Cats will chase escaping or fast moving prey. Chasing involves pursuing prey rapidly. Therefore, the cat will usually be running at full speed. All senses are centred on the prey to prevent its escape: thus ears are directed forward, eyes are wide and focused on the prey and the whiskers are usually flexed outwards away from the face and slightly forward. During a chase, the cat may change direction quickly depending on the direction in which the prey move
The following video illustrates chase behaviour towards a mock prey item (toy mouse).