Published in Physics World, 1 Nov 2012
Cats are slow and elegant, dogs are quick and messy. But is the physics of their drinking all that different? Jon Cartwright reports
Cat and dog lovers, psychologists tell us, are a species apart. Those who like cats are sensitive yet open, while those who like dogs are bolder and more self-disciplined. But if there is one trait common to each, it is an endless fascination with their pets.
Roman Stocker is a case in point. “I love cats,” he says. “I just happened to be watching my cat over breakfast one morning, and then I started wondering: has anyone looked into how a cat laps?” To the average cat owner the question would have ended with idle musing, but to Stocker, an engineer at the Massachusetts Institute of Technology (MIT) in Cambridge, US, it was to spark a minor flurry of interest into our favourite animals’ drinking habits.
In fact, the science of water consumption in the animal kingdom is a little more complex than you might think. Some animals, such as frogs, absorb water through their skin, while some, such as the desert-dwelling kangaroo rat, can extract enough moisture from their food. Unsurprisingly, drinking as a means of water consumption is the most popular, but even it has its variants. Vertebrates with big cheeks – pigs, sheep, horses and so on – can suck in water, whereas mammals with no cheeks, including most carnivores, cannot. Instead, carnivores must use their tongues; they must lap. […]
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