Cats were as soon as believed to produce purrs through cyclic contractions of singing fold muscles, however a current study suggests no such contractions are required. Anatomical studies found a distinct pad in cat singing folds allowing them to produce low frequencies, prompting questions about our current understanding of feline purring.
A felines larynx can create purring noises without cyclical neural input.
Felines are vocal animals: they meow, screech, and purr. From a voice production point of view, the meows and the screeches are not special. Their sound is created in the felines throat or “voice box” just like vocalization in human beings and lots of other mammals.
In contrast, cat purrs were long thought to be extraordinary. Research going back half a century suggests that the purrs are produced by an unique mechanism– through cyclical contraction and relaxation of the muscles in the vocal folds within the larynx, needing consistent neural input and control from the brain..
Revealing the purring mechanism.
A current study, led by Austrian voice scientist Christian T. Herbst at the University of Vienna, now shows that these cyclic contraction are not required to generate feline purrs.
Information from a regulated lab experiment shows that the domestic feline throat can produce impressively low-pitched sounds at purring frequencies without any cyclical neural input or repetitive muscle contractions being required. The observed noise production mechanism is strikingly comparable to human “creaky voice” or “vocal fry”..
” Anatomical examinations exposed a special pad within the felines singing folds that may discuss how such a little animal, weighing only a few kilograms, can regularly produce sounds at those incredibly low frequencies (20-30 Hz, or cycles per second)– far listed below even than lowest bass sounds produced by human voices,” states Herbst.
The research studys findings– while not constituting an outright falsification of the previous theory– are a clear indicator that the existing understanding of cat purring is incomplete, and warrants even more research..
Reference: “Domestic cat larynges can produce purring frequencies without neural input” by Christian T. Herbst, Tamara Prigge, Maxime Garcia, Vit Hampala, Riccardo Hofer, Gerald E. Weissengruber, Jan G. Svec and W. Tecumseh Fitch, 3 October 2023, Current Biology.DOI: 10.1016/ j.cub.2023.09.014.