2016-12-08 / Columnists

Pets, Pets, Pets

Certain aspects of feline anatomy are marvels of design, and more useful than you’d think. Have you ever looked closely at a cat’s tongue and seen the tiny, sharp spikes? Have you ever watched or felt a cat flex and retract his claws? There are reasons for these unusual, physical features. Because of 3D printers, scientists are now viewing the adaptations from a mechanical engineering perspective.

A cat’s tongue: According to an 11/21/16 article in Science Daily (quoted here), Alex Noel, a doctoral candidate in mechanical engineering working at Georgia Tech, began exploring the odd “spines” on her own cat’s tongue, when she was helping to disentangle her cat after she licked a microfiber blanket and got her tongue stuck to it. Noel saw the Velcro-like hooks which glide over the fur until the hook catches a tangle or a snag.

Close-up photo of a cat’s tongue shows the tiny spikes Close-up photo of a cat’s tongue shows the tiny spikes “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,” said Noel.

During an annual meeting about Fluid Dynamics in Oregon, Noel described this concept, which she compares to using stiff versus soft hairbrushes, and what it might enable as a practical application for people.

“Most hairbrushes have spines that stick straight out. When hair collects on the brush it forms a thick mat that must be removed by hand,” Noel explained. “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. This configuration provides openings in a single direction, enabling the mat of hair around the bristles to be removed with a single finger swipe. These openings face the cat’s throat and are also why cats swallow their hair and end up with hairballs.”

Taking the concept to the lab and using macro- and high-speed video equipment, Noel and colleagues were able to zoom in and observe 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.

To help explore their theories, the researchers became the first group to 3D print a cat tongue mimic at 400% scale. They learned both the cat tongue and mimic are very good at cleaning and removing tangles in fur samples. They also discovered the cat tongue is self-cleaning since it’s easy to remove hair beneath the spines by simply brushing the tongue from tip to end.

This may have important implications in soft robotics, where researchers are still struggling to find ways for soft materials to grip surfaces. “The cat tongue is flexible, but it can pull apart tangles in fur,” Noel said. “So 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 within the medical field.”

Next, the group plans to study how the spacing of cat tongue spines affects friction. “With this knowledge, we can develop a hairbrush suitable for human grooming,” said Noel. “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.”

Noel and colleagues are planning to develop the cat tongue mimic technology through the Innovation Corps at Georgia Tech and talk to consumers, beauty specialists and medical device specialists around the U.S. about application opportunities. “We’ve already submitted a technology disclosure form and intend to file a patent within the next year,” she added.

A cat’s claws: There are three main reasons cats have claws- all for survival purposes. They need their claws for climbing up or down, hunting and defense. The claws need to be retractable because if they were out all the time, cats would get caught on many surfaces, as if their claws were Velcro. Cat claws grow from the last bone of a cat’s toes (distal phalanx), whereas our nails are attached to the skin of the fingers. Unlike us, a cat’s claws are completely attached to the bone because they get used and pulled so much and have to be strong. When a cat is not using his claws, they are retracted. The claw is pulled into the cat’s toe by a muscle and a tendon so it’s hardly visible. Some wild cats, like cheetahs, don’t retract their claws as much as domestic felines because they need the claws out to get a grip on the ground for sprinting.

A pet cat walks on his “fingertips.” Cats are “digitigrades” walkers, which means instead of walking on their heels and the balls of their feet, like humans do, they walk on tiptoe. Cats’ claws are made of the protein keratin which is the same protein that forms hair, fingernails and hooves. Claw tissue grows in layers, because of the quick, the living tissue at the core of the claw. The quick contains blood vessels and nerves, which will bleed if you’ve clipped your cat’s nails too short.

When you see pieces of your cat’s claws on the floor or embedded in his scratching post, it means the outside layer of his claw (sheath) has grown beyond the blood supply and falls off when he scratches—revealing a sharp new talon underneath. Cats generally shed each claw once every few months.

Speaking of Kitties- Babylon Animal Shelter (631-643-9270), Lamar St. W. Babylon has an assortment of cats and kittens—all spay/neutered, micro chipped, vaccinated, FeLV/FIV tested. Only thing missing is a HOME. “Roseanne” 6-505 is an adorable gray tuxedo while “Corey” 6-502 is a tiny male Sleeping Beauty Siamese mix.

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