Cats often spend up to a quarter of their waking hours licking their fur, and I believe many owners have been licked by them. In fact, felines have tiny and sharp papillae structures on their tongues, which we often call "barbs."

Barbs remove fleas and lower body temperature. Georgia Tech researchers Alexis Noel and David Hu recorded high-resolution images and videos of tongue tissue movements after death in six species of cats, from domestic cats to lions. CT scans of cat tongues show that they are not covered by solid cones, but by claw-shaped hooks. They lie flat and rear-facing, and they find the tips of their barbs particularly well-shaped to draw saliva deep into all their fur to aid in cleaning.

Their barbs are actually U-shaped grooves, and saliva is stored in the grooves through capillary action. When the hair is washed, the barbs stand up. As the tongue depresses the hair, the upright barbs just make contact with the skin beneath the hair. Saliva on the skin surface effectively removes dirt and cools the body.

In addition, the researchers were inspired by barbs and made a 3D printed tongue brush. The brush is a reduced version of cat barbs. As you can see, the brush can not only be used for combing, but can also be used to apply lotion to the cat's skin. on without shaving. This proves that TIGR is better than ordinary brushes. For this reason, researchers have applied for a patent for it.

Figure 1: Characteristics and functions of barbs

(A) Domestic cats clean their hair

(B) A close-up of its tongue, showing all the barbs pointing to the left, toward the throat

(C) Four stages of barb movement

(D and E) During cleansing, the hair is separated by the barb movement on the tongue, exposing the skin. The heat from the tongue and skin is shown in white in Figure D, and after the barb movement, evaporation causes the temperature to drop, as shown in dark purple in Figure E.

Figure 2: Cat’s tongue and its capillary papillae.

(A) Feline tongue, domestic cat, lynx, snow leopard, tiger, lion

(B) CT scan of barbs from domestic cats to lions

(C) CT scan of the tongue of a domestic cat, in which the scan of B is taken from the red circle area

(D)The relationship between barb height and body weight

(E) Capillary action of domestic cat barbs, sucking red food dye within 0.1 seconds

(F) Time course of red food dye inhalation

Figure 3: The geometry of barbs used by cats to clean their hairstudy.

(A) Schematic diagram of a cat cleaning its hair. The tongue compresses the hair and then moves to the right

(B) Close-up view of hair before and after compression. When the tongue is pushed downward, the hair depth hfur and porosity ϵ both decrease

(C) Compressed hair height hfur and barb height hpapillae. The dotted line hpapillae=hfur represents the dividing line between licking and non-licking cats.

Figure 4: Saliva transfer from tongue to fur

(A) Cat hair will form hair balls when wet

(B) Schematic diagram of agglomerated hair, with reduced local porosity

(C) The blue food dye transferred from the tongue to the hair, the length corresponding to the combing length

(D) A single barb is licked like this with blue dye

(E) There is a direct relationship between the amount of saliva transferred and the barb speed. The vertical gray bar indicates the grooming speed of the cat, and the dotted line indicates the porosity of the wet hair

Picture 5: TIGR brush

(A) Use UV dye to irradiate domestic cat tongue

(B) 3D printed simulation showing flexibility similar to a cat’s tongue

(C and D) 3D printing and humans using hair brushes, each color represents a sequence of consecutive trials in the rainbow, and the peak force represents the hairball encountered

(E) The schematic diagram shows that when the cat tongue barbs meet the messy hair, they encounter the tangle (left), grab the tangle (middle), and rotate until it is vertical (right)

In addition to its powerful function of cleaning hair, what other secrets does the cat tongue hide?

· Create a water column to drink water

· Distinguish the type and freshness of water

· Effectively remove bones from meat

· Marking method, leave your own scent

All in all, to borrow a sentence from David Hu: "Cat tongue is like a very smart tool." Although the imitation cat tongue brush is not yet planned to be produced, I believe that with the emergence of TIGR, it will definitely be used in the near future. It will be used on a large scale to show its great value.