Posts Tagged ‘lap’

Physics of lapping lets cats drink without mess

// November 24th, 2010 // 2 Comments » // How Things Work, Recent Research, Science at Home

First up, apologies on the lateness of my post. A whole week has gone past! Oh me! I humbly do beseech you to forgive this old salt and do throw myself upon the deck in penance. Me only defense is that I have just moved from Canberra to Adelaide, and me Schooner does need an awful lot of bubble wrap. To distract you from me own slackness, I have scoured the nets for the cutest science story evah. I ply you with kittens thusly:

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Cats are a more delicate and refined animal than messy, smelly and drooly dogs. I’ve always been a cat person. I think they have higher standards. Turns out they also drink better than dogs.

Both dogs and cats lack the complete cheeks that humans have, which means they can’t drink water by suction like we can. Dogs get around this by using their tongues as a ladle, cupping the water from bowl to throat.

Cat’s do it differently. They lap water briskly, but not like a ladle. Instead, they DEFY GRAVITY and make the water lift up into the air like a glorious floating blob of refreshment.

Sounds crazy, but it’s true. When they dip into the dish, water adheres to the dorsal (top) side of their tongue. The surface tension (sweet, sweet hydrogen bondage) of the water drags a column of water into the air. The cat can thus pull water into its mouth using inertia.

The competition between inertia moving water up and gravity pulling it down sets the lapping frequency of the cat. Smaller cats with smaller tongues lap faster to drink, large cats lap slower. Observation of lapping frequency in big cats like lions shows the same kind of trend, suggesting they use the same physics as the household feline.

Cats might do this because it’s a neater, cleaner way to drink and it keeps their whiskers nice and dry. Whiskers have an important sensory function, so it’s worth the effort to keep them tidy.

The research was published in Science, and began when a researcher was watching his own cat drink. A video of the researcher and cat is below, and shows in super slow mo exactly how water defies gravity when a cat enters the equation.

Did you hear that? Did you? Not only is it physics, hydrogen bonding and gravity defying, plus, PLUS, the tongue could have implications for robotics of the future. Yeah. Robot cat tongues. It’s going to happen.

Actually tongues are very interesting. They obviously have no bones for support, so instead they have a muscular hydrostat system where support comes from muscles. The same thing happens in octopus tentacles, where muscles stretch in one of three directions: Along the tentacle (longitudinal), across the tentacle (transverse) or wrapping around the tentacle (helical.) When an octopus moves, one muscle contracts to become shorter which forces the muscles around to stretch, supporting the movement like a skeleton.

Cats and octopus. You know this post was worth the wait.

ResearchBlogging.orgReis, P., Jung, S., Aristoff, J., & Stocker, R. (2010). How Cats Lap: Water Uptake by Felis catus Science DOI: 10.1126/science.1195421






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