All it took was watching her cat lick a thick, microfiber blanket and become stuck, tongue out. Alexis Noel — a doctoral candidate in mechanical engineering working in the Hu Biolocomotion Lab at Georgia Tech — was inspired to explore the odd “spines” she noticed while helping to disentangle her cat’s tongue.
That tongue is covered in tiny Velcro-like hooks and, as it glides over fur, the hooks catch tangles and snags.
But that’s not all.
“When the cat’s tongue hits a snag, it pulls on the hooks, which rotate to penetrate the snag even further. Like a heat-seeking missile for snags, the hook’s mobility allows the cat to better tease tangles apart,” Noel said.
Using macro and high-speed videography equipment, Noel and colleagues zoomed in and observed the unique shape and flexibility of the tongue spines during grooming.
“In terms of shape and sharpness, it reminds me of cat claws. And this opens yet another question of why all claws are shaped so similarly,” Noel said.
Noel compares the cat-tongue mechanism to using stiff hairbrushes — but the cat comes out on top.
“A typical hairbrush has spines that stick straight out,” Noel said. “When hair collects on the brush it forms a thick mat that must be removed by hand.
“In comparison, the cat’s flexible spines make it easier to clean. When not in use, the spines on a cat tongue lie nearly flat against its surface, like overlapping shingles. These spines all face in a single direction — the cat’s throat. This explains why cats swallow their hair and end up with hairballs.”
To help explore their theories, the researchers became the first group to 3-D print a cat-tongue “mimic” at a scale of 400 percent.
“Both the cat tongue and the mimic are very good at cleaning and removing tangles in fur samples,” Noel said. “We also discovered that the cat tongue is self-cleaning as it’s easy to remove hair beneath the spines by simply brushing the tongue from tip to end.”
This discovery may have important implications for soft robotics, as researchers are still struggling to find ways for soft materials to grip surfaces.
“We’re trying to develop a cat tongue-inspired surface based on our 3D-printed mimic. The flexibility of cats’ tongue spines may have broad-reaching applications from an easy-to-clean hairbrush to wound cleaning,” Noel said.
“With this knowledge, we can develop a hairbrush suitable for human grooming,” Noel said. “We’d also like to study the tongues of tigers, lions and other large cats to understand how tongue spines scale across the cat family.”
In the meantime, Noel and colleagues are planning to develop and patent the cat-tongue mimic technology. They also plan to talk with consumers, beauty specialists and medical device specialists about application opportunities.