aReferring to 7 June 2012 – Catalyst
1. 當貓放鬆, 躺在你大腿上時. – 此時咕嚕咕嚕聲帶愉悅,舒適的.
2. 當貓肚餓,緊急需求食物,想盡辦法要主人起身給他餵食時. – 此時咕嚕咕嚕聲沒有愉悅,並且有點像犀牛的聲音.
而貓這兩種咕嚕咕嚕聲, 經實驗, 主人都會辨別出那種聲音是貓在放鬆, 那種是貓在餓餓.
A cat has two difference kind of purrs for two difference purposes:
1. relaxing purr: when the cat is lying on your lap – sounds more pleasant.
2. hungry purring: when the cat urgently wants of food , to find a way to tell the master to get up and feed them – sound not so pleasant and more like a rhino
After recording the sound of the cat purrs, according to the analysis of the results , I did draw a chart as follows:
The figure below are two kinds of cat purring audio analysis diagrams .- dBs ( Noise, in decibels, the volume of the purr ) , Frequency ( frequency) .
上圖是兩種貓咕嚕咕嚕聲頻分析圖. - dBs ( 聲浪分貝, 即聲量的大小), Frequency ( 頻率).
1. 貓放鬆時(上圖的黑線), 在錄音聲軌上顯示從大聲到細聲, 愈細聲頻率就愈高(即愈頻密).
2. 貓肚餓時(上圖的紅線), 在錄音聲軌上顯示在大聲時會突然出現一高峰(英文叫 Voice Peak), 這高峯大約可以由三百與六百赫茲之間。而這高赫茲就跟嬰兒的哭泣或遇險呼叫聲的頻率相同. 這就是為什麼會使主人那麼心急如焚般去搶救心愛的愛貓了.
另外, 從貓發出的咕嚕咕嚕聲頻中, 它的超低音頻, 只有大象才會發出這低音頻. 那為什麼一隻這麼細小的動物可以做到?
原來, 貓是可以聲帶獨立抽動. 跟人類不一樣的.
亦即是人類發聲是由空氣經過聲帶(請看下圖, 聲帶vocal folds是氣管中的兩片白色由軟骨組成的帶狀組織.), 和聲帶周圍的肌肉的抽動來震動(vibrate)聲帶, 然而人類這個動作, 是只能同時震動兩邊的聲帶.
而貓, 他竟然可以控制只是一邊抽動, 或是兩邊同時的抽動. 並且當空氣被傳遞過去的聲帶時，貓還可以在不斷purring咕嚕咕嚕. 來減低了purring 的harmonic 和諧.而使得主人感到這種迫切關注的求救的反應.
1. the black color line: is the purring sound of a relaxed cat, a sound track from loud to low, the lower the noise the higher the frequency .
2. the red color line: is the purring sound of a hungry cat, displayed on the recording sound track appeares a peak (called the Voice Peak ) , this peak is about three hundred and six hundred Hz. This high Hertz is the sound of a baby crying, a distress call frequency of the sound , which is why the master is so anxious to rescue the beloved cat.
In addition, the frequency of the purring sound from the cat , it ‘s ultra-low, apparently only an elephant can make such a low audio sound. Why such a small animal like a cat can do that?
It turnes out that the cat can control the vocal chords independently. Not like humans, they have no independent vocal cord control .
The picture below shows human vocal cords, the vocal folds inside the trachea are shown as two white cartages. The twitching of the muscles around the vocal cords does control the vibration of the chords, but humans can only vibrate both chords simultaneously, whereas cats can contol them independently and thus are able to create such different sounds.
film authentic cat purrs
1. to film their cats purring in two situations. One when they’re relaxed, sitting on a lap,
2. the other when they want something – food,
or to get their owner out of bed.
the original researcher, Dr Karen McComb from the UK
Time to bring our DIY film unit back from the field and reveal what this is all about.
That’s a relaxed pussy cat.This is the relaxed purr. Alright, it sort of descends down as we get higher in the frequency.
That one’s a hungry pussy cat. This second purr has been termed a ‘solicitation purr’. And the UK scientist found it was consistently rated more urgent and far less pleasant. The question is, why is it so?See this right here, this peak? That’s sitting around four hundred and seventy, four hundred and eighty hertz. That is the hidden signal inside the solicitation purr.
normal voice sounds are made by air passing the vocal folds. But a cat is simply too tiny to make a sound this deep. To get this low, it should be the size of an elephant.
But we now know how cats do it and it’s really ingenious. Instead of passing air through the vocal folds, the cat can just twitch its vocal folds independently.
But here’s where it gets really clever. What the UK researchers discovered is an additional component – and extra voicing, like a cry or a meow, where the air is passed up past the vocal folds whole the cat is still purring.
They call it the voiced peak. Sitting between three-hundred and six-hundred hertz, this voiced peak is the same frequency as a baby’s cry. Effectively, inside the solicitation purr is the buried distress call of a human baby.
So it’s that hidden voiced peak in the solicitation purr that makes that purr less harmonic. And that’s what drives the owner mad and into action
read more :
Cats ‘exploit’ humans by purring
Cat owners may have suspected as much, but it seems our feline friends have found a way to manipulate us humans.
Researchers at the University of Sussex have discovered that cats use a "soliciting purr" to overpower their owners and garner attention and food.
Unlike regular purring, this sound incorporates a "cry", with a similar frequency to a human baby’s.
The team said cats have "tapped into" a human bias – producing a sound that humans find very difficult to ignore.
Dr Karen McComb, the lead author of the study that was published in the journal Current Biology, said the research was inspired by her own cat, Pepo.
read more : http://news.bbc.co.uk/2/hi/8147566.stm