The Mystery of Purrs

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The cat’s purr has long puzzled scientists, New Scientist reported.

Now, a new study is shedding some light on how cats are able to produce those sounds.

A research team explained that the type of sound an animal makes is linked to their vocal folds. These folds are made up of two bands of smooth muscle tissue in the larynx, a hollow tube in the middle of the neck through which air passes to generate sounds.

Larger animals usually have larger vocal folds and can generate low-frequency sounds.

However, domestic cats are quite small and have relatively short vocal folds. Yet, they are able to produce high-frequency sounds – meowing and screeching – and low-pitched purrs.

To figure out how, researchers cut the larynxes of eight domestic cats that had been euthanized because of illness.

The findings showed that the larynxes of domestic cats produce purring sounds when air passes through them without the need for muscle contraction. Instead, it was the connective tissue structures within the vocal folds that lowered the frequency of the sounds they produced.

The team noted that while these connective tissue structures had been previously identified in cats, this is the first study to link them directly to purring.

Still, scientists might know the how but they still aren’t sure about the why.

They think, however, that purring is believed to signal contentment, encourage interaction, and serve as a soothing mechanism that aids in healing after injuries.