Evidence of feline intelligence can easily be found beyond the laboratory, as anyone who has lived with a cat will agree. Curiosity, for example, a well-known indicator of intelligence,  is exhibited by many domestic cats. They enjoy frequent investigations of their surroundings, even if these do not change at all.
   Cats have been known to learn how to open doors and windows, and sometimes even the refrigerator. They can recognize familiar sounds, especially favorite ones, such as a can of their food being opened or your food being unwrapped. Some cats can learn to operate machinge for their own amusement, knowing which button to push to turn on the radio, for example, or how

to play and eject a tape from a video recorder. 
   In general, cats are also able to recognize and adapt to the behavioral limits set by their owners. They can be trained to use a litterbox, particularly if taught at an early age; the majority will also learn not to jump onto kitchen surfaces and the like,  unless the owner does not mind. Cleaver cats who are not supposed to do so will only jump on worktops when their owners are not around.
   Without the help of an alarm clock, many cats seem to know instinctively when it is time for their owners to wake up, the time for their regularly scheduled meal, or when it is time for their owners to return home, when they can be seen waiting by the door. Cats are