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Science has progressed to the point that we know how cats purr. In house cats, purrs are produced by vibrations of folds in the larynx. This was difficult to determine, as cats tend to stop purring when examined by a scientist, and cats that are restrained or unconscious do not purr. Such research is much more difficult for those studying lions and tigers.
But the details of who can purr and who can’t is not so simple. In a review of purring in cats, G. Peters tabulated that 20 of 36 species of cat have been said to purr, including lions, leopards, and other big cats. (As for the other 16, Peters wrote, there is not yet enough information to know whether they purr or not.) The question is whether the noises made by the big cats within the genus Panthera are true purrs — a sound created by moving air modulated by vocal folds as in smaller cats — or are actually different noises that only vaguely sound like purrs. The “rolling, gurgling growl” female big cats emit while in heat may be a kind of purr, or it may be something else entirely. And, Peters says, big cats might have the ability to purr but simply don’t. Somebody is going to have to make careful, close-up acoustic recordings of these purr-like sounds to better understand how they correspond to purrs of smaller cats, although I imagine finding volunteers for taping tigers in heat is a difficult task.
How much more frightening would it be to try looking down the throat of an actively purring big cat? Still, there is some research on the subject.
In 1989 anatomist M.H. Hast published a study on the larynges of big cats and found that lions, tigers, jaguars, and leopards had “a large pad of fibro-elastic tissue” near the forward portion of their paired vocal folds. (The exception was the snow leopard, a big cat that has never been heard to roar.) These expansions, in addition to the ability of these cats to lower the larynx thanks to the flexibility of the hyoid bone and its attachments, allowed lions, tigers, leopards, and jaguars to better transfer the energy required to make loud, low-frequency roars.
So it is possible that the biological differences that allows some big cats to roar has left them unable to purr. Read more about purr research at Laelaps. Link
(Image credit: Brian Switek)
About 10,000 Americans every year are diagnosed with laryngeal cancer, and most must submit to the surgical removal of their voice boxes. Machine replacements have, so far, sounded raspy and robot-like. But now medical researchers at the University of the Witwatersrand in South Africa have developed an device that fits into the mouth and tracks the normal movements of the tongue to produce simulated human speech:
The system uses a palatometer: a device that looks much like an orthodontic plate and is normally used for speech therapy. The device, made by CompleteSpeech of Orem, UT, tracks contact between the tongue and palate using 118 embedded touch sensors.[...]
To use the device, a person puts the palatometer in her mouth and mouths words normally. The system tries to translate those mouth movements into words before reproducing them on a small sound synthesizer, perhaps tucked into a shirt pocket.
Link via Popular Science | Image: Jaren Wilke/Megan Russell, The University of the Witwatersrand
Thread tiny cameras through the singers’ noses and focus on the larynx. Then have them sing sweetly and see what it looks like deep inside. The singers are Juleiaah Boehm, Emma Deans, Alexi Kaye, and Sally Stevens. -via b3ta
