The science of cats' lapping
Roman Stocker, of MIT, was inspired by his cat, Cutta Cutta, to study how cats drink. Although humans are able to suck liquids, dogs and cats are unable to seal their cheeks and so need to lap. While dogs bend their tongue to form a scoop cats, both domesticate and wild, were found to use a different mechanism.
It was thought that cats would use the tiny hairs on their tongue to help pull the water in but they found that this was not the case. When cats lap only the tip of their tongue comes into contact with the water. The water sticks to the tip of the cat's tongue and is pulled up when the tongue retracts to form a water column. The cat then closes its mouth around the column in order to drink the liquid.
A suggestion why cats might have adopted such a method of drinking is their dislike of water. It was proposed that, as the cat's face is very sensitive, it wants to keep it as dry as possible. If cats lapped liquids in the same manner as a dog there would be a lot more splashing and they wouldn't be able to keep their faces dry.