If there is a cat in your house, you already know the most relaxing sound there is… our little friend’s purring! When it climbs on our knees and starts doing its characteristic “purr, purr”, everything calms down, and we might even fall asleep.
But, how do they make that noise? How are they able to maintain it as long as they want? Does it mean anything other than “I’m calm, happy and feel like being petted”?
There is no certainty about how do they do it. The most accepted theory is that it is produced by their diaphragm (the muscle that lies under the lungs and allows breathing) when it collapses the vein that runs through it. Because of it collapsing and relaxing, the vein would cause a more pressured blood flow that would produce that vibration, which would be then transmitted by the bronchi.
Another theory points to the fact that this sound is made by a set of “false vocal chords” that would graze against the real ones. This theory is the easiest to understand, but unfortunately it is also that which is most probably not true.
There is also a third theory that states that the sound is produced when the cats make their larynx vibrate at great speed. The sound would be produced when the air of their breathing goes through the larynx, just like when us humans make our throat vibrate. Bu there is an inconvenient to this theory: if this was the procedure they use, they could only purr for a few seconds.
For most of us it is a sound that they make when they feel happy, although specialists have found out that there are various types of purring. This way, they have made a distinction between the “thankful” purr, which they make when they like something, and the “anticipatory” purr, which they practice when they want to get something. For example, with the anticipatory they would be telling us that they want to be petted, and with the thankful one they are letting us know that they like the pampering.
It has equally been found out that the purring can happen when the animal is stressed out, hurt, or even close to death. For most experts, this fact has a surprising explanation: it is very possible that the cat is remembering happier days or a nice situation that eases its pain! Maybe this is due to -so they say- the fact that on their second day of life they are already able to make this sound in order to communicate with their mother. Are they remembering, then, the times in which they were protected and warm in a comfortable and safe place?
Here are some answers but, now that we remember it, there is one which usually pops up when we talk about this subject: is it true that cats are the only felines that purr? Well… there isn’t a clear answer for that either. It seems that pumas, cheetahs and ocelots can do it, even tigers in some circumstances.
Now you know a bit more on the way that your little hairy friend has to communicate with you. It seems incredible how many things they can tell us without talking and with a small sound!