The whiskers are the first step sense of touch in a highly sensitive way for rats. When the whiskers brush over the walls, ground, obstacles, food, and other rats, they will send messages to the rat's brain. In this way, the rats can tell the direction and how far each whisker moves. As the rat moves through the landscape he feels all the objects and textures near his face, and constructs an image of the world around him. This image may be far more detailed than what the rat can see through his eyes.
Recent researches have shown that the rat's whiskers may also be used in hearing as well. Rats can feel the vibrations when sound travels around them.
Reasons above can be explanations why rats are so tricky and hard to be captured.