Saturday, November 13, 2010

Do you know cat's tongue has hooks, spikes that defy GRAVITY, help them to drink ?

NUGGET : Cat tongue point downwards while drinking!

What's those spikes for ?

A cat's tongue has a special area in the center. In the center of your cat's tongue are papillae -- little hooked, hair-like growths that face towards the back of the mouth. These strong hooks are made from keratin (the same stuff found in human fingernails).
  • Self-grooming. The hooks help clean and separate the cat's fur. This doesn't mean your cat won't appreciate some help with grooming sometimes! Brushing your cat can help remove dead skin and loose hair -- and help prevent hairballs.
  • Holding food. The hooks can help gather food into the mouth.
  • Hunting. The hooks can help hold struggling prey in place.Taste. Special mushroom-shaped papillae at the tip and along the sides of the tongue hold large taste buds. Another set of cup-shaped papillae sit at the back of the tongue.
  • To drink water. The spikes and hooks are used to retain some water molecules as the tongue retreat back into the mouth, taking inertia with it. Close it's mouth before gravity take over to cause water molecules to drop back down.
Cutta Cutta drinking
Video: Pedro M. Reis, Sunghwan Jung, Jeffrey M. Aristoff and Roman Stocker
Do you ever wonder how cats drink ?

No one has quite appreciated how impressively they drink. Using high-speed videos, Pedro Reis and Roman Stocker from the Massachusetts Institute of Technology has shown that lapping cats are masters of physics. Every flick of their tongues finely balances a pair of forces, at high speed, to draw a column of water into their thirsty jaws.

Drinking is more of a challenge for cats than for us. They have to drink from flat, horizontal bodies of water. Even with our hands tied, we could do that just by putting out mouth at the surface and sucking, but then we have large cheeks that can form a proper seal. Pigs, sheep and horses have the same ability, but cats and dogs do not. Their cheeks don’t extend far enough forward so they have to use a different technique: lapping.

When the cat’s tongue touches the liquid surface, some of the liquid sticks to it through liquid adhesion, much as water adheres to a human palm when it touches the surface of a pool. But the cat draws its tongue back up so rapidly that for a fraction of a second, inertia — the tendency of the moving liquid to continue following the tongue — overcomes gravity, which is pulling the liquid back down toward the bowl. The cat instinctively knows just when this delicate balance will change, and it closes its mouth in the instant before gravity overtakes inertia. If the cat hesitated, the column would break, the liquid would fall back into the bowl, and the tongue would come up empty.

While the domestic cat averages about four laps per second, the big cats, such as tigers, know to slow down. Because their tongues are larger, they lap more slowly to achieve the same balance of gravity and inertia.

With these videos slowed way down, the researchers established the speed of the tongues’ movements and the frequency of lapping. Knowing the size and speed of the tongue, the researchers then developed a mathematical model of lapping, which involves the ratio between gravity and inertia. For cats of all sizes, that number is almost exactly one, indicating a perfect balance.

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