The awesome science of the cat’s tongue inspires a novel hair brush

Hair brush based in cat's tongue
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Hair brush based in cat’s tongue. From video below.

You might know that the cat’s tongue is covered with around 290 tiny but prominent backward facing spines (papillae) made of keratin. Our nails are made of keratin. And cats groom themselves for about 2.4 hours daily.

Cat tongue's showing the spines

Cat tongue’s showing the spines. Photo: Alexis Noel.

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Recent research, using CT scans, discovered that the part of the cat’s papillae are hollow. They researched several species of cat: tiger, lion, domestic cat, bobcat, puma and snow leopard.

Cavity in Spines

The hollowed out spines carry saliva in to the deep recesses of the cat’s fur or efficient cleaning. The process also cools the cat.

The spines are about 2mm in length. There is a U-shaped cavity at the tip which fills with a tiny but significant amount of the cat’s saliva, 4 microliters to be precise. This saliva is deposited deep into the fur right down to the skin. The spines or spikes of the tongue are attached to the tongue with a hinge -like mechanism. These allow the spikes to drive through fur in a “a low-drag configuration” until they hit a tangle.

“The papillae…feature a hollow cavity at the tip that spontaneously wicks1 saliva from the mouth and…releases it onto hairs”.


The grooming action cools the cat because it removes heat from the cat in the saliva which is deposited in the fur where it evaporates. Except for their paws domestic cats don’t have sweat gland so this form of heat loss is important. Note: cats also cool themselves via panting which is cooling by the evaporation of saliva on the tongue.


The researchers believe that their study could inspire businesses to create a more efficient cleaning process using robotics and ‘biologically inspired technologies for cleaning and depositing fluids into…arrays of flexible filaments’.

They created an experimental brush using the findings which is shown in the video. It was made with a 3-D printer.

Some extra info added later

We are told that the tongue-inspired grooming brush requires as little as half of the force of a traditional brush to be applied when pulled through here.

Prof Hu (the lead researcher of the Georgia Institute of Technology in Atlanta) said that L’Oreal had contacted him to discuss his findings. It appears that the research could lead to an improved hairbrush to potentially be marketed by L’Oreal.

The tongue acts like a loofah and a sponge at the same time. The patient application has been filed for their brush. They claim that hairbrush technology has been moribund i.e. dormant and not progressive for a long time.

The earliest known comb is believed to date from 8000 BC. It was carved from animal born in Syria. The basic shape of the comb is not changed since.

The researchers also believe that a cat’s tongue could help in the application of fluids or in the cleaning of carpets or in the application in medicine.

1. To ‘wick’ means to absorb or drain like a wick. A wick is a bundle of fibres which, through a capillary action, draws up fluids.

2. Study: Cats use hollow papillae to wick saliva into fur – by Alexis C. Noel and David L. Hu, published on the website.

Useful tag. Click to see the articles: Cat behavior

Note: sources for news articles are carefully selected but the news is often not independently verified.

Michael Broad

Hi, I'm a 74-year-old retired solicitor (attorney in the US). Before qualifying I worked in many jobs including professional photography. I love nature, cats and all animals. I am concerned about their welfare. If you want to read more click here.

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2 Responses

  1. Jane says:

    This is a wonderful development, a very informatve article.

    I once shared life with a curious, characterful little cat named Gerry. He had endured a protracted period of severe neglect before he came to me. His mouth was 100% ravaged by Calici.

    His tongue had been so deeply ulcerated that once healed, it had no lingual papillae at all. With his tongue as smooth as a dog’s, he couldn’t keep his coat clean, detangle it or spread the sebaceous oils down the length of his long hairs. He had to have his teeth extracted too.

    We did our best, daily grooming, clipping, the occasional bath, dry microfibre cloths helped too, but he was always a scruffy, loveable mess. Gerry always groomed himself, but all this did was spread saliva through his coat.

    Oh how I wished that someone would invent THIS very brush! I approached the engineering department of our local uni’ & vet school, but no one could work out how to scan a cat tongue properly, yet alone work out how to ‘print’ this intricate, complex surface. The technology was just not quite there yet.

    I hope that this brush goes beyond the proof of concept stage. If such a cat brush was in production, it would be so helpful to cats who need serious help with grooming that is kind & effective.

    Thank you for sharing this important news!

    • Michael Broad says:

      Hi Jane. I would definitely get a brush like this if it was available. It was informative for me to learn that the papillae hold some saliva which is deposited deep inside the coat. I think we are world experts on cats by now. 🙂

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