹?guó)聲學(xué)學(xué)報(bào)》電子版刊登了上述發(fā)現(xiàn)。 研究人員對(duì)它們研究的鯨魚(yú)中有多少頭發(fā)聲、為什么發(fā)聲都一無(wú)所知。不過(guò)，以往的研究表明只有雄性藍(lán)鯨才會(huì)發(fā)出這樣的聲音。因此，研究人員猜想雄鯨們可能協(xié)同一致，發(fā)出同種音高的聲音作為求偶信號(hào)。 由于多普勒效應(yīng)，雌鯨們要是向某雄鯨投懷送抱，它們就會(huì)聽(tīng)到較高昂的呼喚；不過(guò)，雌鯨們要是對(duì)某雄鯨置之不理，那聽(tīng)到的就是低沉的呼喚了。小夜曲唱走調(diào)，那雄鯨老兄你今夜就得獨(dú)自徘徊了╮(╯▽╰)╭