[ad_1]
Feline researchers have long believed that purring is produced by voluntary muscle contractions, but a new report indicates that this vibration in the larynx of cats can be explained by the myoelastic aerodynamic theory of phonation.
Studies on the complex action produced by a unique vibration in the larynx of cats, known as purring to most of us, have taken an important turn. It turns out that the biomechanics of the sounds that domestic cats make when they are comfortable or stressed may be closer to snoring than a voluntary muscle spasm.
New research published in Current biology suggests that masses of connective tissue are embedded in the vocal cords of the larynx of domestic cats. These may allow cats to produce self-sustained low-frequency oscillations without neural input or muscle contractions. Research has found that anatomical adaptations (the tissue “pads” of the vocal cords) respond to air entering the lungs.
What really is a purr?
Voluntary muscle contractions were thought to cause the vibrational component of purring. A contraction begins when the nervous system generates a signal that travels through a motor neuron to a neuromuscular junction. Once there, it releases a chemical message that tightens the fibers and triggers movement.
The authors of the new study suggest that purring comes from cats’ laryngeal pads. This is in line with the myoelastic aerodynamic theory, which states that vocal fold oscillation occurs as a result of asymmetric force functions on the closing and opening portions of the glottal cycle. The team maintains that the flow of air in and out of the lungs activates the vibrations of the vocal cords, producing sounds similar to the human voice and sounds characteristic of animals. To test this, the scientists experimented on eight larynxes that had been removed from domestic cats (all had been humanely euthanized when diagnosed with terminal illnesses). Their phonetic systems were housed in vertical tubes that supplied warm, moist air similar to the air that enters the body when breathing. The researchers were able to elicit the low-frequency phonation characteristic of purring without neural stimulation.
The study does not rule out the possibility that muscle contractions play a role in purring, but the team maintains that there is not enough evidence to conclude that it is the only cause of purring. Instead, research indicates that air dynamics can trigger the vibration mechanism.
Why do cats purr?
Cats purr throughout their lives, starting when they are kittens. Science has not yet fully understood why they purr in all circumstances, but biologists, veterinarians, and animal scientists have come to some general conclusions:
- Kittens purr so their mothers can find them
- Purring promotes wound healing.
- Purring produces serotonin, which is why it is often compared to human smiling.
- Domesticated cats not only purr when they are happy, but also when they are stressed
The article’s conclusions have caused some controversy. Biomechanical engineers interviewed by Science They claim that the experiment was limited to verifying the functioning of the larynx in isolation, without taking into account the complex systems of a live cat, which they consider a major oversight. Scientist David RiceFor example, he compared the research to removing the mouthpiece of a wind instrument and then analyzing the noise it produces regardless of the context of that instrument.
